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As a type of secondary metabolites produced by plants during long-term ecological adaptation, cutin and wax are widely involved in many resistance physiological processes including stress defense and resistance to pests and diseases, playing critical roles in the plant-pathogen interaction, thus becoming an important part of plant disease resistance mechanism. With the development of molecular biology, there is an increasing understanding on the cutin and wax metabolism and their mechanisms against fungal disease in plant. With prior researches mainly focused on the constitutive resistance and inducible resistance of plant cutin and wax, the present study, with a review of the research progress achieved on the plant cutin and wax biosynthesis and its disease resistance mechanism, is aimed to put forward prospects for future research. It was concluded that 1) as the main components of the cuticle, the first line of defense for plants against pathogen infection, cutin and wax play a critical role in physical resistance (physical barrier) and chemical resistance (bacteriostasis) as constitutive resistance components, 2) They can also play the role of inducible resistance components and 3) in addition to being the main component of the cuticle to exert physical resistance, the inducible cutin and wax component can also act as a signal molecule or inducer to activate downstream resistance reactions and exert its chemical resistance function. In the future, the research concerning cutin and wax can be focused on an in-depth explanation of the mechanism of cutin and wax inducible resistance, so as to further enrich the theoretical system of plant chemical ecology. In addition, cutin and wax biopesticides (plant immunity inducers) can be developed based on the inducible resistance of cutin and wax to provide new insight for the plant diseases control. [Ch, 1 fig. 71 ref.]
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Objective  To further the relationship of Ceracris kiangsu with their host plants, an investigation was conducted of its feeding preferences and developmental status when living on three different host plants.  Method  The grid area calculation method was employed to determine the feeding selectivity of bamboo locust of different ages and observation was made of the effects of three different host plants on the body weight, body length, pre-laying period, spawning volume and survival rate of C. kiangsu.  Result  The feeding preference of host plants of C. kiangsu changes as its age accumulates; the average feeding area of first-instar nymphs was Zea mays (474.67 mm2±66.03 mm2)＞Phyllostachys edulis (179.33 mm2±41.38 mm2)＞Miscanthus sinensis (76.00 mm2±42.11 mm2) while the feeding area of the nymphs from the second to the fifth instar on M. sinensis was significantly larger than that on the other two host plants(P＜0.05). The weight growth of different host plants was Z. mays (0.301 g±0.015 g)＞M. sinensis (0.295 g±0.022 g)＞Ph. edulis(0.229 g±0.027 g) whereas the length growth of different host plants was M. sinensis (25.120 mm±0.682 mm)＞Z. mays (24.860 mm±1.436 mm)＞Ph. edulis (22.910 mm±2.914 mm). When breeding on different host plants, C. kiangsu demonstrates significant differences in the pre-spawing period of the adults(P＜0.05) and the average pre-spawning period of the three populations was M. sinensis (55.4 d± 6.9 d)＞Ph. edulis (41.7 d±2.2 d)＞Z. mays (41.2 d±3.7 d), and the pre-spawning period of the population feeding on M. sinensis was significantly longer than that of those feeding on the other two plants(P＜0.05). The population of spawn per female was significantly different after feeding on different host plants, and the result was Ph. edulis (122.00 seeds±6.08 seeds)＞Z. mays (121.00 seeds±12.70 seeds)＞M. sinensis (21.00 seeds±2.89 seeds), yet there was no significant difference in the survival rate of C. kiangsu feeding on different host plants(P＞0.05) with the survival rates as follows: Ph. edulis(88.33%±1.70%)＞M. sinensis (86.67%±1.66%)＞Z. mays (83.33%±1.60%).  Conclusion  With the difficulty of obtaining the host plants and the weight growth, body length calculation and reproductive capacity of C. kiangsu taken into consideration, corn leaves, compared with other two host plants which are not easy to obtain in large quantities, can be planted in large quantities, thus making the most suitable food source for artificial breeding of C. kiangsu. [Ch, 4 fig. 1 tab. 17 ref.]
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Objective  As a factor affecting photosynthesis, light quality can influence the accumulation of secondary metabolites in plants. Cyclocarya paliurus is a medicinal and edible multifunctional plant unique to China, and the active substances (such as triterpenoids) in its leaves can promote and improve human health. The objective of this study is to investigate the effects of light quality on biomass and the accumulation of triterpenoids in C. paliurus leaves from different families to provide reference for environmental selection during the seedling stages and further development of health care products.  Method  Taking 1-year-old seedlings of C. paliurus as materials, four families (Muchuan 31, Anji 1, Jinzhongshan 6, Jinzhongshan 7) and four different light qualities (white light, blue light, green light and red light) were selected to examine the effects of different treatments on biomass, leaf triterpenoid content and yield per plant.  Result  Light quality and genetic factors had significant effects on biomass, triterpenoid content and yield in C. paliurus leaves (P＜0.05). Compared with white light treatment, other light quality treatments significantly reduced total biomass accumulation of C. paliurus (P＜0.05), but there was no significant difference between blue light treatment and white light treatment in Anji 1 family(P＞0.05). The total triterpenoid content in C. paliurus leaves was the highest under white light treatment in Anji 1 and Muchuan 31 families, followed by blue light. Red light treatment significantly increased the content of unique triterpenoid individuals in C. paliurus leaves(P＜0.05). Under white light treatment, the plants with higher level of leaf biomass accumulated more triterpenoids than those under blue and green light treatments.  Conclusion  Proper light quality treatment can be used to increase the contents of target compounds (e.g. triterpenoids) in medicinal plants. [Ch, 1 fig. 8 tab. 27 ref.]
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Objective  With the changes of main mineral element contents in the annual growth cycle of the Paeonia ostii ‘Feng Dan’ measured, the current study is aimed at an analysis of the fertilizer requirement of and nutrient diagnosis for the oil peony.  Method  With ‘Feng Dan’ (eight years old), an oil peony cultivar selected as the study subjects, the mineral elements content of roots, stems and leaves were measured across the annual growth cycle of the oil peony.  Result  The content of P in roots, stems and leaves, and the content of N in roots and leaves decreased gradually as the growth cycle of the peony proceeds, while the changes of K and Mg vary from part to part. The content of Fe was significantly more than any other trace elements in the roots, stems and leaves, and increased first and then decreased across the growth cycle. All of the trace elements, except for Cu, have showed first an increase and then a decrease in content in the roots. As the process of fruit development advanced, the content of N increased, with the content of K in fruit pods and P in seeds displaying a trend of decrease, increase and decrease. The changes of mineral elements in roots, stems and leaves of the peony showed different degrees of correlation across the peony’ s growth cycle, with N、P、K、Fe and Mn closely related to most of the other mineral elements. The same mineral elements displayed different correlations with vegetative organs and reproductive organs.  Conclusion  Throughout one growth cycle, the oil peony ‘Feng Dan’ has a large demand for N and P from the leaf-growth stage to the current bud stage, and N and P fertilizers should be applied before the leaf-growth stage; and there is a large demand for N, P and K during the fruiting period, and it is recommended to apply N, P and K fertilizer after the flowering of the peony. Fe fertilizer should be applied before the budding stage (early March) while B and Zn fertilizers should be applied during the seed development stage from May to July to meet the demand of ‘Feng Dan’ plants for these three microelements. [Ch, 7 tab. 36 ref.]
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Objective  In view of the inconspicuous characteristics of poplar(Populus) scab and mosaic disease, this paper is aimed to propose a method to improve the disease recognition accuracy by means of the pre-treatment of the original image set.  Method  Firstly, the contour of the blade was extracted employing the improved Canny operator edge detection method combined with Hoss Transformation so as to remove the disturbance of the image background. After that, the contrast limited adaptive histogram equalization was adopted to reduce the impact of local illumination unevenness. Thirdly, the OTSU segmentation algorithm with adaptive threshold was used to extract leaf lesion images. At last, the binarized images with lesion and the leaf lesion images were fed into the Alexnet which consists of 5 convolutional layers, 3 full-connection layers, 650 000 neurons and over 60 million learning parameters.  Result  Both groups came back with a significantly higher recognition accuracy rate than that of the the original image experiment group (93.56% and 98.05% VS 88.77%). The hybrid method proposed in this paper could help completely extract the images of the main body of the blade with different backgrounds and effectively avoid the background interference of the target blade. And the adaptive histogram equalization algorithm with limited contrast helped in dealing with the uneven light produced by natural environment and reducing the interference of reflective factors like reflected light.  Conclusion  The pre-treatment of the images of the above-mentioned diseases has significantly improved the recognition accuracy, and is highly recommended in future tasks. [Ch, 8 fig. 1 tab. 22 ref.]
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During their short growth period, most Brassicaceae plants have some light-green or golden-colored mutants, named as yellow mutants, either naturally grown or induced physically or chemically. Such mutants, with intuitive phenotypes, such as shortness, low chlorophyll content and suppressed photosynthesis usually result in the reduction of yield, thus considered as harmful. In the past two decades, the phenomenon of yellowing mutation has attracted an increasing amount of attention from scholors with the research results applied in the study of plant chloroplast structure and chlorophyll metabolism. This review, with a brief introduction to the common types, phenotype characteristics, chloroplast ultrastructure, photosynthetic pigments and photosynthetic properties of yellowing mutants in Brassicaceae plants, is aimed at a discussion of the genetic characteristics and molecular mechanism of the yellowing mutation in the hope of providing a theoretical basis for the study of leaf color mutations and selection of new varieties in Brassicaceae plants. [Ch, 52 ref.]
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Objective  The present study is to analyze the vegetation changes in areas with severe soil erosion on the Loess Plateau since the implementation of forestry ecological projects such as the Three-north (northwest, north and northeast) Shelterbelts and Conversion of Farmland to Forests, so as to provide basis for formulating reasonable ecological restoration and management countermeasures.  Method  Taking Ansai District of Yan’an City in Shaanxi Province as an example, the vegetation coverage in 2000 and 2017 was estimated by pixel dichotomy based on Landsat TM/OLI image, and topographic differentiation characteristics were analyzed in combination with altitude, slope and slope direction.  Result  (1)Vegetation coverage significantly increased from 24.98% in 2000 to 53.34% in 2017. (2)The proportion of vegetation coverage with extremely significant increase in the study area accounted for 44.70%, which was concentrated along rivers. (3)In 2000, the vegetation coverage gradually decreased with the increase of altitude. In 2017, the vegetation coverage increased first and then decreased with the increase of altitude. In 2000 and 2017, the vegetation coverage increased first and then decreased as the slope increased, and reached its maximum value at the slope of 25°−35°. The order of vegetation coverage from large to small with the change of slope direction was shady slope, semi shady slope, semi sunny slope, and sunny slope. (4)When the altitude was less than 1 300 m and the slope was 15°−35°, flat land, shady and semi shady slopes had good water and heat conditions, with easy vegetation recovery and the largest proportion of high vegetation coverage area.  Conclusion  The vegetation in Ansai District showed a trend of improvement from 2000 to 2017, with differences under terrain conditions such as altitude, slope, and slope aspects. Ecological restoration countermeasures should be formulated based on local conditions. [Ch, 2 fig. 6 tab. 27 ref.]
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Objective  This paper is aimed to explore the phenotypic and diversity of ornamental pomegranate and provide theoretical basis for the identification and evaluation of ornamental pomegranate resources in China.   Method  With 24 ornamental pomegranate cultivars selected, an investigation was conducted of their 13 ornamental features such as plant form, branch type, flower color, flower size, number of petal and number of petaloid stamens with an analysis of the diversity. Then, based on these indexes, principal component analysis and cluster analysis were carried out, while the ploidy and C-value of 24 cultivars were determined by flow cytometry(FCM).  Result  (1) The ornamental pomegranate varieties were rich in phenotypic diversity, the morphological diversity index of quantitative trait (1.715) was greater than that of qualitative trait (1.148), and the coefficient of variation of the number of petaloid stamens and petals was 117.59% and 78.86%, respectively, indicating that the increasing number of petals and stamen petalization were the breeding directions of ornamental pomegranate. (2) The variation trend of diversity index of petalized stamen number and petal number was not consistent with that of the variation coefficient, implying that the variation range was large and the variation distribution was uneven. (3) The characteristic values of the first four principal components were greater than 1.00, and the cumulative contribution rate reached 80.10% while the shape and color of branches, flower size, petal number, petal formation, plant form and flower color were the main factors affecting the phenotype differences of ornamental pomegranate. (4) The 24 ornamental pomegranate cultivars could be divided into three groups with their genetic clustering closely related to flower pattern, color and plant type: orange flower cultivars were much more closely related to pink and white flower cultivars than multicolor flower cultivars and single petal cultivars were closely related to all double petal cultivars and most double petal cultivars, while a small number of double petal cultivars were closely related to proliferation flower cultivars, which was consistent with the mainstream view of flower type evolution. (5) All ornamental pomegranate cultivars were diploids, indicating that pomegranate cultivars were genetically stable.  Conclusion  The phenotypic diversity in ornamental pomegranate was rich, and all the tested cultivars were diploid. [Ch, 1 fig. 8 tab. 48 ref.]
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Objective  This research aims to study the effects of exogenous brassinolide (BR) on physiological characteristics of Phyllostachys edulis, and to provide theoretical basis and technical reference for future cultivation and management of Ph. edulis.  Method  The seedlings of Ph. edulis were used as test materials, and 6 kinds of brassinolide solutions with different concentrations[0(ck), 0.050 0, 0.010 0, 0.005 0, 0.001 0, 0.000 5 mg·L−1] were set up through hydroponic culture experiment to compare the differences in the growth characteristics, photosynthetic pigment, photosynthetic characteristics and antioxidant system of the seedlings.   Result  On the whole, compared with ck, brassinolide with different mass concentrations could promote the growth and development of Ph. edulis seedlings to varying degrees, improve the quality of photosynthetic pigments and photosynthetic capacity, and promote the synthesis of osmotic adjustment substances. Compared with ck, when the mass concentration of brassinolide was 0.005 0 and 0.001 0 mg·L−1, the superoxide dismutase activity of bamboo seedlings increased by 6.7% and 6.1%, respectively, oxidase activity increased by 14.6% and 13.7%, and catalase activity increased by 8.2% and 14.6%, respectively. The mass fraction of soluble protein increased by 31.5% and 31.2%, and the mass fraction of starch increased by 17.3% and 16.9%, respectively. However, compared with 0.005 0 and 0.001 0 mg·L−1 treatment, brassinolide treated with mass concentration of 0.050 0, 0.010 0 and 0.000 5 mg·L−1 had no significant effect on antioxidant capacity and osmotic adjustment ability of Ph. edulis seedlings.  Conclusion  Brassinolide can improve the photosynthetic capacity and stress resistance of Ph. edulis seedlings, and promote nutrient growth. The best concentration of brassinolide is 0.005 0−0.001 0 mg·L−1.[Ch, 5 tab. 42 ref.]
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Objective   In order to clarify the control effect of different chemical insecticides on the larvae of the Melanotus cribricollis, a virulence test was carried out on the larvae stage for the present study.   Method   With 5.0% phoxim granules, 0.5% fipronil powder and 20.0% chlorantraniliprole suspension selected and mixed into sand and bamboo forest soil in a 1∶2 ratio with 5 concentration gradients, to observe the mortality rate of M. cribricollis after 24 hours in contrast with a control group where water was sprayed without any insecticides.   Result   The three selected chemical insecticides all have certain control effects on M. cribricollis, with the control effect from strong to weak: 5.0% phoxim＞0.5% fipronil＞20.0% chloranthrene Benzoamide. It was found that the 5.0% phoxim has the best control effect, with an LC50 of 0.190 0 g·kg−1, followed by 0.5% fipronil, with an LC50 of 0.950 0 g·kg−1, and 20.0% chlorantraniliprole which has the weakest control effect with a LC50 of 1.820 0 g·kg−1.   Conclusion   With control effectiveness, toxicity and control costs taken into consideration, 5.0% phoxim Phosphorus granules and 0.5% fipronil are suitable for the control of bamboo forest pests M. cribricollis, yet with the need to further explore the application methods and relevant technologies of forest chemicals. [Ch, 2 tab. 27 ref.]
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Objective  With succinic acid of fatty acids, cinnamic acid and vanillic acid sdanders of phenolic acids, three allelochemicals extracted from Pontederia cordata rhizomes used both alone and jointly.  Method  This paper is aimed at an investigation of the effects of organic acids on the growth of Microcystis aeruginosa.  Result   (1) The growth of M. aeruginosa could be inhibited by succinic acid, cinnamic acid and vanillic acid either solely or jointly, with 92.78% as the inhibition rate achieved with the employment of 100 mg·L−1 succinic acid and cinnamic acid for seven days; (2) when used alone, cinnamic acid demonstrates the strongest inhibition ability with succinic acid and vanillic acid following behind, yet when used jointly, the inhibition ability weakens in the following order: succinic acid + cinnamic acid ＞ cinnamic acid + vanillic acid ＞ succinic acid + cinnamic acid + vanillic acid with vanillic acid weakening the inhibition effect of succinic acid and cinnamic acid on the growth of M. aeruginosa to a certain degree; (3) when succinic acid was combined with phenolic acid (cinnamic acid or vanillic acid), cinnamic acid was combined with vanillic acid or the three organic acids combined, their inhibition effect on M. aeruginosa was enhanced; (4) the combination of fatty acid and phenol acidification either in the same kind or among different kinds can enhance the effect of algal inhibition.  Conclusion  The three allelochemicals extracted from the rhizome of P. cordata might have good algae inhibition effect and the combined action of various allelochemicals might be the main mechanism of P. cordata inhibiting cyanobacteria bloom. Therefore, succinic acid, cinnamic acid and vanillic acid have the potential to be developed as algal inhibitors. [Ch, 2 fig. 2 tab. 26 ref.]
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Objective   This study aimed to determine the effects of different proportions of biochar and compost from Bos grunniens waste as well as the polyacrylamide (PAM) on nutrient leaching in desertified soil. [ Method ] Experiment were conducted in the laboratory by using soil column leaching method. All of treatments were divided into two groups, with and without PAM. Additionally, each group include four treatments, Bos grunniens biochar only, Bos grunniens biochar: Bos grunniens compost equal to 1∶1, bos grunniens compost only and the control treatment.   Result   1) In general, the application of biochar or compost can enhance soil nutrients, and the effect of combined application of biochar fertilizer is significantly better than that of single application of biochar or compost. 2) Compared with the control group, the mixed application of biochar and compost (1∶1, w/w) with a rate of 3% of soil weight can significantly increase the soil pH and make the soil become weak alkalescent: the organic matter content increased by 530% with the addition of biochar and compost, the total nitrogen concentration increased by 255%, with the nitrate nitrogen concentration improved by 24.1% and the total and available phosphorus contents increased by 120% and 78% respectively, with no significant impact on the ammonium nitrogen content, though. 3) The addition of PAM can effectively reduce the leaching loss of exogenous nutrients with the total nitrogen leaching rate decreased by 9.6% in the presence of biochar and compost and the total phosphorus decreased by 7.1%.   Conclusion   The application of biochar and compost products with the addition of PAM can effectively increase the soil nutrient content while reducing nutrient seepage. [Ch, 8 fig. 1 tab. 38 ref.]
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Objective  This study aims to investigate the purification capacity for nutrients in polluted water and the yield of tuber starch of three common tuberous aquatic plants, and estimate the feasibility and potential risk of starch resource utilization.  Method  Purification efficiency of Iris pseudacorus, Canna indica and Calla palustris for polluted water body was compared using hydroponic experiment, and three replicates were set for each group. No plant treatment was used as control group. Removal efficiency of ammonium nitrogen, total nitrogen and total phosphorus in water was investigated. The contents of nitrogen and phosphorus in plant roots, stems, leaves and tubers were analyzed. The content of starch and heavy metals including Cu, Zn, Cr and Pb in plant tubers were measured.  Result  When initial concentrations of ammonium nitrogen and total phosphorus were 7.37−7.53 and 0.41−0.45 mg·L−1, concentrations of ammonium nitrogen, total nitrogen and total phosphorus in plant treatment groups decreased to 0.01−0.07, 0.61−0.91, and 0.025−0.031 mg·L−1 respectively after 20 days of treatment, which met the Class Ⅲ standard for surface water environmental quality (GB 3838−2002). The starch extracted from tubers of I. pseudacorus, C. indica and C. palustris was 61.3, 14.1 and 64.0 g·kg−1, respectively. Starch yields of these plant species were 14.3, 1.2 and 2.6 kg·m−2 respectively in the 100 m2 trial plot. The tuber could accumulate heavy metals. As initial concentrations of Cu2+, Zn2+, Cr3+ and Pb2+ in water were 2.01−2.08, 2.56−2.87, 0.22−0.26, and 0.24−0.26 mg·L−1, the contents of Cu, Zn, Cr and Pb in tuber starch of I. pseudacorus were 10.30, 46.7, 12.03, and 1.74 mg·kg−1, respectively and those of C. indica were 12.68, 44.67, 8.15 and 1.32 mg·kg−1, respectively, while those of C. palustris were 19.28, 66.91, 9.63 and 3.97 mg·kg−1, respectively.  Conclusion  The three tuberous aquatic plants can effectively purify nutrients such as nitrogen and phosphorus, and recover a considerable amount of starch. However if heavy metals coexist in the polluted water, plant tubers are not recommended for resource utilization. [Ch, 4 fig. 17 ref.]
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Objective  The aim is to explore the aluminum tolerance of Hydrogena strigosa and H. longipes tissue culture seedlings, so as to lay a foundation for the application of aluminum resistant plants and the utilization of special acid soil resources.  Method  The effects of different concentrations of AlCl3 (0, 25, 50, 100, 200 mg·L−1) on the growth and physiological characteristics of H. strigosa and H. longipes tissue culture seedlings were studied.  Result  Under low concentration of aluminum stress (25, 50 mg·L−1), the growth of H. strigosa was normal and similar to that of the control group, while the growth of H. longipes was inferior to that of the control group. Under the medium and high concentration of aluminum stress (100, 200 mg·L−1), the growth of tissue culture seedlings was significantly reduced, and the average root length and root volume were lower than those of the control group, indicating that aluminum stress inhibited both the aboveground and underground parts of Hydrangea. With the increase of aluminum stress concentration, the chlorophyll mass fraction of H. strigosa increased at 50 mg·L−1, while the chlorophyll mass fraction of H. longipes decreased, which indicated that H. strigosa promoted chlorophyll synthesis under low aluminum stress, and H. longipes inhibited chlorophyll synthesis under aluminum stress. The content of malondialdehyde in H. strigosa and H.longipes decreased first and then increased. The catalase and peroxid activities increased continuously. The activities of superoxide dismutase were lower than those of the control group, but the difference was not significant. The proline mass fraction of H. strigosa was lower than that of the control group under the treatment of 25 mg·L−1, and higher than that of the control group under other aluminum concentration treatment. The proline mass fraction of H. longipes under aluminum stress was higher than that of the control group.  Conclusion  Hydrangea can make positive growth and physiological responses under aluminum stress, and different species of Hydrangea have different aluminum tolerance. In sum, H. strigosa and H. longipes are resistant to low concentration of aluminum.[Ch, 2 fig. 3 tab. 24 ref.]
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Objective  This research aims to examine the effects of different nitrogen application levels on nutrient decomposition of Cinnamomum migao litter leaves.  Method  In January 2017, the litter leaves of the medicinal plant C. migao were taken as the research object. The leaves were washed, air dried and put into decomposition bags, 10.00 g each. Nitrogen treatments were designed as ck(0 g·m−2·a−1), N1(5 g·m−2·a−1), N2(15 g·m−2·a−1), and N3(30 g·m−2·a−1), and there were three repetitions for each treatment. The samples of litter leaves were collected in March, May, July, September and November, respectively. The quality and nutrient contents of the leaves were measured, and the dynamic effects of nitrogen deposition on nutrient release from the leaves were analyzed.  Result  At the end of litter decomposition experiment, the mass loss rate of litter leaves in all nitrogen application groups was lower than that of ck, the residue rate of litter was higher than that of ck. The difference between N2 and ck was not significant, but the difference between N2 and N3 was significant (P＜0.05). The time needed for 95% decomposition of ck, N1, N2 and N3 was 2.973, 3.626, 3.285 and 3.671 a, respectively. In the leaves of all treatments, the content of C decreased and the content of total N increased first and then decreased, while the content of total P and total K was similar, which decreased at the initial stage of decomposition, then increased as a whole, and finally stabilized. The residual rates of C, total P, total K in the leaves decreased, while the residue rates of total N increased first and then decreased. The residual rate of C in each nitrogen treatment was significantly higher than that of ck (P＜0.05). With the passage of time, the residue rate of N, which increased first and then decreased in ck treatment, showed an overall upward and then downward trend in each nitrogen application treatment. C/N ratio of each nitrogen application group was lower than that of ck in the whole decomposition process, and there was a significant difference between the early decomposition stage and ck (P＜0.05).  Conclusion  Nitrogen addition is not conducive to the decomposition and nutrient release of litter leaves. The more nitrogen is applied, the more obvious the inhibition of decomposition is.[Ch, 4 fig. 1 tab. 33 ref.]
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Objective   Magnetic gel balls are new adsorbents which can efficiently remove pollutants and can be reused. Therefore, it is necessary to prepare a new type of magnetic gel ball.   Method   Magnetic particles (MNP) prepared by the ion co-precipitation method were used as carries for silanization reaction to synthesize magnetic nanoparticles (AM) with amino terminals. A novel magnetic composite gel ball (SA@AM) containing amino, hydroxyl and carboxyl multifunctional groups was prepared by coating sodium alginate (SA) on the surface of magnetic particles with electrostatic effect. Fourier transform infrared spectroscopy (FTIR), elemental analyzer, X-ray diffractometer (XRD), scanning/transmission electron microscope (SEM/TEM), and vibrating sample magnetometer (VSM) were used to characterize the product, and the adsorption properties of the products for heavy metal ions were studied.   Result   The target functional composite gel ball (SA@AM) successfully prepared was of paramagnetic magnetite crystal type, and the size of the SA@AM gel ball was 1.5−2.0 mm. The magnetization values of MNP, AM, SA@AM were 13.8, 13.4, and 6.85 A·m2·kg−1, respectively. Adsorption experiments showed that the maximum adsorption capacity of heavy metal Pb2+ by SA@AM was 105.82 mg·g−1, and the adsorption mechanism was more in line with the Langmuir isothermal adsorption model. Repeated adsorption-desorption experiments showed that the removal rate of Pb2+ by SA@AM was more than 76%.   Conclusion   The new sodium alginate magnetic composite gel ball has excellent adsorption capacity for heavy metal ions Pb2+, and the magnetic gel ball has good regeneration properties. [Ch, 10 fig. 1 tab. 25 ref.]
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Objective   The objective of this study is to further analyze the genetic diversity, genetic relationship and parental identification of Hippeastrum rutilum cultivars at molecular level.   Method   The SCoT marker system of H. rutilum was screened by orthogonal design method, and genetic diversity and genetic relationship of 41 cultivars were analyzed.   Result   (1) The optimum reaction system of SCoT markers for H. rutilum (20 μL) included DNA 40 ng, primer 0.1 μmol·L−1, MgCl2 2.0 mmol·L−1, dNTPs 0.4 mmol·L−1 and rTaq DNA polymerase 0.75 U (1 U=16.67 nkat). (2) 77 polymorphic bands were obtained from 41 H. rutilum cultivars by 12 SCoT primers, and the average polymorphic band ratio was up to 86.52%. The genetic similarity coefficient between H. rutilum cultivars was 0.292 3−0.834 3, indicating that the 41 cultivars had high genetic diversity and wide genetic range. (3)UPGMA(unweighted pair-group method with arithmetic means) cluster analysis showed that the SCoT marker clustering of H. rutilum had significant correlation with flower color, but not with the petal type. At genetic similarity coefficient of 0.420 0, the 41 cultivars were divided into two groups. The first group had both double and single petal cultivars. The first group was divided into four subgroups, among which those with similar flower colors were clustered into one group. In subgroup d, the single-petal, white ‘Hydrangea’ (No. 20) and red ‘Miracle’ (No. 22) were the possible parents of double-petal, orange-red and white multicolor flowers (No. 21 ‘Yingchun’). The second group was mostly multicolor flowers.   Conclusion   SCoT marker technique can be effectively applied to genetic diversity analysis and identification of possible parents of H. rutilum cultivars. [Ch, 6 fig. 4 tab. 21 ref.]
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Objective  With the optimization of tower layout and time sequence in the process of construction, this paper is aimed at the promotion of the construction efficiency of tower networks in forest regions.  Method  With W Forest Farm in the suburbs of Beijing chosen as the testing spot and features of watchtower network construction such as spatiality, periodicity and dynamicity taken into consideration, efforts were made to figure out a near-optimal layout design built employing Greedy algorithm on the basis of Maximum monitoring area model(Max-MAM) established with the vertex method. Meanwhile, with such a design, on the basis of DAMACSTM which was built employing the dynamic multi-attribute entropy weight method, the optimal time sequence of construction was figured out.  Result  38 optional points extracted adopting the vertex method, with the optimal layout achieved by Max-MAM, \begin{document}${\overline {P}_6} = \left\{ {{a_6},{a_{29}},{a_{36}},{a_{12}},{a_{26}},{a_{18}}} \right\}$\end{document}, the monitoring coverage of the watchtower network was maximized (about 71.47%) while with the optimal time sequence of construction achieved with DAMACSTM, a29＞a26＞a12＞a6＞a36＞a18, the comprehensive benefits are maximized.  Conclusion  Two models of Max-MAM and DMACTSM proposed in this paper, can adjust and figure out the optimal time sequence of construction and when combined with GIS, are conducive to the achievement of the optimal layout of watchtower networks. And the optimal time sequence of construction helps maximize the comprehensive benefits in aspects like the increase in the monitoring area, the traffic, the slope, and existing structures. [Ch, 6 fig. 3 tab. 28 ref.]
[Abstract](50) [HTML](4) [PDF](2)
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Objective  This study aims to investigate the effects of liquid ammonia treatment (LAT) pretreatment on the hydrolysis resistance of biomass and the enzymatic hydrolysis rate of lignocellulosic biomass.  Method  Four different types of lignocelluloses biomass, namely wheat straw (Triticum aestivum), alfalfa (Lotus corniculatus), sorghum straw (Sorghum bicolor), and their mixture (mass ratio 1:1:1), were pretreated by LAT method, and the effect of LAT on their chemical structure changes was studied by using thermo gravimetric analysis (TGA), Fourier transform infrared spectrometer (FTIR), X-ray diffractometer (XRD), and scanning electron microscope (SEM). Then, the effect of pretreatment temperature and enzymatic hydrolysis time on the enzymatic hydrolysis conversion rates of glucan and xylan in the four raw materials was investigated.  Result  LAT had a significant effect on the chemical structure of biomass materials. After this pretreatment, the relative content of glucan, xylan, and arabinan in four types of lignocelluloses biomass slightly decreased. The relative content of O and H decreased because some functional groups containing O and H dropped off. The crystallinity decreased slightly, while the surface pore structure significantly increased, and the availability of enzymes in the chemical structure of biomass increased. The optimum pretreatment temperature of wheat straw and mixture was 90 ℃, while that of alfalfa and sorghum straw was 110 ℃. The enzymatic hydrolysis rates of glucan and xylan increased with the increase of enzymatic hydrolysis time. Among the four types of lignocelluloses biomass, the highest enzymatic hydrolysis rate of glucan obtained at the optimal enzymatic hydrolysis condition was wheat straw, followed by the mixture, sorghum straw, and alfalfa. The enzymatic hydrolysis rate of xylan ranging from large to small was sorghum straw, wheat straw, the mixture, and alfalfa.  Conclusion  LAT can improve the enzymatic hydrolysis efficiency of lignocellulosic biomass, especially that of wheat straw and sorghum straw. [Ch, 8 fig. 2 tab. 24 ref.]
[Abstract](46) [HTML](3) [PDF](2)
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Objective  Comparing the combustibility of fresh bamboo leaves in gardens, in order to protect bamboo forest.  Method  Taking 5 common flammable woody plants as control, the moisture content, mass per unit area, absolute line rate, absolute area loss rate, absolute mass loss rate, relative line rate, relative area loss rate and relative mass loss rate of 17 species' fresh bamboo leaves in Kunming were measured and calculated. The combustibility of bamboo leaves was evaluated by factor analysis and systematic clustering.  Result  All the fresh bamboo leaves of 17 species were inflammable, and the order of combustibility from large to small was as follows: Neosinocalamus affinis, Bambusa ventricosa, Fargesia yuanjiangensis, Schizostachyum funghomii, B. sinospinosa, B. textilis, B. multiplex, Dendrocalamus semiscandens, Chimonocalamus pallens, Phyllostachys nigra var. henonis, B. distegia, Ph. nigra, D. bambusoides, D. hamiltonii, D. giganteus, B. intermedia, B. surrecta.  Conclusion  10 of them were highly flammable and 7 were relatively flammable. [Ch, 1 fig. 6 tab. 25 ref.]
[Abstract](47) [HTML](3) [PDF](2)
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Objective  With the phenotypic diversity of male Torreya grandis populations explored and superior male individuals initially screened, this paper is aimed to provide a reference for the scientific configuration of superior pollinator trees so as to improve the actual yield and quality of T. grandis ‘Merrillii’.  Method  With 121 single plants selected from 5 natural male populations in T. grandis, an analysis was conducted of 10 phenotypic traits including single leaf weight, leaf shape index, weight of single male cone, cone shape index, percentage of pollen yield and pollen vitality, etc to study variation in phenotype, based on which superior male individuals were selected.  Result  (1) There were no significant differences (P＞0.05) between populations in all the traits except leaf length and percentage of pollen yield (P＜0.05), but there were significant differences in all 10 traits among individuals within each population, indicating that variation within a population is the main sources of phenotypic variation in male T. grandis and larger than that among populations, which means that artificial selection should be based on the selection of individuals. (2) Among the 10 phenotypic traits, coefficients of variation for male cones were larger than those for leaves with 42.36% and 34.13% as the coefficient of variation for the pollen vitality and pollen yield respectively, which indicates that the selection of superior male individuals should be based on the traits of male cones. (3) 36 superior early, interim and late flowering individuals were screened out according to traits of male cones, which could be used as reference for breeding and plantation in the future.  Conclusion  The phenotypic traits of male T. grandis demonstrate more significant genetic diversity within the populations, and the focus should be laid on the choice of superior individuals within populations in the attempt at the establishment of later genetic improvement strategy of T. grandis while cone shape index, percentage of pollen yield, pollen vitality are important phenotypic indexes for the primary selection of superior individual. [Ch, 1 fig. 7 tab. 26 ref.]
[Abstract](51) [HTML](3) [PDF](3)
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Objective  With the effect of foliar spraying of zinc (Zn) on leaves growth and mineral elements of pecans (Carya illinoensis) explored, the study is aimed to provide scientific basis for the fertilizer control of fruit trees.  Method  Using 6-year-old ‘Pawnee’ pecans as the research material under field conditions, a field experiment was conducted with 3 types of zinc fertilizers, such as EDTA-Zn, zinc sulfate (ZnSO4·7H2O), zinc nitrate [Zn (NO3)2·6H2O)] sprayed at 3 levels of concentrations (50, 100, 150 mg·L−1Zn) in terms of 10 treatments (with 0 mg·L−1Zn as control). Treatments were replicated three times in a randomized complete block design to measure the growth parameters (leaf length and width and area, rate of water content, specific leaf weight, tree height and diameter) and leaf mineral elements [nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), zinc (Zn), iron (Fe), manganese (Mn), copper (Cu)]. These parameters were initially evaluated with the employment of principal component analysis (PCA) and weight subordinate function (WSF).  Result  The leaf growth parameters and tree height and diameter increased to a certain extent with the increased concentration. The leaf length, width, area, specific leaf weight increased by 26%, 37%, 25%, 17% with the 150 mg·L−1 of zinc nitrate treatment respectively, which was significantly higher than that with other treatments (P＜0.05). With the increased concentration, the N, K, Zn, Mn contents of pecan leaves increased and the P, Fe content decreased while the Ca and Mg contents first increased and then decreased. As was shown in the correlation analysis, the length, width, N, K were significantly and positively correlated (P＜0.05) to Zn in leaves while the coverage, Ca, Mn were significantly and positively correlated (P＜0.01) to Zn in leaves.  Conclusion  Foliar spraying of zinc has significantly improved the leaf growth of pecans (P＜0.05) and increased the accumulation of mineral elements in leaves. Thus, it was suggested that 150 mg·L−1 of zinc nitrate or 100 mg·L−1 of zinc sulfate or 50 mg·L−1of Zn-EDTA could be used for foliar spraying of zinc fertilizers in pecans. [Ch, 2 fig. 4 tab. 30 ref.]
[Abstract](85) [HTML](2) [PDF](3)
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Objective  This study aims to optimize the culture conditions of Cd-tolerant Pseudomonas TCd-1 based on response surface methodology.  Method  Taking the basic fermentation conditions as the control, and the absorbance D(660) value of the strain as the evaluation index, the single factor test was carried out to determine the best carbon source, nitrogen source, and inorganic salt species of the culture medium components. The Plackett-Burman test design was used to evaluate the influence of 8 factors on the growth of the strain, including beef extract, yeast powder, magnesium chloride, culture temperature, initial pH, inoculation quantity, culture time, and rotation speed. The best combination of significant factors was obtained by the steepest climbing test. The culture conditions of TCd-1 were optimized by combining the box Behnken design test and response surface analysis.  Result  The best carbon source, nitrogen source, and inorganic salt of the strain culture medium components were beef extract, yeast powder, and magnesium chloride. The significant factors affecting the growth of the strain were yeast powder, culture temperature, and initial pH. The optimized culture conditions based on response surface methodology included beef extract 0.5%, yeast powder 1.0%, magnesium chloride 0.5%, pH 6.3, temperature 33 ℃, inoculation rate 1.25%, rotation speed 160 r·min−1, and culture time 24 h.  Conclusion  According to the optimal conditions, the D(660) value of the optimized bacterial solution is 67.07% higher than that of the control after repeated experiments, which is consistent with the predicted value of the model, indicating that the optimized conditions could significantly promote the growth of the strain and achieve the desired goal.[Ch, 1 fig. 6 tab. 26 ref.]
[Abstract](74) [HTML](5) [PDF](5)
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Objective  Due to the differences in growth cycles and wood characteristics, the market price of rosewood species including some nationally protected species varies sharply. To prevent fraud and better protect tree tree species, this paper is aimed at the accurate identification of redwood specie.  Method  With 376 samples of 7 species of rosewood collected in the actual test by the National Forestry and Grassland Administration Center for Quality Supervision and Testing of Wood and Bamboo Products (Kunming) selected as the research subject, a convolutional neural network model for automatic recognition of redwood is proposed using the computer algorithm to expand the number of samples.  Result  This method can automatically identify features that fit with the model of classification and recognition, making it more convenient to utilize. Compared with traditional methods, it secures a more accurate identification with an average identification accuracy of 99.4%.  Conclusion  The self-built convolutional neural network can effectively identify redwood species. Although it takes a long time to achieve the parameter adjustment and train than VGG16 and other transfer learning methods, it shows stronger competence of generalization. It is proved that the self-built model is superior to the transfer learning model when applied in redwood recognition. [Ch, 7 fig. 4 tab. 23 ref.]
[Abstract](91) [HTML](2) [PDF](8)
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Cucurbitaceae is one of the important plant families in agricultural production, most of which are annual vines. The key morphological marker of Cucurbitaceae plants is tendril. This paper summarizes and analyzes the main research results on tendrils of Cucurbitaceae plants, and puts forward a prospect for future research. The present researches on tendrils of Cucurbitaceae horticultural crops mainly focus on the following aspects: (1) the origin of tendril; (2) the key gene regulating tendril development; (3) the genes specifically or highly expressed in tendrils; (4) the endogenous hormones regulating tendril development; (5) the influence of external environment on tendril development. The main conclusions are as follows: tendrils of Cucurbitaceae horticultural crops are identified as abnormal organs of lateral branches, and the key gene regulating tendril is TCP1. Tendril tissue-specific or high-level genes are mainly involved in morphological development, tropism, auxin polar transport, calcium ion transport, glutamate metabolism, lignin metabolism, which are closely related to tendril generation, development and coiling. Hormone (auxin, gibberellin) and environment factors (light, temperature and water) have been reported to affect tendril development, but the specific molecular mechanism remains unknown. Future research on tendrils of Cucurbitaceae horticultural crops should focus on the analysis of the upstream and downstream gene network of TCP1 to improve the regulatory effect of hormones and external environment on tendrils. Based on the mature gene editing technology, it will be beneficial to explore the molecular regulatory network of tendrils of Cucurbitaceae horticultural crops and develop tendril-less breeding design. [Ch, 2 fig. 32 ref.]
[Abstract](84) [HTML](5) [PDF](2)
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[Abstract](111) [HTML](4) [PDF](5)
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Objective  With an analysis of the genetic variation of wood basic density and fiber morphology of Pinus massoniana among seed sources and clones within seed sources, this paper is aimed to provide high quality genetic material for the breeding and improvement of P. massoniana.  Method  Fifty clones from five seed sources of P. massoniana clones selected from 34-year-old experimental forests of different seed sources in Laoshan Forest Farm, Chun’an County, Zhejiang Province, were investigated to determine the wood basic density, fiber length, fiber width and fiber length-width ratio. Then variance analysis, correlation analysis and genetic parameter estimation were conducted to reveal the genetic variation while superior individuals were selected from the 50 P. massoniana with the employment of Independent Selection Standard Method.  Result  The results of ANOVA revealed that there were significant or extremely significant differences in the basic density and fiber morphology of the wood among seed sources and clones within seed sources. The variation of clones within seed sources with the variance components ranging from 19.37% to 28.26% was the main source of wood basic density, fiber length and fiber length-width ratio. The variation of seed sources with the variance components (45.57%) was the main source of fiber width. There is a significant phenotypic and genetic negative correlation between basic densities of wood and fiber length and fiber length/width, but the correlation coefficient is not high and the basic densities of wood is not related to fiber width. The fiber morphological indexes showed significant positive genetic correlation in the juvenile age and mature age, while the wood basic density showed no significant correlation in the juvenile age and mature age. A total of 12 clones of P. massoniana with excellent wood properties were selected.  Conclusion  More attention should be paid to the selection of superior trees within seed sources in the attempt to improve the three traits of wood basic density, fiber length and fiber length-width ratio. On the other hand, the fiber width can be better improved through the choice of seed sources. In view of the significant correlation of fiber morphology indexes between juvenile and mature timber, they can be selected as reference indexes in the early stage. [Ch, 4 tab. 25 ref.]
[Abstract](103) [HTML](2) [PDF](3)
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Objective  To provide a theoretical basis for solving salt damage of rose, the effect of exogenous melatonin (MT) on the physiological characteristics of rose seedlings (Rosa chinensis ‘Old Blush’) with the NaCl stress was investigated.  Method  90 d rose cutting seedlings were watered with 0, 5, 10 and 20 μmol·L−1 melatonin of exogenous melatonin solution respectively for 5 days before they were treated with 20 d 200 mmol·L−1 NaCl while the control group was treated with water to study the alleviation of exogenous melatonin on rose seedlings under salt stress with the physiological and biochemical indexes determined after the salt treatment.  Result  With the exposure to salt stress, rose seedlings with the alleviation of exogenous melatonin of different concentrations present a significant decrease in electrical conductivity and mass molar concentration of malondialdehyde(P＜0.05) while a significant increase in the content of soluble protein, proline and ascorbic acid (P＜0.05). In particular, the activity of superoxide dismutase(SOD), catalase(CAT) and peroxidase(POD)(P＜0.05)has been significantly promoted, which helps enhance the scavenging activity of reactive oxygen species(ROS) under salt stress.  Conclusion  The exogenous melatonin treatment could enhance the activity of antioxidant enzymes and increase the osmotic substance content to avoid lipid peroxidation and improve rose salt tolerant ability. [Ch, 3 fig. 21 ref.]
[Abstract](86) [HTML](2) [PDF](2)
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Objective  This research aims to study the age structure and spatial pattern of Phoebe sheareri population in Tianmu Mountain, so as to better protect the population and provide basis for forest management.  Method  Based on the survey data of 1 hm2 (100 m×100 m) of evergreen broad-leaved forests in Tianmu Mountain of Zhejiang Province, the age structure of dominant species P. sheareri population was analyzed. According to the diameter at breast height(DBH), the population was divided into five diameter classes: diameter class 1 (1.0 cm≤DBH＜2.5 cm), diameter class 2 (2.5 cm≤DBH＜10.0 cm), diameter class 3 (10.0 cm≤DBH＜20.0 cm), diameter class 4 (20.0 cm≤DBH＜30.0 cm), diameter class 5 (DBH≥30.0 cm). The point pattern method was used to analyze the spatial distribution pattern of P. sheareri and spatial correlation of individuals of different diameter classes.  Result  (1) 68.95% were young individuals in diameter class 1 and diameter class 2, 23.71% in diameter class 3, 7.34% in diameter class 4 and diameter class 5. The survival curve of the population was close to Deevey type I, belonging to the growth-oriented development model. (2) The individuals of diameter class 1, diameter class 2, diameter class 3 and diameter class 4 were mainly distributed in clusters, and with the increase of research scale, the aggregation was more significant, and diameter class 5 was mainly of random distribution. (3) There existed a close relationship between diameter classes, displaying a dominant positive correlation. In small scale observation, diameter class 1 and diameter class 4 were negatively correlated in the scale of 0−5 m, diameter class 3 and diameter class 4 were negatively correlated in the scale of 0−8 m, and diameter class 3 and diameter class 5 were negatively correlated in the scale of 0−4 m. All other diameter individuals were positively correlated. From the large-scale observation, there was a significant positive correlation between individuals of different sizes in P. sheareri population.  Conclusion  The population of P. sheareri in Tianmu Mountain belongs to the growth-oriented development model, and each diameter class is distributed in clusters. The relationship between different diameter classes is close, displaying a dominant positive correlation. [Ch, 5 fig. 2 tab. 24 ref.]
2020, 37(4): 611-622.   doi: 10.11833/j.issn.2095-0756.20190525
[Abstract](387) [HTML](56) [PDF](154)
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Objective  The objective of this research is to study the chemical properties and enzyme stoichiometry of soil under different proportions of Larix gmelinii forests.  Method  The investigated L. gmelinii forests were classified into six groups according to its volume proportion in the community (70%, 75%, 80%, 85%, 90%, 95%), and its soil samples were monitored for the nutrient content and biochemical properties in 0−5 cm soil layers and 5−20 cm soil layers.  Result  Among the five enzymes analyzed, the activity of acid phosphatase was the highest, and the mean value of 0−5 and 5−20 cm soil layers were 463.74 and 312.91 nmol·g−1·h−1. In 0−5 cm soil layer, the activity of leucine aminopeptidase (LAP) was promoted by the increase of L. gmelinii proportion, and the leucine aminopeptidase activity of L. gmelinii community with 95% proportion significantly increased by 57.44% and 59.40%, compared with that of L. gmelinii community with 75% and 85% proportion. The proportion of L. gmelinii in the community also affected the chemometric characteristics of soil enzymes. When the proportion of L. gmelinii reached 95% in 5−20 cm soil layer, the ratio of nitrogen-acquiring enzyme to phosphorus-acquiring enzyme was much higher than that of L. gmelinii communities with the proportion of 80% and 85% (P95%-80%=0.02, P95%-85%=0.02). However, the ratio of carbon-acquiring enzyme to nitrogen-acquiring enzymewas lowest in forest community with 95% proportion of L. gmelinii. There existed a complex correlation between soil enzyme activity and soil nutrient content, which also changed with the increase of soil depth. In 0−5 cm soil layer, soil pH negatively correlated with the activities of glucosidase (BG), and acetylglucosaminidase (NAG) (PpH-BG=0.01, PpH-NAG=0.03). In the 5−20 cm soil layer, there existed a positive correlation between soil total nitrogen (TN) content and the activities of leucine aminopeptidase (LAP) and NAG (PLAP-TN=0.02, PNAG-TN=2×10−4), and a negative correlation between acid or alkaline phosphatase (AP) and soil total phosphorus (TP) content (PAP-TP=0.02). Through the redundancy analysis of the above variables, it was found that the enzymatic stoichiometry was greatly influenced by soil pH in 0−5 cm layer, while in 5−20 cm layer it was mainly affected by the mass fraction of soil total nitrogen and available nitrogen.  Conclusion  The proportion of L. gmelinii in the mixed coniferous and broad-leaved forest in warm temperate zone is an important biological factor for regulating soil nutrient dynamics, and its regulation largely relies on the activity and stoichiometric characteristics of soil enzymes. [Ch, 4 fig. 4 tab. 41 ref.]
2020, 37(4): 623-630.   doi: 10.11833/j.issn.2095-0756.20190565
[Abstract](105) [HTML](65) [PDF](41)
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Objective  The objective is to explore distribution characteristics and seasonal variations of soil microbial biomass carbon (MBC) content at different succession stages of coastal wetlands in Jiangsu Province, and to reveal its main influencing factors.  Method  Five typical succession stages of coastal wetlands in Jiangsu were selected as the research objects, including coastal mudflats, Spartina auglica wetland, Suaeda glauca wetland, Phragmites australis wetland, and Robinia pseucdoacacia forest. The distribution characteristics of soil MBC at the different succession stages, the effects of vegetation succession, soil layer and season on MBC, the relationship between soil MBC and soil physical and chemical properties were analyzed. The key factors affecting soil MBC in coastal wetlands were discussed.  Result  Soil MBC content ranged from 116.91 to 326.18 mg·kg−1, with a significant difference between different succession stages, but the distribution trend was not consistent with the succession direction. The highest was Sp. auglica, followed by P. australis, coastal mudflats, Su. glauca, and R. pseucdoacacia. In 0−10 cm soil depth, soil MBC content in Sp. auglica wetland was significantly higher than that of other succession stages in four seasons. Soil MBC content at different succession stages first increased and then decreased with variation of seasons in the three soil layers, reaching its peak in autumn but lower in spring or winter. Soil MBC in coastal wetlands was significantly affected by seasons and succession stages, among which the seasonal factors had the largest impact, accounting for 32.29%. There existed a significant positive correlation between soil MBC content and total organic carbon, total nitrogen and soil moisture content, but a significant negative correlation with soil pH.  Conclusion  Vegetation succession and seasons are the main factors affecting the distribution and dynamic characteristics of soil MBC in coastal wetlands, among which seasonal factors have the greatest influence, and soil organic matter, moisture content and pH are the key factors that directly affect soil microbial activity. [Ch, 1 fig. 2 tab. 35 ref.]
2020, 37(4): 631-638.   doi: 10.11833/j.issn.2095-0756.20190462
[Abstract](281) [HTML](79) [PDF](24)
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Objective  To establish a scientific fertilization system for Zizyphus jujuba ‘Lingwuchangzao’, the current study is aimed to figure out the correlation of soil, leaves and fruit nutrients with the quality of the above mentioned jujube.  Method  With the soil, leaves and fruit nutrients of 5 Z. jujuba ‘Lingwuchangzao’ as the study subjects, by using the multiple linear stepwise regression analysis the relationship between fruit quality with the soil fertility and leaf nutrients was established.  Result  The soil fertility properties of different planting bases were significantly different, and Mn was generally lacking in planting bases. The longitudinal diameter of fruit was negatively correlated with the soil total K, the fruit hardness and the fruit N content. The fruit titration acid content was positively correlated with the content of soil available K, leaf P and fruit N, but negatively correlated with the content of fruit Fe. The content of fruit N was positively correlated with the content of soil organic matter, leaf Fe and fruit Zn, but negatively correlated with the content of soil Se. The K content of fruit was negatively correlated with the effective Fe content of soil, but positively correlated with the total P content of soil. The content of Zn in fruits was positively correlated with the content of available K in soil, Zn in leaves and N in fruits.  Conclusion  The application amount of organic fertilizer and trace element fertilizer should be increased in the planting bases of Z. jujuba ‘Lingwuchangzao’, especially that of Mn, while that of Fe should be reduced. [Ch, 11 tab. 24 ref.]
2020, 37(4): 639-645.   doi: 10.11833/j.issn.2095-0756.20190509
[Abstract](323) [HTML](67) [PDF](18)
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Objective  The discharge of agricultural non-point source pollutants such as phosphorus has become one of the major causes for the eutrophication in Taihu Lake. Riparian vegetation buffer strips can reduce non-point source pollution from agricultural area into water through absorption and interception. The riparian vegetation strips were built on gentle slopes to study the efficiency of retaining phosphorus so as to provide a scientific basis for mitigating the pollution of agricultural non-point sources in Taihu Lake.  Method  Taking the buffer strip of plantation along the bank of Taihu Lake as the research object, the interception effects of riparian plantation buffer strips with different widths (15, 30, 40 m), densities (400, 1 000, 1 600 trees ·hm−2 ), plantation types (Populus × euramericana ‘Nanlin 95’ plantation, Taxodium hybrid ‘Zhongshanshan’ plantation and ‘Nanlin 95’-‘Zhongshanshan’ mixed plantation) and ages (3, 4, 5, 6 a) on total phosphorus (TP) and dissolved phosphorus (DP) in surface runoff water were studied to determine the suitable structure of vegetation buffer strips.  Result  The 30 m wide buffer strips had the optimal effect on intercepting phosphorus in runoff water, and the TP interception rate was the highest at 30 m, 77.30%. The interception rate of DP increased with the increase of buffer strips width but there existed no significant difference between different widths of buffer strips in terms of DP interception rate (P＞0.05). The stand density of riparian buffer strip with good interception effect on TP and DP in runoff water was 1 000 trees ·hm−2, and the interception rate was 84.29% and 93.25%, respectively. The ‘Nanlin 95’ plantation could intercept 82.37% TP in runoff water while the interception rate of ‘Nanlin 95’- ‘Zhongshanshan’, the mixed plantation on DP was a little higher than that of ‘Nanlin 95’ plantation, but the interception rate of DP in the buffer strips of different plant compositions was not significant different (P＞0.05). The effect of buffer strips on interception of DP in runoff water was better than that on TP. With the increase of plantation age, the interception rate of phosphorus in runoff water increased gradually (P＜0.01), and reached the highest at the age of 5.  Conclusion  The 30 m wide buffer strips can meet the requirement of pollution interception, and the ‘Nanlin 95’ plantation buffer strips have good interception effect on phosphorus. Besides, the buffer strips have stronger phosphorus interception capacity at a young age. [Ch, 5 fig. 1 tab. 40 ref.]
2020, 37(4): 646-653.   doi: 10.11833/j.issn.2095-0756.20190531
[Abstract](274) [HTML](57) [PDF](22)
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Objective  This research aims to explore the water consumption characteristics of Eucalyptus urophylla at night and its driving factors, and provide data support for improving the estimation accuracy of water consumption in large scale eucalyptus forests.  Method  Using thermal dissipation probe(TDP) technique, E. urophylla, a common eucalyptus from Leizhou Peninsula, was chosen as the research object to continuously observe its nocturnal sap flow and simultaneously measure the main environmental factors such as atmospheric temperature, humidity, rainfall and photosynthetically active radiation. The characteristics and the driving mechanism of sap flow at night were discussed in depth.  Result  The results indicated that the average water consumption contribution rate of E. urophylla at night during the observation period was 6.62%, and the first half of the night consumed significantly more water than the second half (P＜0.05). The nocturnal flow rate was significantly higher in the rainy season than in the dry season (P＜0.05). The average nocturnal flow rate was extremely significantly higher on sunny days than on rainy days (P＜0.01). The nocturnal water consumption contribution rate in the dry season is 1.4 times that in the rainy season. Nocturnal flow rate was significantly and positively correlated with vapor pressure deficit(P＜0.01)during the dry and rainy seasons, and the fitting equation was of high statistical significant. However, the coefficient of determination was only 0.37 and 0.35 for the dry season and the rainy season, respectively. Meanwhile, there was an extremely significant positive correlation between the nocturnal water consumption and the daytime transpiration (P＜0.01), and there was a power function relationship with a determination coefficient of 0.33.  Conclusion  Nocturnal water consumption accounts for a small proportion of the total transpiration volume. However, if nocturnal sap flow is fully ignored, total water consumption of the E. urophylla plantation ecosystem based only on the daytime sap flow can be underestimated. Nocturnal transpiration and trunk hydration together drive the E. urophylla’s nocturnal water consumption. [Ch, 4 fig. 2 tab. 27 ref.]
2020, 37(4): 654-663.   doi: 10.11833/j.issn.2095-0756.20190521
[Abstract](326) [HTML](52) [PDF](23)
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Objective  The objective is to study the effects of volatile organic compounds (VOCs) from three evergreen plants on air microorganism inhibition and air purification.  Method  The composition and content of VOCs in Myrica rubra, Vatica mangachapoi, Camellia sinensis in single tree and open field were analyzed using thermal desorption system/gas chromatography/mass spectrometry (TDS-GC-MS) technique. The effect of VOCs on airborne microorganism was investigated by natural sedimentation method, and the number of air anion was measured.  Result  The main VOCs of M. rubra were α-oxalene, parsley alcohol, rolene, limonene and nonaldehyde, in which terpenes accounted for 78.5% of the total. The main VOCs of V. mangachapoi were acetyl acetate, octyl butyrate, cis-3-hexenol, pinocarvone, nonanal, decanal, and octanal, in which ester compounds accounted for 54.1% of the total. Acetyl acetate, octyl butyrate, methyl salicylate, nonanal, decanal, limonene were the main VOCs of C. sinensis, and ester compounds accounted for 40.8% of the total. The VOCs in open space were benzene, accounting for 74.2% of the total. The VOCs in M. rubra garden were benzene and terpene, accounting for 54.8% and 35.6%, respectively. The VOCs in V. mangachapoi garden were benzene and terpene, accounting for 35.4% and 52.2%, respectively. The VOCs in C. sinensis garden were benzene and terpene, accounting for 50.1% and 36.5%, respectively. The daily average number of air anion in M. rubra garden, V. mangachapoi garden, C. sinensis garden, and the open space was 2 559.2, 2 660.0, 1 878.4, 1 078.8 per cubic centimeter, respectively. In M. rubra garden, V. mangachapoi garden, and C. sinensis garden, daily average bacterial inhibition rate was 45.5%, 48.7% and 39.3%, respectively, daily average inhibition rate of fungi was 39.0%, 35.8% and 34.6%, respectively, and that of actinomycetes was 42.3%, 42.2% and 39.7%, respectively.  Conclusion  Plant VOCs can inhibit the growth of airborne microorganism, promote the formation air anion and improve the air quality. [Ch, 5 fig. 2 tab. 38 ref.]
2020, 37(4): 664-672.   doi: 10.11833/j.issn.2095-0756.20190398
[Abstract](211) [HTML](87) [PDF](18)
Abstract:
Objective  The objective of this research is to reveal the photosynthetic characteristics and the development of photosystem of the stem of Phyllostachys edulis.  Method  Blue-greengel electrophoresis (BN-PAGE) was used to analyze the thylakoid membrane proteins in stems and leaves, and the changes in pigment content and the 77 K low temperature fluorescence emission spectrum were measured.  Result  The content of chlorophyll and carotenoid in stems was significantly lower than that in leaves (P＜0.01), and with the development of stems, the pigment content increased significantly. The core complex of PSⅡ in the thylakoid membrane of stems and leaves was relatively complete and there were more light-catching pigments. PsaA/B and PsaD subunits were mainly isolated from PSI core complex in leaves and the stem base, and PsaA/B was obtained from the middle of stem, but no PsaA/B was found at the top of stem. There were two obvious main peaks at 685 and 745 nm in the 77 K low temperature fluorescence emission spectrum of leaves and stems, and six maximum values in the fourth derivative spectrum, which were mainly the fluorescence emission peaks of the core complex of PSⅡ and PSⅠ, and the shoulder peak caused by the emission fluorescence peak of the PSⅡ peripheral light catching antenna (LHC Ⅱ), PSⅡ inner peripheral light catching antenna (CP47), PSⅡ inner peripheral light catching antenna (CP43), PSⅠ reaction center complex (RCI), and PSI light catching antenna (LHC Ⅰ). The characteristic emission peak of LHC Ⅱ and PSⅡ core complex at the top of stem had obvious blue shifts compared with that of leaves.  Conclusion  The core complex of PSⅡ in stems of Ph. edulis has been formed. With the development of stems, the bamboo shoot coat gradually falls off, the pigments are synthesized in large amount, the inner antenna proteins CP47 and CP43 and the peripheral light-catching complex are formed gradually. Meanwhile, the PSⅠ core proteins PsaA and PsaB begin to form after the stems are exposed to light, and the core complex of PSⅠ is gradually assembled and synthesized. [Ch, 4 fig. 2 tab. 45 ref.]
2020, 37(4): 673-682.   doi: 10.11833/j.issn.2095-0756.20190456
[Abstract](258) [HTML](77) [PDF](19)
Abstract:
Objective  The aim is to investigate the response of stem height, ground diameter, leaf area, root weight and biomass accumulation of the seedlings of Quercus variabilis to the coupling of water and fertilizer, and to establish optimal combination of irrigation and fertilization.  Method  The four-factor-five-level quadratic regression general rotatable central composite design(RCCD) was employed to establish the regression model of each index and soil moisture (W), nitrogen (N), phosphorus (P) and potassium (K), with an analysis conducted of the main effect, monofactor and coupling effect of each factor on growth.  Result  (1)With the variance analysis of the stem height, ground diameter, leaf area, root weight and biomass, it was found that there is a significant divergence in the treatment of various factors (P＜0.05) and the growth of seedling 8,16 and18 is the most favorable. (2) The model test results show that W and N have significant positive effect on all 5 indexes, P has no significant effect on ground diameter, K has no significant effect on any indexes, and there is a decrease of the main effect: W＞N＞P＞K. (3) In terms of monofactor effect, it was shown that all the indexes presented a trend of first increase and then decrease with the increase of fertilizer application, in the path of a parabola. There was a gradual growth of the seedling with the increase of W before the a drop occurred in the growth rate. (4) With the anlaysis of the coupling effect, it was found that W×N has significant positive effects on stem height, root weight, biomass and leaf area, W×P has significant positive effects on stem height, ground diameter, root weight and biomass, W×K has significant positive effects on biomass, and N×P has significant positive effects on root weight, leaf area and biomass, N×K has significant negative effects on the ground diameter and the coupling effect between water and fertilizer is greater than that between fertilizers.  Conclusion  In conclusion, the water and fertilizer demand in the seedling stage of Q. variabilis is W＞N＞P＞K, and suitable water and fertilizer ratio can promote the growth of seedlings. Seedlings grow better with conditions of high water, high nitrogen, high phosphorus and low potassium fertilizer. The optimal combination of water and fertilizer regulation was as follows: soil water content was 79% of the maximum field moisture capacity, nitrogen application was 215.3 mg·plant−1, phosphorus application was 46.0 mg·plant−1, potassium fertilizer application was 18.1 mg·plant−1, with seedling height reaching 45.14 cm, ground diameter reaching 4.40 mm, root weight reaching 6.30 g·plant−1,biomass reaching 11.70 g· plant−1, and leaf area reaching 460.83 cm2. [Ch, 3 fig. 2 tab. 30 ref.]
2020, 37(4): 683-692.   doi: 10.11833/j.issn.2095-0756.20190407
[Abstract](243) [HTML](62) [PDF](19)
Abstract:
2020, 37(4): 693-701.   doi: 10.11833/j.issn.2095-0756.20190514
[Abstract](327) [HTML](66) [PDF](17)
Abstract:
Objective  This study aims to indicate the distribution of forest community and species diversity on the gradients of complex environment by classifying and sorting the community of ecological non-commercial forest in Songyang County, Zhejiang Province, and discussing the change law of diversity and interspecific relationship.  Method  Taking 128 monitoring plots as research projects, two-way indicator species analysis (TWINSPAN), canonical correspondence analysis (CCA), species diversity index and interspecific association analysis were used to study the community characteristics of non-commercial forest in Songyang County.  Result  TWINSPAN results showed that the forest community could be divided into 6 types. CCA results demonstrated that the community distribution and types of non-commercial forest in Songyang County showed obvious differentiation on environmental gradient, which was mainly affected by altitude, soil type and slope aspect. The results of multiple comparison of species diversity showed that the Shannon-Wiener index and Simpson index of associations with mixed forest or broad-leaved forest were significantly higher than those of other associations, and the diversity of association dominated by Phyllostachys edulis was significantly lower than that of other associations. Interspecific Association Analysis illustrated that most tree species in sample plots had no significant correlations. The positive and negative correlation ratio was 1.9, indicating the overall stability of the community.  Conclusion  Differential management should be carried out for the non-commercial forest in Songyang County, and mixed and broad-leaved forests should be actively promoted. It is possible to consider different supplementing measures for the non-commercial forests with different site conditions and different stands. The edge control of bamboo forests and community combinations that can adapt to various environments should be properly promoted. [Ch, 4 fig. 3 tab. 37 ref.]
2020, 37(4): 702-709.   doi: 10.11833/j.issn.2095-0756.20190428
[Abstract](278) [HTML](57) [PDF](15)
Abstract:
Objective  This study aims to explore the species composition, structure and characteristics of wild Phoebe and Machilus communities in Yuan’an County, Hubei Province, and improve the distribution record of wild Phoebe and Machilus resources in Yichang area.  Method  The field investigation of the wild Phoebe and Machilus communities in Mingfeng Town, Hualinsi Town and Leizu Town of Yuan’an County was carried out by using quadrat method to record the habitat conditions and species distribution of Phoebe and Machilus plants, and the method of Community Ecology was used for statistical analysis.  Result  (1) There were 2 species of Phoebe and 3 species of Machilus plants in the survey area, including Phoebe neurantha and Ph. faberi in Ph. genera, and M. ichangensis, M. pauhoi and M. ultinervia in Machilus genera. M. pauhoi and M. multinervia were identified as new distribution record species in Yuan’an County. (2) There were 73 species of vascular plants belonging to 35 families and 61 genera, among which 21 families were single genera and single species. The high bud plants had the largest distribution in the community, while the underground and surface buds had the least. The DBH levels of most species were in grade Ⅲ (5.0 cm ≤ DBH＜7.5 cm)and Ⅳ(7.5 cm ≤ DBH＜22.5 cm), with a few species in grade Ⅴ（DBH≥22.5 cm). Shannon-Wiener diversity index H′, Simpson dominance index Ds and evenness index Jsw showed no significant difference among the three townships(P＞0.05), but Margalef richness index R did(P＜0.05).  Conclusion  Yuan’an County is rich in wild Phoebe and Machilus resources, with high species diversity index and reasonable community structure. However, the protection of local wild Phoebe and Machilus resources should be further strengthened. [Ch, 3 fig. 3 tab. 28 ref.]
2020, 37(4): 710-719.   doi: 10.11833/j.issn.2095-0756.20190472
[Abstract](532) [HTML](198) [PDF](32)
Abstract:
Objective  Phyllostachys edulis(Moso bamboo) forest is one of the forest community types that have been expanding in the subtropical region of China in recent 30 years. The spread and invasion of Ph. edulis forests are becoming more and more serious, threatening the vegetation around the Moso bamboo forest. It has become an important problem of forestry ecological construction at present and in the future. The study aim is to know the type and species diversity of natural regeneration community, and their influencing factors after clear cutting of Moso bamboo forest.  Method  This paper is based on the monitoring data of secondary communities formed by natural regeneration after clear cutting of Moso bamboo forest in Mount Tianmu, TWINSPAN analysis was used to classify the natural regeneration communities, The differences of α diversity among different communities were compared, the influence of environmental factors was analyzed by redundancy analysis.  Result  (1)Species and types of natural regeneration community are varied after clear-cutting of Moso bamboo forest, can be divided into 11 different communities. There were significant differences in alpha diversity among different communities. (2) Through redundancy analysis, it was found that among the three topographic factors of elevation, slope direction and slope, elevation was the main factor that determined the alpha diversity of woody layer and herbaceous layer of natural regeneration community and was significant negatively correlated with it(P＜0.05).  Conclusion  This paper reveals the distribution pattern of community and environmental factors in the early stage of succession and provides theoretical basis for vegetation restoration in the protected area. [Ch, 3 fig. 3 tab. 38 ref.]
2020, 37(4): 720-728.   doi: 10.11833/j.issn.2095-0756.20190498
[Abstract](186) [HTML](55) [PDF](16)
Abstract:
Objective  This study aims to investigate the species composition, biological diversity and structural characteristics of natural secondary forest communities with different restoration ages in the karst area at the head of canal in the middle route of the South-to-North Water Diversion Project, and to understand the vegetation status in the karst area, so as to provide scientific basis for regional vegetation protection and restoration, biodiversity protection and comprehensive management and evaluation of rocky desertification.  Method  Using the research method of “space instead of time”, and taking 6 kinds of natural secondary forests (20, 28, 35, 40, 53, 70 a) in the karst area of Xichuan County as the research object.The tree layer, shrub layer and herb layer were investigated according to the method for forest community survey, and the important value of community species, diversity index, community structure and community similarity coefficient were calculated.  Result  A total of 63 species of vascular plants belonging to 40 families and 58 genera were found in 18 fixed plots of 10 800 m2. With the increase of recovery years, the species richness increased continuously, and most of the increased species belonged to single family, single genus and single species. The species diversity index of each layer showed different characteristics with the increase of recovery years, but the overall trend was slowly rising. Shannon diversity index, Simpson diversity index and Pielou evenness index of tree layer were the highest in P5 plots (recovery time 53 a), and the lowest in P1 plots (recovery time 20 a). Shannon diversity index and Simpson diversity index of shrub layer and herb layer increased slowly. The results of Jaccard similarity coefficient showed that there was a very different level of similarity between plots with different recovery years, and the species composition was quite different. Except for the density, there were significant differences in community average height, coverage, DBH and other structures between 20 and 70 a after restoration (P＜0.05), and there was no significant difference among the others.  Conclusion  Compared with the karst areas in southwest China, the species richness in the karst area at the head of canal in the middle route of the South-to-North Water Diversion Project is relatively low, and Quercus variflora is the dominant species in the communities, with single family, single genus and single species being the majority, and the difference between communities is large. In the later period of vegetation restoration in the karst area, vegetation grows slowly, and the tree height and DBH are mainly concentrated in grade Ⅱ and Ⅲ. [Ch, 2 fig. 5 tab. 34 ref.]
2020, 37(4): 729-736.   doi: 10.11833/j.issn.2095-0756.20190464
[Abstract](403) [HTML](160) [PDF](112)
Abstract:
Objective  This research aims to analyze the plant community structure of Qianwangling Park in Lin’an District of Hangzhou City, Zhejiang Province, and evaluate its ecological benefits.  Method  Taking Qianwangling Park as the research object, the structure of 32 plant communities in the park was investigated, and the i-Tree model was used to evaluate the ecological benefits of community including energy conservation, carbon dioxide absorption, air quality improvement and rainwater interception.  Result  (1) There were 1 613 trees in the community, belonging to 39 families 62 genera and 74 species. The community structure was mainly of the multi-layer type, dominated by the landscape style of the mixed forest of needles and broads. (2) The annual ecological benefit of the community was 208 588.16 yuan·a−1, and the average benefit per tree was 129.25 yuan·plant−1·a−1, among which the benefits of energy conservation, carbon dioxide absorption, air quality improvement and rainwater interception were 48 188.80, 98 447.36, 4 019.84 and 57 932.16 yuan·a−1, accounting for 23.10%, 47.20%, 1.93% and 27.77% respectively. The highest total value of ecological benefits reached 12 777.60 yuan·a−1, found in sample L21 (Cinnamomum camphora+Magnolia grandiflora-Camellia japonica community), accounting for 6.13%. This community had the highest benefits in saving energy, absorbing carbon dioxide and intercepting rainwater. The mixed community contributed the most to ecological benefit values, accounting for 35.47%. (3) The deciduous broad-leaved and coniferous trees had higher average benefits per plant, and deciduous broad-leaved trees had more advantages in energy conservation, CO2 absorption, air quality improvement and rainwater interception.  Conclusion  The ecological benefit of plant community in Qianwangling Park is mainly determined by the number of tree species, growth type and average diameter at breast height. The coniferous and broad-leaved mixed community has obvious advantages in ecological benefit value. [Ch, 2 fig. 4 tab. 23 ref.]
2020, 37(4): 737-744.   doi: 10.11833/j.issn.2095-0756.20190538
[Abstract](1982) [HTML](234) [PDF](30)
Abstract:
Objective  Alien invasive plants have huge negative impacts on the biodiversity and ecological security of native ecosystems. This research aims to understand the situation of invasive plants in Putuoshan Island, Zhejiang Province.  Method  Sample surveys were conducted in different areas of Putuoshan Island. According to the weighted statistics of distribution area, coverage and the Zhejiang invasion level, the harm degree and invasion grade of various invasive plants were assessed, and the key harm areas, and prevention and control areas of invasive plants in Putuoshan Island were determined.  Result  There were totally 47 alien invasive species of plants, belonging to 36 genera of 21 families, and all of them being herbaceous. Moreover, out of total observed invasive species, 80.85% (38 species) were found to be native of America. 23 species of plants were in moderate or serious harm, and 22 species could be seen in plants belonging to class Ⅰ and class Ⅱ degree.  Conclusion  Hilly mountains, desolated land and coastal wetlands are important ecological regions of Putuoshan Island where control of alien invasive species is much needed. Since the present situation of invasive plants in Putuoshan Island is serious, it is necessary to increase publicity about bad impacts of invasive species, carry out joint programs to control their spreading, and strengthen the quarantine inspection of alien plants into the island. Additionally, adequate risk assessment of non-native plants should be carried out before their intentional application to prevent and control any invasive hazards in future. [Ch, 1 tab. 31 ref.]
2020, 37(4): 745-751.   doi: 10.11833/j.issn.2095-0756.20190487
[Abstract](194) [HTML](67) [PDF](18)
Abstract:
Objective  This study aims to explore the effects of sanitation cutting of the diseased pine trees infected by Bursaphelenchus xylophlius on the stand structure of pure Pinus massoniana plantation and provide a reference for the management of P. massoniana invaded by B. xylophlius.  Method  Field plots were selected of both a pure P. massoniana plantation infected by B. xylophlius and its neighbouring plantation uninfected to be investigated in Lin’an, Zhejiang, China.  Result  After 12 years of sanitation cutting, compared with the uninfected pure P. massoniana plantation, it is shown that the importance values of P. massoniana significantly decreased from 100.00% to 38.41%. The stand diameter distribution followed an inverse J-shaped curve. In terms of height stricture, single storied stand changed into multi-storied stand. The individual size inequality significantly increased. The distribution pattern of trees changed from uniform distribution to random distribution. The competitive index of trees significantly increased, and that of trees at 6 cm diameter class was the highest.  Conclusion  The sanitation cutting accelerated the succession speed of the infected pure P. massoniana, with significant changes in several stand structure indicators and the single-storied even-aged pure P. massoniana stand succeeded by the mixed multi-storied uneven-aged P. massoniana and broad-leaved trees stand. [Ch, 2 fig. 4 tab. 18 ref.]
2020, 37(4): 752-760.   doi: 10.11833/j.issn.2095-0756.20190486
[Abstract](573) [HTML](80) [PDF](16)
Abstract:
Objective  To provide theoretical guidance for the management of the plantation of Pinus massoniana, a wood widely used in the south, this study is aimed at the establishment of a high-efficiency diameter-height Model.  Method  With 4 284 P. massoniana plants from 82 sample plots in central Guizhou Province as the study subjects, 6 generalized nonlinear models were selected to fit the diameter-height relationship. After the determination of the optimal number of hidden layer nodes, repeated training was conducted to establish the BP neural network-based model of diameter-height relationship for P. massoniana plantation.  Result  Among the 6 generalized nonlinear models, the model that fits the best is Korf function (R2=0.650) while the two hidden layers for BP neural network model were suitable for P. massoniana plantation with 1∶2∶1 as the appropriate model structure (number of input layer nodes∶number of hidden layer nodes∶number of output layer nodes) was and the model prediction accuracy reaching 0.717.  Conclusion  The generalized nonlinear model can fit the diameter-height relationship of P. massoniana plantation pretty well, yet in comparison, the BP neural network works better in that it’s not reliant on empirical models and has better fitting accuracy for the high R2 yet lower root mean squared error. [Ch, 5 fig. 5 tab. 35 ref.]
2020, 37(4): 761-768.   doi: 10.11833/j.issn.2095-0756.20190443
[Abstract](783) [HTML](297) [PDF](22)
Abstract:
Objective  With ash and pond sediment as main raw material, the purpose of this research is to prepare biological ceramics with efficient nitrogen and phosphorus removal for treatment of polluted aquaculture water by immobilizing effective microorganism (EM) community.  Method  The optimal proportion of fly ash ceramsite was determined by isothermal adsorption test. The fly ash ceramsite was fixed with EM and treated for 6 days in simulated aquaculture wastewater with ammonia nitrogen, total nitrogen and total phosphorus concentrations of 50, 55 and 20 mg·L−1.  Result  Under the preheating temperature of 300 ℃ and the firing temperature of 1 100 ℃, when the mass ratio of fly ash ceramsite was m (fly ash)∶m (active sediment)∶m (limestone powder)∶m (iron powder)=50∶40∶5∶5, the modified fly ash ceramsite immobilized EM had the best purification effect on nitrogen and phosphorus in the simulated aquaculture wastewater. After 6 days, the maximum removal rates of ammonia nitrogen, total nitrogen and total phosphorus were 98.67%, 93.80% and 45.35%, respectively.  Conclusion  Fly ash ceramsite itself has a certain adsorption and purification capacity of nitrogen and phosphorus. After the immobilization of ceramsite with EM, water purification effect can be enhanced. [Ch, 5 fig. 4 tab. 24 ref.]
2020, 37(4): 769-777.   doi: 10.11833/j.issn.2095-0756.20190463
[Abstract](515) [HTML](171) [PDF](15)
Abstract:
2020, 37(4): 778-786.   doi: 10.11833/j.issn.2095-0756.20190477
[Abstract](364) [HTML](67) [PDF](108)
Abstract:
Objective  Reasonable scale determination is the key to the research of landscape pattern and ecology and has become one of the research focuses in landscape ecology and geography. Hence, the present research is focused on the granularity effect of landscape index at the county scale and appropriate granularity range of landscape index which is of great significance to the analysis of landscape pattern changes.  Method  First, with the landscape distribution map of Susong County, Anhui Province in 2017 was used as the data, an analysis was conducted of the granularity effect of each landscape index in the granularity range of 20−500 m from the two levels of type and landscape with the appropriate granularity range selected. Then, the fitting function was used to reveal the variation features of different landscape pattern indexes with the increase of granularity. Lastly, the optimal spatial granularity value of landscape pattern changes in Susong County was determined by the results of the precision evaluation model of landscape area loss.  Result  (1) The landscape indexes had a certain spatial granularity effect and most of them were highly predictable; (2) Landscape total area index, average area fractal dimension, average shape index, Simpson diversity index and Simpson evenness index demonstrated low response sensitivity to spatial granularity; (3) There were four different types of granularity effect curves of the landscape index: monotonically decreasing, monotonically increasing, no change, and complex change and their inflection points were mainly occurred at 70 and 200 m; (4) Power function was the main function upon the favorable fitting of the landscape index granularity effect curve.  Conclusion  The suitable grain size range landscape pattern change was 100−110 m in Susong County, Anhui Province, and the optimal grain size value was 100 m. [Ch, 3 fig. 1 tab. 27 ref.]
2020, 37(4): 787-792.   doi: 10.11833/j.issn.2095-0756.20190510
[Abstract](278) [HTML](47) [PDF](9)
Abstract:
Objective  The out-layer of bamboo culm has adverse effects on bamboo’s subsequent processing. It is essential to optimize the technology to ensure product quality.  Method  The single factor experiment was applied to determine the optimum conditions of turning parameters in turning technology for removing out-layer of bamboo culm. Using the effect of removing bamboo green of bamboo culm as the dependent variable, Box-Behnken Design experiment was adopted to examine the effects of turning parameters including bamboo tube rotation speed, feed rate and cylinder pressure. Experimental data were analyzed using Design Expert 12 software, multivariate quadratic regression equation mathematical model between dependent variable and independent variables was established to determine the optimum technical parameters.  Result  When the bamboo tube rotation speed was 60 r·min–1, the feed rate was 0.25 m·min–1, and the cylinder pressure was 0.20 MPa; there was a maximum effect of removing bamboo green of 66.97%.The above-mentioned process conditions were used to carry out the actual verification, and the obtained effect of removing bamboo green was 65.36%. The error with the theoretical prediction value was –2.37%.  Conclusion   The model was reasonable and could be used for the prediction of actual effect of removing bamboo green. [Ch, 5 fig. 6 tab. 13 ref.]
2020, 37(4): 793-800.   doi: 10.11833/j.issn.2095-0756.20190449
[Abstract](287) [HTML](74) [PDF](13)
Abstract:
As an environmental-friendly wood physical modification method, wood heat treatment can not only improve the dimensional stability and biological durability but also effectively improve wood color, and is widely used in the functional improvement of fast-growing wood. Some representative research achievements on heat treatment technology are discussed. The traditional processes of wood heat treatment are summarized, and the future research is prospected. The present research on wood heat treatment mainly focuses on the following aspects: (1) the influence mechanism of high temperature heat treatment on such properties as wood dimensional stability, color and crystallization; (2) effects of high temperature environment on the content of the main chemical components, the volatile evaporations and degradation process of wood extraction; (3) changes and reactivity of phenolic hydroxyl and surface free radicals in lignin; (4) effects of heat treatment on wood permeability, paint film adhesion and durability. On this basis, the correlation between changes of wood characteristics (mass or surface chromaticity index) before and after heat treatment and heat treatment intensity is further analyzed. The characteristic parameters of wood such as mass loss rate, color difference of treated wood and the ratio of oxygen to carbon elements are important parameters to predict the properties of heat-treated wood. The future research on wood heat treatment should focus on the relation of micromechanical properties at the cell level and the macro-mechanical properties, and the development of catalysts to reduce the energy consumption of wood heat treatment. The biological durability, environmental and mechanical properties of heat-treated wood can be predicted rapidly and accurately based on the content or proportion of the main elements, surface color and other characteristics. On the other hand, the main parameters of heat treatment process are determined by using the prediction model according to the application environment and requirements, which can provide reference for the follow-up study. [Ch, 48 ref.]
2020, 37(4): 801-809.   doi: 10.11833/j.issn.2095-0756.20190478
[Abstract](939) [HTML](346) [PDF](42)
Abstract:
In recent years, the growing contradiction between degradation of soil fertility quality and forestry production has seriously threatened the sustainable development of forestry, the maintenance of soil fertility quality has become very urgent. Aiming at the hot issue of degradation and maintenance of soil fertility quality in plantations, this paper systematically elaborates the evolution trend of soil fertility quality in management of Cunninghamia lanceolata plantations from the perspectives of soil physical property, soil chemical property, soil microorganism, soil enzyme activity and allelopathy. Many studies have shown that degradation of soil fertility quality and continuous decrease of productivity are common problems in C. lanceolata plantations, and the main contributing factor is unsustainable forestry practice. The results of soil fertility maintenance in C. lanceolata plantations are reviewed from such aspects as rotation management, mixed compound afforestation, forest density adjustment, fertility compensation and sustainable forest management. The research on soil fertility quality maintenance in C. lanceolata plantations is prospected. [Ch, 1 tab. 48 ref.]
2020, 37(4): 810-816.   doi: 10.11833/j.issn.2095-0756.20190484
[Abstract](1183) [HTML](420) [PDF](38)
Abstract:
Objective  The induced clustered buds of Cryptomeria fortunei have strong differentiative capacity but insufficient elongation ability. In order to obtain the optimum medium of adventitious bud induction, proliferation, elongation culture and rooting induction, the rapid propagation system of C. fortunei was established.  Method  The annual shoot from 20-year-old C. fortunei were used as explants; the orthogonal test design was used to select the optimum medium. The propagation system of C. fortunei includes induction, proliferation, elongation, rooting and transplant.  Result  (1) Adventitious buds from three clones could be induced on MS, DCR and WPM basic medium supplemented with different combinations of 6-BA, IBA and CH. But the proliferation ability of buds varied significantly among different mediums. When clones were cultured in WPM medium with 1.0 mg·L−1 6-BA and 0.1 mg·L−1 IBA, the induction rate and proliferation coefficient was the highest, which was 100% and 9.13, respectively. (2) When three clones of C. fortunei were subcultured alternately with high concentration hormone and low concentration hormone, the effective shoot growth rate reached 456.87%. (3) The most suitable medium for the C. fortunei rooting was DCR medium with 0.1 mg·L−1 IBA, under which the rooting rate ratio was 100%. (4) The rooted seedlings were transplanted to a mixed matrix with equal vermiculite and peat, after 15−20 days of seedling hardening, and the survival rate was 96.70%. Therefore, the potential propagation ability is 3 865 seedlings per maternal plant per year.  Conclusion  Thus, an efficient propagation technology for C. fortunei was established, which laid a technical foundation for industrialization of improved varieties. [Ch, 1 fig. 5 tab. 23 ref.]
2020, 37(4): 817-822.   doi: 10.11833/j.issn.2095-0756.20190542
[Abstract](231) [HTML](57) [PDF](14)
Abstract:
Objective   To provide rationale for the selection and breeding of natural superior individuals of Torreya grandis, this research is intended to study the inheritance of the growth traits of T. grandis seedlings which are generally used as the rootstock for grafting scions from T. grandis ‘Merrillii’ in production.   Method   With half-sib seedlings of T. grandis openly pollinated in the natural forests as a material, the height, basal diameter and number of branches were measured for two consecutive years while the relevant genetic parameters were fitted and estimated employing conventional linear mixed model (LMM) and generalized linear mixed model (GLMM) so as to calculate the genetic and phenotypic correlation coefficients.   Result   The coefficient of variation of seedling height was greater than that of basal diameter and decreased with the seedling age. Every growth trait parameter displayed a very significant difference among families (P＜0.01) and a relatively high heritability. The heritability of one-year-old seedlings for each parameter was higher than that of two-year-old seedlings and the genetic correlation was greater than that of phenotypic correlation. In terms of genetic gain, the seedling height was bigger than the basal diameter and the number of branches, and the genetic gain of the annual shoot was the highest. The correlation analysis of growth phenotypic traits showed that there was a significant correlation between genotype and phenotype of the same batch seedlings in all the parameters except the number of branches.   Conclusion  Natural T. grandis populations have displayed the great potential for selection and breeding in growth traits. Seed-bearing trees could be selected based on the height of one-year-old seedlings for the purpose of stock cultivation. [Ch, 3 tab. 24 ref.]