2018 Vol. 35, No. 2
Water retention, a most important ecosystem service that is key to water source protection planning, reflects the ability of an ecosystem to keep the water, as well as showing water available for human consumption. To better understand the characteristics of water retention and to better protect the water environment of Liandu District in southwest Zhejiang Province, this study evaluated the quantity and spatial characteristics of its water retention. The assessment was carried out using the InVEST (integrated valuation of ecosystem services and tradeoffs) model. Then a simulation of water retention for Liandu in 2030 was conducted by the CA-Markov Model. The main results showed that from 1994 to 2015, the city area increased by 6.11×104 hm2, the total area of forest increased 1.35×104 hm2, and by contrast, the rocky area decreased 1.91×105 hm2. For the study area the average water retention in 1994 was 69.98 mm, in 2001 was 98.40 mm, in 2008 was 82.36 mm, and in 2015 was 114.01 mm; total water retention in 1994 was 1.11×108 m3, in 2001 was 1.56×108 m3, in 2008 was 1.23×108 m3, and in 2015 was 1.83×108 m3. Overall, water retention increased 62.92%. Underlying surface and climatic features were the two greatest factors affecting water retention with soil hydraulic conductivity, having a standardized coefficient of 0.644, being the most important. Also, a large difference in spatial distribution for different time periods was found. In general, the southern and northern parts of the study area had better water retention with the central parts not as good. The simulation showed that the average water retention of the study area was 112.90 mm, and total water retention was 1.81×108 m3 with the northwest region having a greater water retention potential. Thus, combining the InVEST Model and CA-Markov Model provided a favorable reference for effective management of water retention.
Moso bamboo (Phyllostachys edulis) stands, one of the most economic forest-types in China, possess many advantages over other types, such as rapid growth, wide distribution, and high production. Much research on competition of Moso bamboo, such as intraspecific and interspecific competition, the relationship between biomass and competition, and improvements of competition index, has been conducted, but this study focused on spatial variability and its dynamic analysis of bamboo competition in distance scale dependence, which has been neglected. Based on data collected from 2009-2015 in the Moso bamboo stand of Tianmu Mountain National Nature Reserve of Zhejiang Province, the Hegyi Competition Index (CI) was calculated based on Geographic Information System (GIS). Spatial semivariogram was used to analyze the auto-correlation range of CI and its anisotropy. Also Moran's I and Empirical Bayesian Kriging (EBK) were used to describe dynamic changes in the competitive spatial pattern. Results showed that spatial distribution of CI for Moso bamboo had a significant general global autocorrelation (P < 0.001). Bamboos of the same competitive intensity were distributed evenly. Also, Moso bamboo stands had strong spatial variation due to their structural features. The CI spatial pattern, influenced by micro topography, existing anisotropy, and an extreme climate, reduced spatial heterogeneity and was inclined to be isotropic. The competition range appeared inverse to change in the on-year and off-year growth cycles with the average range being 4.306 m. This range could be used as the distance scale for the basis of determining competition unit radius and for control of the Moso bamboo competitive relationship. Even though Moso bamboo competition increased from off-years to on-years, its competition lessened from on-years to off-years. These research results could provide a reference for adjusting and controlling the competitive relationships in Moso bamboo stand management.
Undergrowth vegetation and soil evolution are essential prerequisites of plantation growth and community structure, which then determine the stability and health of a plant community. To evaluate community succession patterns of plantation ecosystems along with stand age changes, plantation and soil ecosystem changes in forests were analyzed using a spatial sequence approach instead of a temporal sequence. Pinus thunbergii plants in the mid-southern mountainous lands of Shandong Province were the test materials, and plant community structure, understory vegetation, soil physicochemical properties, and microbial community characteristics were determined. Results showed that (1) Soil available P was significantly different for different stand ages (P < 0.05). For different stand ages, soil available K was also significantly different with 30 years being highest and 6 years lowest (P < 0.05). Total N at 50 years was significantly lower than at 6 and 30 years (P < 0.05); whereas, available N at 30 years was significantly higher than at 6 and 50 years (P < 0.05). (2) At different stand ages, soil invertase and cellulase activities were significantly different (P < 0.05) with 30 years being highest and 50 years lowest. Soil urease activity was significantly greater at age 50 than at 6 years and 30 years (P < 0.05) and decreased with the increasing stand age. (3) For soil microbial diversity, the order of change for stand age was 6 year-old > 50 year-old > 30 year-old with Proteobacteria, Actinobacteria, and Acidobacteria having the greatest abundance. (4) The diversity of undergrowth vegetation decreased as stand age increased. These results have theoretical significance in guiding the management of Pinus thunbergii plantation scientifically.
In Beichuan, a severely afflicted area from the May 12, 2008 earthquake, vegetation was severely damaged with numerous secondary disasters. This study aimed to understand recovery of the natural vegetation for different types of disasters of the May 12, 2008 earthquake. Five different types of disasters in Beichuan County were selected, including avalanches (B1), rock fall (B2), debris flow (B3), landslides (B4), and barrier lakes (B5) with one intact forest (ck). A total of 180 quadrats of five different types of disasters in Beichuan, were selected to conduct vegetation investigation, adopting important value, Shannon-Wiener diversity index, Margalef richness index, Hurlbert evenness index and other indexes to be used to evaluate the plant community species composition, structure, species diversity, and similarity of species. Results indicated that (1) secondary disasters had a simple plant community structure, where Compositae and Gramineae herbs were dominant vegetation types, with the number of species being B4 > ck > B5 > B2=B3 > B1. (2) In the secondary disaster area, the dominant species of the tree layer was Alnus cremastogyne, the dominant species of the shrub layer was Debregeasia orientalis, and the dominant species of the herb layer were Miscanthus floridulus, Senecio scandens, and other Compositae plants. (3) For species similarity, the secondary disaster area and intact forest land had strong differences with species similarity coefficients being B4 (0.19) > B5 (0.13) > B2 (0.10) > B3 (0.06) > B1 (0.02). However, many similarities between different secondary disaster areas were found with similarity coefficients between B2, B3, B4, and B5 of about 0.28. In conclusion, the natural recovery and renewal were slower in the five different types of disasters in Beichuan.
To provide a theoretical basis for evaluating the restoration and vegetative allocation of a Robinia pseudoacacia plantation in the Caijiachuan Watershed on the Loess Plateau of western Shanxi Province, this research used the sample survey method to study species diversity of an understory. A R. pseudoacacia plantation was selected as the research object and compared to a Pinus tabulaeformis plantation and a natural secondary forest. This study used Shannon-Wiener index(H'), Simpson index (D) and Pielou evenness index (E) to determine the community α diversity. The β diversity of the community was determined by Whittaker index (βW), Cody index(βC), Routledge index(βR), and the similarity of the community was determined by Jaccard index (q). Results showed (1) 37 understory species in the R. pseudoacacia plantation including 8 shrubs and 29 herbs. Rosaceae was the main contributor to the shrub layer with Compositae and Gramineae the main plants of the herb layer. (2) The α diversity of shrub layer is R. pseudoacacia plantation < P. tabulaeformis plantation < natural secondary forest. The α diversity of herb layer is P. tabulaeformis plantation < R. pseudoacacia plantation < natural secondary forest. (3) The β diversity index between R. pseudoacacia plantation and P. tabulaeformis plantation < β diversity index between R. pseudoacacia plantation and natural secondary forest, the β diversity index of herb layer in R. pseudoacacia plantation > the β diversity index of shrub layer. (4)Among different sample plots of the R. pseudoacacia plantation, the shrub layer showed "medium dissimilarity" accounted for 49.52% of the total and "very similar" accounted for 1.90% of the total, the herb layer was "very similar" accounted for 66.67% of the total, "very similar" accounted for 0.95%, so there was a large difference in R. pseudoacacia plantation, especially in the herb layer. Overall, understory vegetation in the R. pseudoacacia plantation of the Caijiachuan Watershed on the Loess Plateau of western Shanxi Province still had areas for introducing new understory species to help improve species diversity.
To understand the differences and allocation of carbon storage on farmland with afforestation versus abandonment and to provide basic accounting data for forest carbon storage. When farmland through afforestation and abandonment had been restored 14 years respectively, the carbon storage of vegetation, litter, soil were estimated through field investigation and laboratory bioassay. Results showed that (1) biological carbon storage of returning farm to forest was significantly higher than that of abandoned farmland (P < 0.05). The tree layer of returning farm to forest was 2.76 times the abandoned farmland; whereas, the shrub layer and the herb layer were lower than the latter. (2) Soil carbon content for the two rehabilitation approaches decreased with an increase in soil depth. Soil carbon storage on abandoned farmland also decreased with an increase of soil depth. Soil carbon storage from 0 to 80 cm depths for returning farm to forest was in the order of 20-40 cm > 0-10 cm > 40-60 cm > 10-20 cm > 60-80 cm. The soil carbon storage of 0-80 cm deep for returning farm to forest was not significantly different (P > 0.05) from abandoned farmland. (3) Carbon storage for the ecosystem in returning farm to forest was higher than that of abandoned farmland(P < 0.05). Carbon storage of the ecosystem with the two rehabilitation approaches was soil layer > tree layer > litter layer > herb layer > shrub layer. This study showed that during this period the carbon sequestration capacity with afforestation on farmland was better than abandonment.
As an important part of the active soil organic carbon (SOC) pool, microbial biomass carbon (MBC) is the impetus and key to nutrient and energy cycling in the soil ecosystem. To provide important scientific references for forest soil carbon sequestration and greenhouse gas emission in this region, the warming effect on forest soil MBC and dissolved organic carbon (DOC) were determined using an incubation experiment. The content dynamics of MBC and DOC of an evergreen broadleaf forest, a Cunninghamia lanceolata forest, a mixed coniferous and broadleaf forest, and a Cryptomeria fortunei forest in the National Nature Reserve of Fengyang Mountain were studied using an incubation experiment at 10℃, 20℃, and 30℃. Results showed that SOC and DOC in the Cryptomeria fortunei forest were significantly higher (P < 0.05) than other forests; MBC in the mixed broadleaf forest was significantly higher (P < 0.05)than the other forests; and SOC, MBC, and DOC in the Cunninghamia lanceolata forest were significantly lower (P < 0.05). At 10℃, MBC for various stand types declined fast at an early stage and then declined slower. However, DOC rose in the early stage and then declined later. At 20℃, MBC and DOC with various stand types slowly declined. At 30℃, MBC with various stand types rose early but declined later, and DOC quickly declined early and slowly declined later. For the same detection time, MBC for the same stand type was characterized by 30℃ > 20℃ > 10℃; whereas, DOC was 10℃ > 20℃ > 30℃. For the same temperature, MBC and DOC in the evergreen broadleaf forest as well as the mixed coniferous and broadleaf forest declined larger on the whole than in the C. lanceolata forest and the C. fortunei forest after the 56 days of incubation experiment.
To understand how long-term application of edible fungus residue (F) and chemical fertilizers (C) affected soil fertility, nine treatments were established with combinations of three rates of F (0, 50%, and 100%) and three rates of C (0, 50%, and 100%). Each treatment received 3 replicates. The treatment plots were arranged as randominzed blocks design, with plot size of 4 m×5 m. Fractions of soil labile organic carbon (LOC1, LOC2, LOC3) and changes of basic soil fertility parameters were examined through a rice field experiment (2010-2016). Results showed that compared to a single C application, a combined application of F and C had significant (P < 0.05) effect on increasing of the soil carbon pool management index (CPMI), and content of three types of soil LOCs along with their availability (ALCs), rates increase for CPMI by 45.09%, LOCs by 41.77%-53.55%, and ALCs by 11.69%-33.55%. Of the nine treatments, C100F100 was the most effective with a CPMI of 204.95; content of LOC1(oxidized by 33 mmol·L-1 KMnO4) of 1.73, LOC2(by 167 mmol·L-1 KMnO4) of 3.41, and LOC3(by 333 mmol·L-1 KMnO4) of 4.37 g·kg-1; and content of ALC1 of 14.53%, ALC2 of 28.56%, and ALC3 of 43.03%. All three LOCs had significant positive correlations with soil total nitrogen (r1=0.758**, r2=0.711** and r3=0.722** for LOC1, LOC2 and LOC3 respectively), available nitrogen (r1=0.940**, r2=0.930** and r3=0.726** for LOC1, LOC2 and LOC3 respectively), available phosphorus (r1=0.781, r2=0.802 and r3=0.784 for LOC1, LOC2 and LOC3 respectively), available potassium (r1=0.674, r2=0.707 and r3=0.440 for LOC1, LOC2 and LOC3 respectively), and soil organic carbon (r1=0.827, r2=0.774 and r3=0.637 for LOC1, LOC2 and LOC3 respectively). Therefore, LOC1 had most close correlations with SOC and soil fertility changes. Soil LOC was mainly determined by F application; whereas, C was the main nutrient supplier. Consequently, a proper combined application of F and C was favorable to improve soil fertility and rice yield with C50F50 the best treatment in this study.
To accelerate the resource utilization of green waste, this study considered the combination of composting disposed green waste mixed with cow dung by employing Eisenia fetida. After pre-composting green waste for 60 d, seven treatments were prepared for vermicomposting by mixing green waste (pre-composted materials) with cow dung at ratios (dry weight) of 0(T0, without earthworms as a control), 0(T1), 2%(T2), 4%(T3), 6%(T4), 8%(T5), and 10%(T6). Growth and reproductive performance of E. fetida in different treatments were measured after 60 d of vermicomposting with a plant cultivation experiment (Calathea veitchiana) being conducted to estimate the quality and maturity of the final vermicompost. A complete random design with treatments of T0, T1, T2, T3, T4, T5, T6 and 30 replications. At the end of cultivation, five plants were randomly selected from each treatment and were analyzed for the plant growth parameters. Results showed that final products of all treatments with earthworms (T1-T6) were significantly higher (P < 0.05) in nutritional element content and plant growth parameters than T0. Moreover, in comparison with pure green waste treatment (T1), treatments with the addition of cow dung significantly (P < 0.05) increased the rate of growth and reproduction of earthworms, significantly (P < 0.05) accelerated the degradation rate of cellulose and lignin, and significantly (P < 0.05) increased nutrient contents of the final vermicompost product. Moreover, with the addition of cow dung, significantly (P < 0.05) increaseed in microbial population (bacteria, fungi, and actinomycetes) in vermicomposts were recorded. Among treatments T2-T6, T5 and T6 had significantly (P < 0.05) higher fertilizer value for the final product as well as significantly (P < 0.05) higher growth and fecundity of E. fetida. Thus, the combination of both processes (composting + vermicomposting) could be suitable for disposing cow dung and green waste with the green waste mixed with cow dung treatments at rates of 8% (T5) and 10% (T6) improving the efficiency and quality of the vermicompost.
To study the physiological responses of 3-year-old Phyllostachys edulis seedlings to drought stress, heat stress, and synergistic stress, a pot experiment was conducted. Changes of reactive oxygen species (ROS), malondialdehyde (MDA), ascorbic acid, and glutathione concentration, as well as changes in enzyme activity of anti-oxidative enzymes and ascorbate-glutathione (AsA-GSH) cycle in the leaves of Ph. edulis were determined using an artificial simulation method by a spectrophotometer with different levels of drought stress (control check(70.0%-80.0% of field water-holding capacity), light stress(60.0%-70.0% FC), medium stress(40.0%-50.0% FC), and heavy stress(20.0%-30.0% FC)), heat stress (25℃ and 40℃), and synergistic stress. Results showed that the contents of superoxide anion (O2·-) and hydrogen peroxide (H2O2) in leaves of Ph. edulis increased (P < 0.05) compared to ck with drought stress. Anti-oxidant enzyme activities and the ρGSH/ρGSSG ratio increased (P < 0.05) compared to ck with an increase in the degree of drought stress. With moderate drought stress, compared to ck, highly significant differences (P < 0.01) were found for activities of superoxide dismutase (SOD) (1.7 times higher), peroxidase (POD) (1.7 times higher), and the ratio of ρGSH/ρGSSG (0.6 times higher). Compared to ck, MDA increases (1.4 times) were highly significant (P < 0.01), and increases in the activity of SOD, POD, and catalase (CAT), along with the ratio ρAsA/ρDHA were highly significant (P < 0.01) with heat stress. After synergistic stress, compared to ck, ROS increased (P < 0.01), and the degree of membrane lipid peroxidation was enhanced (P < 0.01); meanwhile, the stability of CAT activity was strongest (P < 0.01) increasing steadily compared to ck with an increase in synergism. Also, the ρAsA/ρDHA ratio showed a downward trend; whereas, the ρGSH/ρGSSG ratio was not significant. Thus, the GSH cycle showed stronger resistance to synergistic stress than the AsA cycle suggesting that Ph. edulis seedlings could protect themselves effectively from oxidative damage with a degree of heat, drought, and synergistic stress.
Moso bamboo (Phyllostachys edulis) can complete its growth in a vary short period, called the rapid growth period. To reveal the flow direction of nutrient transport during the rapid growth period and to analyze characteristics of daily variation for bamboo's gas exchange parameter, a Li-6400XT photosynthesis system was used to measure leaves' gas exchange parameter of three-year-old and five-year-old bamboo. Results indicated that:(1) In the early stage of the rapid growth period, light saturation point (LSP) of three-year-old bamboo was higher than five-year-old bamboo. During the middle and later stages of the rapid growth period, however, five-year-old bamboo's light saturation point was overtake three-year-old bamboo. (2) The net photosynthetic rate (Pn) of three-year-old bamboo was not significantly different within the different stages of the rapid growth period (P > 0.05); whereas, five-year-old bamboo's net photosynthetic rates were significantly lower (P < 0.05) in its early stage compared to its middle and later stages. In addition, the net photosynthetic rate was highly correlated to bamboo's age (P < 0.01, r=0.131) and growing stage (P < 0.01, r=0.166). (3) Transpiration rate (Tr) was highly significant and correlated (P < 0.01, r=0.688) to its net photosynthetic rate and different stages of the rapid growth period, but was not significantly correlated to bamboo's age (P > 0.05, r=0.201). (4) Leaf water use efficiency of bamboo was higher (P < 0.01) in the morning than that in the afternoon, and significantly greater (P < 0.01) in the middle period than that in early and later periods. WUE for five-year-old bamboo was also significantly (P < 0.05) than three-year-old bamboo. This study indicated that the process of nutrient and water transfer from grow-up bamboo to young bamboo through bamboo rhizomes appeared most drastic in the middle stage of the rapid growth period, and five-year-old bamboo was the origin of nutrient transportation towards young bamboo with younger bamboo being the main source of nutrients throughout its rapid growth.
The anatomy, photosynthesis, as well as physiological and biochemical characteristics (including the cell membrane, osmotic regulation, and enzymatic antioxidant systems) of leaves were investigated in Rhododendron 'Zhuangyuan Hong' to study the effects of heat acclimation on the thermostability of Rhododendron. Plants were exposed to two heat stress levels (38℃ and 42℃) for 6 days, respectively, with a heat acclimation pretreatment at 30℃ for 6 days. Results for a high temperature treatment showed that compared to leaves without heat acclimation, leaves with heat acclimation had less damage on the anatomy. The ratio of palisade and spongy, tissue was increased significantly and RCT also was increased. Leaves with heat acclimation maintained a significantly higher net photosynthetic rate(Pn) and lower intercellular CO2 concentration(Ci), and had a lower content of hydrogen peroxide (H2O2) and malondialdehyde (MDA), which helped stabilize cell structure. Also, activity of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) were lower at 38℃ with POD and CAT activities being higher at 42℃. This study showed that heat acclimation could maintain a stable leaf structure, could improve the photosynthetic rate, and could reduce the extent of cell damage; hence, to some degree improving thermostability.
Salt stress is a major crisis for growth and development of fruit seedlings. To improve salt tolerance of Actinidia deliciosa (kiwifruit), wild A. deliciosa seedlings were used as material to determine the effect of exogenous melatonin (MEL) on physiological mechanisms. The experiment was conducted in 2016 and 2017 at Sichuan Agricultural University in Chengdu, Sichuan Province. Kiwifruit seedlings were irrigated with a MEL solution and treated with 100 mmol·L-1 NaCl stress. Kiwifruit leaves were sampled at foundation up to 3 to 5 euphyllas at 0, 3, 6, 9, 12 d after treatment. Protective enzyme activity[superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT)], ascorbic acid (AsA) content, and osmotic substances content were determined with treatments of a control (ck), NaCl stress (S1), and melatonin treated along with NaCl stress (S2). Results showed that compared to the control (ck), malondialdehyde (MDA) content, proline content, SOD activity, POD activity, and CAT activity of kiwifruit with NaCl stress significantly increased first and then decreased (P < 0.05). In addition, AsA content first decreased and then increased (P < 0.05). The content of hydrogen peroxide (H2O2) and soluble sugar significantly increasing (P < 0.05). For the degree of membrane lipid peroxidation, MDA concentration reduced 102.45% at 6 d and H2O2 concentration decreased 44.35% at 12 d in S2 compared to S1. At the same time, the seedlings with melatonin have the higher level of proline, soluble sugar, soluble protein, AsA content, and the antioxidant enzymes activity (SOD, POD, and CAT) than without melatonin (P < 0.05). Thus, exogenous melatonin could alleviate damage to kiwifruit seedlings and improve salt tolerance.
The J3 gene mediates the integration of flowering signals in Arabidopsis thaliana. To explore the functions of the J3 gene in bamboo plants, a J3 homolog named PvJ3 was isolated from Phyllostachys violascens, and a preliminary analysis of its function was conducted with Ph. violascens. Analyses included a sequencing alignment and phylogenetic analysis, real-time quantitative PCR, and protein subcellular localization. Results showed that the phenotype of overexpression of PvJ3 in Ph. violascens predated flowering and had more main stems. The full-length ORF of the PvJ3 in Ph. violascens was 1 260 bp which encoded 419 amino acids. The sequencing alignment and phylogenetic analysis of PvJ3 showed a high homology with other species. Real-time quantitative PCR results showed that the PvJ3 was expressed in all organs both in flowering and non-flowering bamboo plants and was highest in the stem of flowering bamboo plants. Protein subcellular localization showed that PvJ3 was located in the cytoplasm and cell nucleus. These results suggest that PvJ3 may promote flowering, may participate in stem development, and may provide a scientific basis for the regulation of bamboo flowering.
In this study, expressed sequence tags (ESTs) were identified by EST-simple sequence repeat (SSR) markers. The optimal amplification reaction system for EST-SSR was established by orthogonal design of an L16(45) orthogonal experiment, and it was established for orthogonal design of template DNA, Mg2+, dNTPs, and TaqDNA enzyme and primer. Then, Osmanthus fragrans transcriptase EST-SSR polymorphism primers were screened. Finally, the polymorphic primers and cluster analysis were used to identify the cultivars cultivated in Sichuan Province. Results showed that the EST-SSR optimal reaction system of O. fragrans contained 40 ng template DNA, 2.25 mmol·L-1 Mg2+, 0.3 μmol·L-1 primer, 0.3 mmol·L-1 dNTPs, TaqDNA polymerase 1.25×16.67 nkat, 10×PCR Buffer 2 μL, and ddH2O to 20 μL. A total of 19 SSR primers with high stability and high polymorphism were screened from 150 pairs of EST-SSR primers. The polymorphism was five nucleotides (25.00%), six nucleosides acid (19.44%), and trinucleotide (16.67%). Altogether a total of 14 samplings of O. fragrans cultivars cultivated in Chengdu, Sichuan Province were identified by high sensitivity polymorphic SSR primers. Analysis of genetic diversity, molecular breeding, and identification and protection of cultivars have laid a strong foundation for O. fragrans.
Selection of training samples, a direct factor affecting the accuracy of supervised classification, with a higher spatial resolution image, requires more accurate training samples, but the human-computer interaction capabilities in the selection of training samples is limited. Therefore, in this study, an algorithm was provided for automatic extraction of training samples. Airborne hyperspectral data and LiDAR data were used in Gutian Mountain National Nature Reserve. The hyperspectral data were used to extract training samples automatically and variables of tree species were calculated. According to differences in structure and height of individual trees provided by the canopy height model of LiDAR, a tree height mask was made to help circumvent the problem of different objects with the same spectra and identical objects with different spectra, as far as possible. Then, the spectral angle between each pixel and training sample pixel was calculated and highly pure pixels at different heights were selected automatically. In addition, a vegetation index and principal component analysis were calculated. The precise classification of tree species was carried out by a support vector machine classifier in the study area. The experiment used a method of stratified-auto sample selection to extract the training samples of broadleaf, Masson pine, Moso bamboo, Chinese fir, and tea-oil tree forests, and then classified these five tree species. Results showed that the combination of hyperspectral data, LiDAR data, and the structure of the insensitive pigment index revealed an overall accuracy of 89.12% and a Kappa coefficient of 0.86. Using a combination of the best variables, the user accuracy was as follows:broadleaf forest--75.00%, Masson pine--100.00%, Moso bamboo--86.36%, Chinese fir--90.91%, and tea-oil tree--96.55%. Therefore, integration of different remote sensing data, stratified-auto sample selection, and hyperspectral variable selection using LiDAR and the structure insensitive pigment index were effective ways for improving tree species classification.
The aim is to summarize the growth process for first generation Mongolian pine (Pinus sylvestris var.mongolica) on sandy land, where its life cycle ends after about 60 years, and to provide a theoretical basis for promotion, regeneration, and management of a Mongolian pine plantation. 11 trees were selected for analysis, chosen from standard plots of 11 Mongolian pine plantation stands (> 30 a) with different site conditions in Zhanggutai of Liaoning Province. Then parameters for Richards model were solved and the goodness-of-fit was tested. To reveal the growth process of Mongolian pine, eigenvalues of Mongolian pine trees were used in Richards Equation. Results of height, diameter at breast height (DBH), and volume of Mongolian pine were simulated by Richards model with the parameter estimated values of 14.179, 0.084, and 2.803 for height; 19.379, 0.075, and 1.712 for DBH; and 0.296, 0.062, and 5.926 for volume. For tree height growth of first generation Mongolian pine introduced to Zhanggutai, the relative growth rate reached its maximum of 0.54 m·a-1 at year 12.3, and the average growth rate achieved its peak at year 21.4 with 0.39 m·a-1. Growth of DBH for trees started at year 6.6 with the relative growth rate reaching its maximum of 0.77 cm·a-1 at year 14.0 and the average growth rate achieving its peak at year 26.0 with 0.47 cm·a-1. Volume growth was very slow before age 12.0 with the relative growth rate reaching its maximum of 0.007 4 m3·a-1 at 29.0 years, the average growth rate achieving its peak at year 47.0 with 0.004 5 m3·a-1. The quantitative maturity age, when the maximum of average growth rate of volume appears, was 47.0 years of Mongolian pine in Zhanggutai. We drew a conclusion that the maximum of relative growth rate of height, DBH and volume of Mongolian pine appear at the age of 12.3 a, 14.0 a and 29.0 a, respectively. The maximum of average growth rate of height, DBH and volume appear at the age of 21.4, 26.0 and 47.0 years, respectively. The quantitative maturity appears in the 47th year after planting.
For rational forestry use of barren hills in a semi-arid area, site classification and a vegetation suitability evaluation were conducted for afforestation on hilly land in July and August 2016 in Xinghe, Inner Mongolia. Three soil profiles were set to investigate soil moisture, physical and chemical properties in each plot, also the average height of young Pinus tabulaeformis and average aboveground biomass of three herbaceous quadrat were investigated in 38 plots with the size 10 m×20 m. Results concerning relationship between vegetation growth and site conditions showed that the main factors significantly affecting P. tabulaeformis included soil thickness and average soil moisture content (P < 0.05); whereas, those significantly affecting herbaceous biomass included surface soil moisture content, surface total nitrogen content, surface total phosphorus content, and gravel content (P < 0.05). Based on the single factor analysis, topography, landform, slope aspect, soil texture, soil thickness, and gravel content could make effect on soil moisture or total phosphorus content (P < 0.05), and therefore these were selected as factors for site classification type with eight site types defined for afforestation in hilly land. In vegetation suitability evaluation, eight site types were divided into four ranks based on their vegetation growth. Sites in the 1st class were both suitable for P. tabulaeformis saplings and herbaceous plants. Sites in the 2nd class were suitable for P. tabulaeformis but not for herbaceous plants. Sites in the 3rd class were suitable for herbaceous plants, while P. tabulaeformis had a normal growth. Sites in the 4th class were not suitable for P. tabulaeformis, although the herbaceous plants grew well. In order to take full advantage of barren hills, sites in 1st and 2nd class were suggested to be forest land. Sites in the 3rd class could be planned as mixed forest of arbor and shrub, and sites in 4th class could be planned as grassland.
The research is aimed to expand the scope of urban trees protection, promote urban residents' more rational understanding and appreciation of trees, and encourage their active participation in and promotion of urban forest construction. Selecting the main city area of Hefei as the research site, the research tried to identify the notable trees. The evaluations of index system and identification methods were established:historical witness and social culture were selected as the qualitative indicators; tree age and vitality, tree weight, tree species, site location, and aesthetic value were selected as 5 first-level quantitative indicators, and tree height, DBH, crown width, color and etc. were selected as 12 secondary quantitative indicators. The notable trees can be defined as the urban trees with rich historical and cultural connotations and aesthetic value, or with the features such as large size, beautiful shape, important or eye-catching position, rare species, public concern and popularity. Totally 112 trees were identified as notable trees in the main urban area of Hefei City, belonging to 23 species, 23 genera and 18 families. The number was five times more than the registered ancient and famous trees, which could be considered an effective complement to the ancient and famous trees. Among the identified notable trees, there were some differences in the characteristics such as tree species distribution, tree age structure, DBH distribution, spatial distribution, evergreen deciduous ratio and so on. It provided a new idea and suggestion on maintaining urban ecological balance and biodiversity, expanding the protection and research of the individual resources of the trees in the city.
This experiment was conducted to invesigate the effects of different food components on the physiological and biochemical indexes and digestive tract of small birds (Passer montanus), for understanding the survival strategy of P. montanus through self-regulation in response to adverse changes in environmental conditions. The birds were randomly divided into three groups:a control group (fed with millet-Setaria italica), a grass seed group (fed with grass-Echinochloa crusgalli seed), and a mealworm group (fed with mealworms-Tenebrio molitor). The birds have been domesticating for four weeks until the relevant indicators were detected, such as the basal metabolic rate (BMR) and body mass, organ quality of fresh and dry weight, body fat mass fraction, glycogen content, length of the digestive tract and the digestive tract mucous membrane layer thickness and height, width, cross-section of the intestinal wall. Results showed that the basal metabolic rates of the birds in the three groups (control group, grass seed group, mealworm group) were increased by 0.14, 0.35 and 0.11 mL·g-1·h-1 respectively compared with the first week, and it was higher in the grass seed group than those in the other two groups (P < 0.05). Body mass of the birds were all extremely significantly different between groups (P < 0.01). Organ fresh weight of the large intestine, small intestine, duodenum and rectum were extremely significantly higher in the grass seed group than those in the grass seed group and control group (P < 0.01). Dry weight of duodenum and muscle stomach of the birds in the mealworm group were extremely significantly higher than those in the grass group and control group (P < 0.01), while dry weight of the colon and rectum in control group were extremely significantly higher than those in the grass group and mealworm group (P < 0.01). Digestible energy and digestibility of the birds in the mealworm group was significantly higher than those in the grass group (P < 0.01). The length of large intestine, small intestine, duodenum of the birds were extremely significant difference among the three groups (P < 0.01). The heights of large intestinal villus in the grass seed group and mealworm group were extremely significantly different with those in the control group (P < 0.01), and the height and mucosal layer thickness of small intestine and duodenum villus in the control group and grass seed group were all extremely significantly different with those in the mealworm group (P < 0.01). The differences of food component is one of the important environmental factors that would influence energy metabolism and digestive tract morphological structure of P. montanus.
To reduce the light-induced discoloration of printed veneer, nano-TiO2 and nano-ZnO were chosen to modify red UV ink and yellow UV ink. Relative ink quality of 0.5%, 1.0%, 1.5% and 2.0% of modifier was added to UV ink by stirring. Then the modified UV ink was printed on the surface of poplar veneer. Using a laser particle sizer, UV-Vis spectrophotometer, and colorimeter, physical properties of the modified ink and color differences printed on poplar veneer were studied. Results showed that the average particle size of the UV inks modified by nano-TiO2 decreased a little while the UV inks modified by nano-ZnO had no change. Absorbance of UV ink in the ultraviolet region was increased with the addition of nano-TiO2 or nano-ZnO. Both of nano-TiO2 and nano-ZnO could prevent light-induced discoloration of printed veneer. But when UV ink modified by nano-ZnO was printed on a veneer surface, the color difference was lower than those modified by nano-TiO2. The optimum amount of nano-ZnO in red UV ink was 1.5%, and the ΔE* of the printed veneer was 0.41. Compared with the veneer printed by unmodified red UV ink, ΔE* decreased 78.1%. The optimum amount in yellow UV ink was 0.5%, and the ΔE* of the printed veneer was 3.12. Compared with veneer printed by unmodified yellow UV ink, ΔE* decreased 66.9%.
To improve the situation that there is few special equipment for biological pesticide spraying, the air assisted centrifugal atomization device has been designed and manufactured. By changing the structural parameters (diameter, number of teeth, bevel) and operating parameters (flow rate, rotational speed and wind speed), this research conducted experiments on the particle diameter, biological pesticide activity and efficacy trials. The main findings are as follows:The bigger atomization wheel diameter is the smaller atomized particle size will be; the smaller the angle degree is the greater atomized particle size will be; the larger number of teeth is the smaller atomized particle diameter will be. As a result, the best combinations of disc nozzle structural parameters have been recommended for various environments. Another conclusion is that the wheel diameter, the turntable angle, and number of teeth have little influence on biological pesticide activity, thus meeting the requirement of plant pest prevention and control. The optimal combination of operational parameters are as follows:The flow rate is 40 L·h-1; the speed is 6 000 r·min-1 and the wind speed is 5 m·s-1. From the perspective of pesticide efficacy, Plutella xylostella mortality rate is over 90%, which meets the use requirements.
Salvia miltiorrhiza, a traditional Chinese herbal medicine, is widely used in preventing and treating cardiovascular diseases. Due to the increasing demand of raw materials of S. miltiorrhiza, its quality has attracted more and more attentions. Tanshinone is one of the main pharmacodynamical components. How to make innovations to improve the content of effective pharmacodynamical component and improve the quality of S. miltiorrhiza based on the existing research is an important work for the researchers. In this study, the latest research progresses on the cloning and identification of genes and transcription factors involved in the biosynthesis pathway of tanshinones, the molecular mechanism of how the elicitors to improve the biosynthesis of tanshinones were reviewed. And then the problems of existing research and the future research direction involved in our recent research were also sorted out and discussed. In order to get a comprehensive knowledge about the molecular mechanism on the production of tanshinones, researchers should pay more attention to three key items. Firstly, alternative splicing of key regulatory factors underlying the biosynthesis of tanshinones should be discovered and identified. Secondly, regulation of the biosynthesis of tanshinones medidated by non-coding RNA shoud be paid more attention. Finally, we should pay more efforts to realize the fact of production of tanshinones using the stratagies of synthetic biology.
Deconvolution beamforming as a noise source identification method based on beamforming has been widely used, especially in the identification of forestry machine noise. Compared with the conventional beamforming, deconvolution beamforming method is more effective to reduce the width of the main lobe and eliminate the side lobe, and improve the spatial resolution. This paper reviewed the recent research progress on deconvolution beamforming at home and abroad. A comparative analysis was made among several representative methods on the aspects of the side lobe suppression ability, positioning accuracy and computational efficiency. Then the characteristics and limitations of those typical deconvolution beamforming algorithms were discussed, which provided a new research idea for future improvement in order to obtain a more comprehensive deconvolution beamforming algorithm with better applicability.
Distylium buxifolium is an important native ornamental tree species used extensively in gardens. To choose the right D. buxifolium clones suitable for different soil conditions and to provide references for early promotion and application, this study used potted plants in a greenhouse with red soil, yellow soil, calcareous (lime) soil, and coastal solonchak soil. Four clones D1, D7, D13, D19 of annual nursery stock were used to determine seedling height, ground diameter, crown width, and new tips, and then the influence of different soils on seedling growth was studied. Results showed that seedling height, ground diameter, and crown breadth in red soil were significantly greater(P < 0.05) than the other three soil types, while the number of new tips in coastal solonchak soil being the largest (P < 0.05). Seedling height of clone D19 reached 5.7 cm, which was significantly higher than clone D7(P < 0.05), ground diameter and crown breadth of clone D7 reached 0.74 cm and 9.88 cm, which were significantly higher than other clones (P < 0.05), and the number of new tips of clone D13 reached 56.40, which was significantly greater than the other clones (P < 0.05). Suitability of soils for D. buxifolium clones was red soil > yellow soil > calcareous soil > coastal solonchak soil. Also, favorable growth of clones was in the order D7 > D13 > D1 > D19. Clone choices of D. buxifolium for soil types could be D1 or D19 for yellow soil, D7 or D13 or D19 for red soil, D7 or D13 for lime soil, and D1 or D7 for coastal solonchak soil.