2017 Vol. 34, No. 5

A comparative study of dimension reduction methods for airborne hyperspectral images
FENG Yunyun, LIU Lijuan, LU Dengsheng, PANG Yong
2017, 34(5): 765-774. doi: 10.11833/j.issn.2095-0756.2017.05.001
[Abstract](2592) [HTML] (616) [PDF](655)
Abstract:
Hyperspectral datasets have been widely used in monitoring analyses of vegetation due to their abundant spectral information; however, their spectral resolution greatly increases information redundancy causing more data processing work. To find an efficient method for selecting the most representative bands to reduce redundancy before using them, three traditional dimension reduction methods, namely Wilks' Lambda (WL), random forest (RF), and adaptive band selection (ABS), were used to select optimal bands among the 64 bands. Then, a new evaluation method based on a curve error index was proposed to determine the appropriate number of bands through analysis trend of the index values and to select the best dimension reduction method. Lastly, classification results were used to demonstrate the validity of this method. Results indicated that WL selected 10 bands and the α6-αsmooth value (the curve error difference between selecting six bands and when the curve becomes stable) was 0.05. The RF method selected 13 bands and its corresponding α6-αsmooth value was 0.06. The ABS method selected 20 bands and its α6-αsmooth value was 0.14. The overall accuracy of WL based band selection was 80.56% with a Kappa coefficient of 0.77; RF was 79.11% with a Kappa coefficient of 0.76; and ABS had an overall accuracy of 49.94% and a Kappa coefficient of 0.41. Thus, (1) with the curve error index method WL presented the smallest α6-αsmooth value and had the highest overall classification accuracy, suggesting WL was the optimal method for dimensional reduction, and (2) the two evaluation methods had the same results, illustrating the curve was feasible.
Comparison of fitting approaches with biomass expansion factor equations
HUANG Xingzhao, WANG Zefu, XU Xiaoniu
2017, 34(5): 775-781. doi: 10.11833/j.issn.2095-0756.2017.05.002
[Abstract](3006) [HTML] (585) [PDF](397)
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Biomass equations for the biomass expansion factor (fBEF) have been widely applied for accurate stand biomass estimations. The question here is how to improve the fitting precision of these biomass expansion factor (fBEF) equations by using different methodologies. Stand biomass data were obtained from 53 permanent sample plots located in Cunninghamia lanceolata plantations of Anhui and Fujian Provinces across China. The least squares approach, the nonlinear mixed model approach, and the hierarchical Bayesian approach were applied to establish BEF equations so as to test the effect of regions. Split-plot design with regions of Anhui and Fujian Provence and sample plots as replications. Results showed significant differences between Fujian and Anhui Provinces for stand biomass, volume, and fBEF at different ages. The R2 and mean deviation (dMD) values for the least squares approach was R2 = 0.643, dMD = 0.376; for the nonlinear mixed model approach was R2 = 0.802, dMD = 0.233; and for the hierarchical Bayesian approach was R2 = 0.804, dMD = 0.228. Also, there were highly significant differences in fitted results between the least squares and the nonlinear mixed model approaches, as well as between the least squares and the hierarchical Bayesian approaches (P < 0.01). However, no significant differences were found between the nonlinear mixed model approach and the hierarchical Bayesian approach (P = 0.547). Thus, both the mixed model approach and the Bayesian hierarchical approach were effective methods for estimating stand biomass at the regional scale.
Based on mixed-effects model and empirical best linear unbiased predictor predicting growth profile of height for Chinese fir
WANG Mingchu, SUN Yujun
2017, 34(5): 782-790. doi: 10.11833/j.issn.2095-0756.2017.05.003
[Abstract](3021) [HTML] (586) [PDF](372)
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Based on the data of 30 sample trees from 15 permanent plots of Chinese fir in the national forest farm of Jiangle, at first we study the best function as the base model with the least square method among five growth profile equations. The nonlinear mixed model was constructed based on the base model and modeling data. We use the R for model fitting. Select the mixed model with the minimum value of AIC, BIC and the maximum value of Loglik as the best model by changing the number of mixed parameters in fitting progress. Using mixed model to predict growth profile of height and studying the characteristics of Empirical Best Linear Unbiased Predictor (EBLUP). Fitting results showed the simulation's precision of Weibull's including three random effect parameters(β1, β2 and β3) was maximal. In the analysis of prediction, prediction accuracy decreased as age interval of observations extended with the same number of previous observations. MSE decreased as the number of previous observations increased. EBLUP prediction could fully predict individual growth process, given that there were multiple previous observations with long-enough age intervals.
Classification of forestry images based on the BoW Model
ZHANG Guangqun, LI Yingjie, WANG Hangjun
2017, 34(5): 791-797. doi: 10.11833/j.issn.2095-0756.2017.05.004
[Abstract](2228) [HTML] (354) [PDF](362)
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For characteristics of forestry images, an image classification method was put forward based on Dense SIFT and the BoW Model with support vector machine (SVM) using a histogram intersection kernel in order to improving to meet the need of the forest resources management. First, using the BoW Model, the Dense SIFT features of forestry images were extracted to describe the image. Then SVM was used for classification to identify the category of the images. Different kinds of kernel functions like Poly, RBF, Sigmoid, and the histogram intersection kernel were used to find the best recognition rate. Experimental results showed that using Dense SIFT had a shorter detection time (t=60.143 s) and a higher recognition rate (r=86.7%) than SIFT (t=95.567 s and r=83.3% respectively), and it was suited for high real-time applications. Also the histogram intersection kernel had a higher average recognition (r=86.7%). Combining Dense SIFT and the BoW Model with SVM and using the histogram intersection kernel, algorithms used with three kinds of forestry images had a better average recognition (r=86.7%).
Effects of grazing on microbial biomass C, N and respiration in Artemisia frigida rhizosphere soil
WANG Xinzhao, HAN Yilin, LI Mei, WANG Xiaodong, WANG Junyu, MA Yuandan, Baoyintaogetao, GAO Yan, ZHANG Rumin
2017, 34(5): 798-807. doi: 10.11833/j.issn.2095-0756.2017.05.005
[Abstract](4322) [HTML] (468) [PDF](393)
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Artemisia frigida is a common plant, especially in degraded grasslands, on the Inner Mongolian steppes. To reveal the effects of grazing disturbance on soil microorganisms of the A. frigida rhizosphere, soil microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), and basal respiration and correlation were discussed, by the chloroform fumigation extraction method and the LI-7000 CO2/H2O system. Rhizosphere soil of A. frigida (ARS) and non-rhizosphere soil (NRS) under three grazing intensities, no grazing (CK) plot, light grazing (LG) plot, heavy grazing (HG) plot, were chosen as experimental sites in the Inner Mongolian steppes. Results showed that compared with the control group, the soil microbial biomass carbon, nitrogen and basal respiration after light grazing treatment increased by 22.7%, 45.0%, 17.2%, respectively. These bio-indicators in A. frigida rhizosphere soil were higher than non-rhizosphere soil of A. frigida (P < 0.05). Also, the increasing rate of MBN in rhizosphere and non-rhizosphere soil was higher than that of MBC. In the rhizosphere soil of Artemisia frigida, MBC had a positive correlation with organic matter (r = 0.737), total N (r = 0.798), available N (r = 0.945), and total K (r = 0.697). The MBN had a positive correlation with organic matter (r = 0.906), total N (r = 0.915), available N (r = 0.937), and total K (r = 0.691).The basal respiration had a positive correlation with organic matter (r = 0.507), total N (r = 0.446), available N (r = 0.805), and total K (r = 0.898). The light grazing treatment can contribute to a increase to microbial biomass and basal respiration rate. This study provided a theoretical basis for further exploring of ways that A. frigida could help resist grassland degradation.
Comparing water-holding capacity in forest litter and soils for an aerially seeded Pinus massoniana plantation with different stand densities
CHU Xin, PAN Ping, GUO Liling, NING Jinkui, OUYANG Xunzhi, WU Zirong
2017, 34(5): 808-815. doi: 10.11833/j.issn.2095-0756.2017.05.006
[Abstract](2410) [HTML] (567) [PDF](374)
Abstract:
In order to provide guidelines for making effective measures to improve water-holding capacity for an aerially seeded Pinus massoniana plantation, this research was conducted to compare water-holding capacity of forest litter and soils with method of one-way ANOVA test in different stand densities. Four groups [Group Ⅰ(900-1 500 culm·hm-2), Group Ⅱ(1 500-2 100 culm·hm-2), Group Ⅲ(2 100-2 700 culm·hm-2), and Group Ⅳ(2 700-3 300 culm·hm-2)], were set up according to aerially-seeded Pinus massoniana forest density. Sample-plot surveys and sample determination were carried out for a fixed 20 m × 20 m standard plot which selected with three replications in each group. Results showed that, (1) the litter storage capacity for each density group in the half-decomposed litter layer was higher than the undecomposed layer. Total storage capacity for litter, maximum water-holding capacity, and effective water-holding capacity of the Group Ⅱ were the largest, respectively up to 4.26 t·hm-2, 11.55 t·hm-2, 9.79 t·hm-2, and were in the order of density Group Ⅱ > Group Ⅲ > Group Ⅰ > Group Ⅳ compared with other groups. The maximum water-holding capacity and effective water-holding capacity of density Group Ⅱ were significantly higher than those of the other density groups (P < 0.05); however, the total storage capacity of litter in each density group was not significantly different (P > 0.05). (2) The non-capillary water-holding capacity, capillary water-holding capacity, and maximum water-holding capacity of soil in the four groups showed no significant differences between density groups (P > 0.05). In conclusion, by controlling stand density of an aerially seeded Pinus massoniana plantation at 1 500-2 100culm·hm-2, the water-holding capacity of the litter and soil would be maximized.
Variation characteristics of an invasive Alternanthera philoxeroides community along latitudinal gradients in spring
WU Hao
2017, 34(5): 816-824. doi: 10.11833/j.issn.2095-0756.2017.05.007
[Abstract](2116) [HTML] (434) [PDF](338)
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Latitude and season are the crucial environmental factors that affect biological invasions, such as Alternanthera philoxeroides, a malignant invasive weed native to South America and now widely found in several provinces of China. To explore variation characteristics of an A. philoxeroides community along latitudinal gradients and also to test its invasive effect on native plant diversity (α diversity indices) and community stability (Godron coordinate values) in spring, a latitudinal field survey was conducted in April with 15 invasive and 15 control plots selected in the 22°-30° N (spanning Guangdong, Guangxi, Hunan, and Hubei Provinces) terrestrial habitats of South China. Analysis included the ordination method of canonical correspondence analysis (CCA) based on species and environmental matrixes, as well as the curve regression between A. philoxeroides cover and α diversity indices (the Simpson, Shannon, Pielou, and Patrick indices). Results showed that: 1) species cover of Alternanthera philoxeroides increased with increasing latitude from 22°-30° N of China with the Simpson, Shannon, and Pielou indices all significantly and negatively correlated (P=0.012, r=-0.629; P=0.020, r=-0.591; P=0.024, r=-0.579, respectively) to latitude in the invasive community but significantly and positively correlated (P=0.041, r=0.533; P=0.020, r=0.591; P=0.010, r=0.641, respectively) in the control community. The Patrick index had no significant correlation with latitude. 2) Invasion decreased species diversity at the whole community level (t=7.811, P < 0.001). However, a slight invasion (A. philoxeroides cover < 25%) improved diversity, and with invasion cover increasing, species diversity indices were unimodal. In spring the Godron values between invasive and control communities were similar. 3) Invasive plots recorded 45 plant species; whereas, control plots recorded 125 plant species. Plant species of these two community types formed three separate distribution areas in the CCA two-dimensional diagrams with the invasive community having a higher distribution density. A. philoxeroides was near to the central position indicating it had a wider latitudinal adaptability. These findings would be helpful for predicting dynamics of an invasive plant community and also very important for biological invasion control and native biodiversity protection.
Undergrowth diversity at different ages of Juglans mandshurica forests in the Songshan National Nature Reserve, Beijing
ZHENG Changlong, WANG Jianming, LI Jingwen
2017, 34(5): 825-832. doi: 10.11833/j.issn.2095-0756.2017.05.008
[Abstract](2476) [HTML] (512) [PDF](328)
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To effectively protect the Juglans mandshurica forest and prevent it's further habitat deterioration in Beijing, the study attempted to clarify the distribution characteristics of the undergrowth plant diversity. Shrub and herb plant species composition and diversity were researched at different forest ages of Juglans mandshurica forest in the Songshan National Nature Reserve by the typical sampling method that twenty-four 20 m×20 m plots were set up in different typical stands, and one 5 m×5 m shrub sample and one 1 m×1 m herb sample were made at each quadrangle and center of each arbor sample. Diversity analysis included richness index (M), Shannon-Wiener diversity index (H), and Simpson diversity index (D). Results showed that as forestsincreased in age, shrub species and quantities increased, and herb species and quantities decreased. The most important herb plant species in the young and middle-aged forests were Carex lancifolia, Spodiopogon sibiricus, Aconitum carmichaelii, and Agrimonia pilosa; whereas, in the nearly mature forests and mature forests Rabdosia japonica and Chelidonium majus were predominant. Shrubs were dominated in the young forests and middle-age forests by Rhamnus parvifolia and Vitex negundo var. heterophylla but in the nearly mature forests and mature forests by Caragana rosea, Deutzia parviflora, Syringa pubescens, and Syringa reticulata var. mandshurica. There were significant differences in species diversity indices between shrub layer and herb layer in Juglans mandshurica forest at different ages(P < 0.05). In the shrub layer, with the increase of age, Simpson index increased from 0.598 0 to 0.787 9, the Shannon-Wiener index is 1.183 9 to 1.835 6, the Pielou evenness index is 0.682 0 to 0.839 0, and the Margalef richness index is 0.979 0 to 1.614 9, showing a continuous increase trend; In the herb layer, the Pielou evenness index increased from 0.884 6 to 0.987 2, and the Simpson index decreased from 0.843 6 to 0.759 4, and the Shannon-Wiener index decreased from is 2.120 9 to 1.673 9, while the Margalef richness index is 1.951 7 to 1.347 1, and decreased with the increase of stand age. Shrub layer and herb layer of Juglans mandshurica forest under different forest ages was significantly different(P < 0.001). The species richness of shrub layer increased from 3.385 7 to 6.340 0 from young forest to mature forest, and reached the highest value in mature forest stage. The change of herb layer was opposite to that of shrub layer. With the increase of age, the species of the herb layer in the undergrowth layer decreased gradually. Using the semi-variogram model, Pielou evenness index and Simpson index were spherical model, Shannon-Wiener index and Margalef richness index were more consistent with it. The species diversity of the study area was moderate spatial correlation, the proportion of structural factors is 0.584-0.681, and the proportion of random factors is 0.319-0.416. For spatial variation of species diversity, human factors were dominant. Therefore, reasonable planning and development activities at the local level should be undertaken with local residents conducting seed collection and other management activities.
Coupling research on functional regionalization and ecological vulnerability in the Jinsiwan Forest Park
ZENG Qi, LIU Jian, YU Kunyong, ZHANG Jinzhao, ZHENG Wenying, CHEN Zhanghao
2017, 34(5): 833-840. doi: 10.11833/j.issn.2095-0756.2017.05.009
[Abstract](2202) [HTML] (510) [PDF](499)
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For reasonable land-use planning and effective utilization of systems to reveal ecological vulnerability of different functional zones, functional requirements of the Jinsiwan Forest Park in Sanming City, Fujian Province, the study area, were analyzed and categorized. Spatial distribution of environmental vulnerability was analyzed by choosing slope, vegetation coverage, and the potential human disturbance factor to establish an evaluation system of ecological vulnerability for a comprehensive evaluation. Moreover, the relationship between functional utilization and ecological vulnerability was analyzed by applying a coupling degree model. Results showed that the study area was divided into four functional ecological zones including: water conservation (631.01 hm2 or 37.1%), soil and water conservation (844.91 hm2 or 49.7%), an overlapping area of water conservation with soil and water conservation (219.90 hm2 or 12.9%), and landscape and recreation (4.91 hm2 or0.3%). Ecological vulnerability in the study area was mainly in Zone Ⅱ (0.2 < IEV ≤ 0.4) and Zone Ⅲ (0.4 < IEV ≤ 0.6). The areas of low vulnerability were mainly distributed in the central parts of the study region; whereas, areas of high vulnerability were located around the edges. The vulnerability of different functional areas differed with landscape and recreation mainly belonging to Zone Ⅳ (0.6 < IEV ≤ 0.8), soil and water conservation as well as the overlapping area of water conservation with soil and water conservation belonging to Zone Ⅲ, and water conservation belonging to Zone Ⅱ. There was almost a high coupling between each function and the corresponding vulnerability zone. Thus, there was a close relationship. The study has a guidance for the optimization of land use in the Jinsiwan Forest Park and maintaining ecological health and stability.
Growth response of a Cunninghamia lanceolata plantation to thinning in southwestern Guangxi, China
ZENG Ji, LEI Yuancai, CAI Daoxiong, TANG Jixin, MING Angang
2017, 34(5): 841-848. doi: 10.11833/j.issn.2095-0756.2017.05.010
[Abstract](2147) [HTML] (406) [PDF](293)
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To reveal the dynamic response of stand growth to thinning treatments and to select suitable thinning intensities in Cunninghamia lanceolata (Chinese fir) plantations, a thinning trial was conducted in a 14-year-old plantation of C. lanceolata at Pingxiang City, Guangxi. Stand density was about 1 219 trees·hm-2, and the experiment was arranged in a randomized complete block design with five treatments: four thinning treatments of 69% (Ⅰ), 60% (Ⅱ), 51% (Ⅲ), and 40% (Ⅳ) and a control without thinning and four replicates for each treatment. Diameter at breast height (DBH), tree height, crown base height (CBH), crown width (CW), individual tree volume (ITV), and stand volume (SV) were determined with a circle samping plot of 400 m2 for each replicateperiodically in 9 years after thinning. Results from one-way analysis of variance and Duncan's multiple range tests showed that thinning intensity significantly increased DBH and ITV, decreased CBH and SV (P < 0.05). The highest DBH and ITV were observed in Treatment Ⅲ; whereas, the highest CBH and SV were in the control. The mean annual increments for DBH, CW, and CBH were highest 1 to 3 years after thinning with differences between treatments gradually declining as forest age increased; however, peaks for tree height, ITV, and SV growth occurred 3 to 5 years after thinning. Based on the above findings, a thinning intensity of about 50% (Treatment Ⅲ) should be applied for close-to-natural forest management so as to producelarge-sized timber of C. lanceolata more rapidly.
Logging age for the Bambusa rigida culm based on physical-mechanical properties
LI Feng, QI Jinqiu, XIAO Hui, CHEN Yuzhu, XIE Jiulong, HUANG Xingyan
2017, 34(5): 849-855. doi: 10.11833/j.issn.2095-0756.2017.05.011
[Abstract](2465) [HTML] (557) [PDF](256)
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To optimize the logging age of the Bambusa rigida culm, physical-mechanical properties of bamboo culms aged from 0.5 to 4.5 years were sampled by age with sample size of 10 for each age bamboo culm and evaluated according to national standards from Testing Methods for Physical and Mechanical Properties of Bamboos (GB/T 15780-1995) and the radial bending test method. Data from different bamboo ages were statistically analyzed with ANOVA. Results showed that (1) the moisture content of green bamboo and volumetric shrinkage decreased with an increase in bamboo age from 0.5 to 4.5 years; whereas, the basic density increased overall. Also, (2) compression strength parallel to the grain, modulus of rupture (MOR), and modulus of elasticity (MOE) reached a maximum at 3.5 years of age, and shear strength parallel to the grain had already leveled off at this age. (3) From the base to the top portion of the bamboo culm, moisture content of the green bamboo and volumetric shrinkage decreased; whereas, the basic density, compression strength parallel to the grain, shear strength parallel to the grain, MOR, and MOE all increased. Noteworthy was that shear strength, MOR, and MOE decreased at the top portion of the bamboo at age 4.5, which reflected the aging phenomenon of bamboo culms. (4) The 3.5-year-old bamboo culms had a moisture content of green bamboo, 60.67%; basic density, 0.72 g·cm-3; volume shrinkage, 12.54%; compression strength parallel to the grain, 82.41 MPa; shear strength parallel to the grain, 11.99 MPa; MOR, 237.13 MPa; and MOE, 18.32 GPa. Comprehensively, a matured 3.5-year-old Bambusa rigida culm was recommended as the optimal logging age.
Cloning and expression analysis of the PmGPX gene encoding glutathione peroxidase in Pinus massoniana
CHEN Hu, JIA Jie, LUO Qunfeng, WU Dongshan, YANG Zhangqi
2017, 34(5): 856-863. doi: 10.11833/j.issn.2095-0756.2017.05.012
[Abstract](2578) [HTML] (576) [PDF](305)
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The study PmGPX genes was played a role in Pinus massoniana insect resistance, that the great significance for in-depth insect-resistant resistance mechanism in Pinus massoniana. PmGPX, a cDNA region encoding glutathione peroxidase, was cloned in the transcriptome sequencing analysis of one insect-resistant material in Pinus massoniana. Analyses included an amino acid sequence and an expression (qRT-PCR) analysis. Results showed that the total length of open reading frame (ORF) was 741 bp encoding 246 amino acids. The amino acid sequence analysis showed three high conservative character fields of the GPX gene family for this gene. The isoelectric point of PmGPX was PI 8.29, and the protein molecular weight was 27.08 kDa. In genetic clustering, compared with some other plants, PmGPX showed a higher homology with Picea sitchensis (91%) but a low homology with other monocots and dicotyledonous plants (64%-80%). However, homologies of the three typical conservative GPX family domains (G1, G2, G3) reached a higher level with other plants (82%-100%). The expression analysis indicated that PmGPX was expressed in all kinds of tissues with higher expression levels in leaves (P < 0.01), especially in young leaves (33.45 times more than the expression level in roots). Daily expression patterns were same in different insect-resistant materials and showed up-down-up-regulated trend the day. In insect-resistant material, expression of PmGPX reached a higher point earlier than that of control (P < 0.05 in old leaves and tender stem). The expression analysis also indicated that PmGPX was involved in the insect-resistant defense system of P. massoniana. This study laid a foundation for further analysis of the PmGPX biological function and its role in insect-resistant defense with Pinus massoniana.
Cloning and analysis of the CHS gene from a tissue culture of a red mutant strain in Vaccinium ashei
LIU Yanyan, ZHU Fangming, LIU Xiaozhen, ZHANG Hanyao
2017, 34(5): 864-870. doi: 10.11833/j.issn.2095-0756.2017.05.013
[Abstract](2063) [HTML] (387) [PDF](298)
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Blueberries (Vaccinium spp.) have attracted much attention because of their abundant anthocyanins; however, there have been few studies on the genes related to anthocyanin biosynthesis in blueberries. To analyze related genes of anthocyanin biosynthesis in blueberries and also to provide some bioinformatics basis for breeding of plants with a high anthocyanin content, a red mutant Vaccinium ashei was selected as the experimental material, and the full-length cDNA of chalcone synthase gene (CHS) was cloned by the homologous cloning method. The bioinformatics analysis showed that the full-length cDNA was 1 398 bp and had an open-reading frame (ORF) which was 1 170 bp encoding 389 amino acids. The homology on the nucleotide level of the CHS gene with the CHS genes of several species were 90% for Rhododendron simsii; 83% for Camellia japonica, Camellia chekiangoleosa, Actinidia chinensis, and Vaccinium corymbosum; and 82% for Malus domestica. The CHS protein of Vaccinium ashei had no signal peptide and no transmembrane domain. It was located in the cytoplasm, the peptide chain was hydrophobic, the α-helix and random coil were the largest constructional elements in the protein secondary structure, and β-turns and β-sheets were interspersed throughout the protein. The domain prediction of the encoded protein showed that the protein contained the chalcone synthase superfamily (CHS-like superfamily) domain. Thus inferred that the CHS gene of rabbit-eye blueberry was highly conserved, the expressed protein was hydrophobic, and it was a kind of protein with a relatively stable structure and properties.
hotosynthetic characteristics in different canopy positions of an Erythrophleum fordii plantation
HAO Jian, PAN Liqin, PAN Qilong, LI Zhongguo, YANG Guifang
2017, 34(5): 871-877. doi: 10.11833/j.issn.2095-0756.2017.05.014
[Abstract](1985) [HTML] (325) [PDF](273)
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To evaluate the photosynthetic characteristics of different canopy positions and to provide a photosynthetic physiological basis for pruning in an Erythrophleum fordii plantation, light intensity, light response curve, CO2 response curve, and the dynamic changes of photosynthetic factors were measured in different canopy positions of an E. fordii × Pinus massoniana plantation. Also, photosynthetic capacity of branches in different canopy positions was analyzed and a path analysis was conducted. Results showed that the different canopy positions significantly affected on initial slope photo inhibition (P < 0.05) and maximum net photosynthetic rate (P < 0.01), and ranked as canopy C > canopy B > canopy A; however, dark respiration rate was opposite. There was significant difference in the saturation light and light compensation point in differentcanopy positions (P < 0.01), the saturation light of higher canopy was greater, but the light compensation point was lower. Initial carboxylation efficiency and photosynthetic capacity higher in the canopy were greater than lower in the canopy with highly significant difference (P < 0.01), and the carbon dioxide compensation point of different positions in the canopy was in the reverse order. The relationship between photorespiration and photosynthesis was parallel. Daytime change of photosynthetic active radiation, transpiration rate, and leaf temperature in the three canopy positions appeared as a single peak and the diurnal variation net photosynthetic rate and stomatal conductance showed a typical curve with a double peak, but the time of the peaks was different. The diurnal change of intercellular CO2 concentration in the three canopies was consistent, as a "U" type curve. The path analysis indicated that photosynthetic available radiation and stomatal conductance were the key factors for the net photosynthetic rate in leaves of the three canopy positions of the E. fordii plantation. The high canopy position's photosynthetic rate, potential photosynthetic capacity, and photosynthetic material accumulating ability were stronger, and less of the photosynthetic product was consumed higher in the canopy than lower in the canopy, which could provide scientific guidance to determine the pruning intensity in E. fordii plantation.
Chlorophyll fluorescence and excitation energy dissipation of pot-grown Phyllostachys rivalis leaves after long-term flooding
LI Yingchun, GUO Ziwu, YANG Qingping, YUE Yongde, CHEN Shuanglin
2017, 34(5): 878-886. doi: 10.11833/j.issn.2095-0756.2017.05.015
[Abstract](2670) [HTML] (438) [PDF](374)
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To determine the physiological and biochemical responses and adaptive mechanisms of Phyllostachys rivalis to long-term soil flooding, two-year-old potted seedlings of Ph. rivalis were subjected to different flooding depths. The flooding treatment was set with water levels of 5 cm (TreatmentⅠ) and 10 cm (TreatmentⅡ) higher than the soil surface and normal water supply (ck). Then the chlorophyll fluorescence parameters in leaves were determined after continuous flooding for 30, 90, 180, 270, and 360 d. Responses to the continuous flooding stress for light energy absorption and transformation, energy transfer and distribution, reaction center activity, and excitation energy dissipation in leaves of three leaves per seedlings and three seedlings were measured and analyzed. A one-way analysis of variance with duncan's test was conducted at a significant level of 0.05. Results showed that the chlorophyll fluorescence parameters varied with different flooding levels. When flooding for 30 d and 90 d, minimal fluorescence (Fo), maximum fluorescence (Fm), photochemical maximum efficiency of PS Ⅱ (Fv/Fm), photochemical quenching coefficient (qP), and electron transport rate(RET) of Treatment Ⅰ were not significantly different (P > 0.05) compared with ck; however, Treatment Ⅱ when flooding for 90 d compared with ck was significantly increased for Fo while significantly decreased for Fm, Fv/Fm and RET (P < 0.05). With flooding treatments of 270 d and 360 d, Fm, Fv/Fm, qP and RET of Treatment Ⅰ and Ⅱ were both significant decreased while Fo were significant increased than that of ck (P < 0.05). The effect of flooding on chlorophyll fluorescence parameters and energy dissipation was also dependent on the water level. In leaves of Ph. rivalis, Fm, Fv/Fm, and qP were significantly decreased (P < 0.05) with continuous flooding stress; whereas, Fo and non-photochemical quenching coefficient (qN) increased gradually but not reached significant level (P > 0.05). The amount of absorbed light in photochemistry (P) and excess energy (E) increased first and then decreased (P < 0.05), but the energy of dissipation of the antenna heat dissipation (D) observed were opposite. Taken together, Ph. rivalis could maintain a relatively high RET, qP, and P in the early stages of flooding, and enhance qN to regulate their energy metabolism, dissipate excess light energy via heat dissipation, thereby alleviating the light photoinhibition and photooxidation; however, continuous long-term soil flooding could damage photosystem Ⅱ (PS Ⅱ) even though there was minimal adverse effect on the functional center of PS Ⅱ (P < 0.05). It can be inferred that Ph. rivalis can tolerate a short term flooding which facilitate its possible application in plantation restoration of riparion zone.
Antioxidant activity of Sophora japonica embryo cells in a suspension culture system
WANG Chenyang, CHEN Hongxian, WANG Mingmei, ZHANG Min, WANG Yimin, LIU Zhonghua
2017, 34(5): 887-894. doi: 10.11833/j.issn.2095-0756.2017.05.016
[Abstract](2574) [HTML] (398) [PDF](291)
Abstract:
To provide a theoretical basis for the structure-activity theory of antioxidant activity for extracted flavonoids, a study was conducted on the antioxidant activity of flavonoid production after a suspension culture of S. japonica embryo cells. Antioxidant activity of crude flavonoids extracted from callus of the S. japonica embryo was not only studied with the method of scavenging hydroxyls, superoxide radicals, and nitrites; but also with the method of inhibiting self-oxidation of linoleic acid and pig oil. Results revealed that when the mass concentration was 354.00 mg·L-1, with an increasing concentration of flavonoids, the free radical scavenging activity (1) of a hydroxyl radical was reinforced with a scavenging ratio on the hydroxyl radical of 96.58%, which is significantly higher than the scavenging activity of vitamin C (P=0.001), (2) of the superoxide radical was reinforced with a scavenging ratio on the superoxide radical of 61.54%, which is much lower than the scavenging activity of vitamin C (P=0.001), and (3) of nitrite was reinforced with a scavenging ratio on nitrite of 79.91%, which is higher than the scavenging activity of vitamin C (P=0.001). (4) The crude flavonoid extract could inhibit the self-oxidation of linoleic acid, which is with an inhibitive effect lower than the scavenging activity of vitamin C (P=0.001) and (5) of the self-oxidation of pig oil was inhibited. Taken together, obvious antioxidant activity was shown in flavonoid production for a suspension culture system of fructus sophoraeembryo cells with a greater concentration of flavonoid extract, for certain ranges of concentrations, having better antioxidant activity.
Soil fauna community after removal of litter and herb layers in an artificial Phoebe zhennan plantation
GOU Liqiong, XIAO Jiujin, HUANG Jinping, LI Ying, WEI Yang, PENG Caiyun, LUO Manli
2017, 34(5): 895-906. doi: 10.11833/j.issn.2095-0756.2017.05.017
[Abstract](2573) [HTML] (467) [PDF](309)
Abstract:
As a main component of soil ecosystems, soil fauna play an important role in the process of soil element cycling, transformation, and migration; however, soil fauna diversity is closely related to ground cover which has a tremendous impact on soil moisture and temperature. To reveal responses of the soil fauna community to the loss of the litter and herb layers, soil fauna in a Phoebe zhennan plantation on the western Sichuan Basin border were studied after litter and herb layers were removed. In each sampled area, soil animals were collected by hand, recorded, and put into a container with alcohol. Then they were transported to a laboratory for detailed classification and identification. The meso-and microfauna samples were gleaned by the steel core and stored in special soil fauna sealing bags. Next, all samples were transported to a laboratory within 12 h and were subsequently separated by both the Tullgren and Baermann methods over 48 h. Mesofauna were observed by microscope after 4 h to avoid autolysis of Enchytraeidae. All collected soil fauna were counted and classifiedunder a light microscope and were identified according to the reference of "Pictorial keys to the soil animals of China". The experiments conducted in July and September, based on statistical analytical software SPSS and Excel, a density-group index (DG) was made. Results showed a collection of 4 phyla from 13 classes with 32 orders having 99 families comprising a total of 1 753 individual soil fauna. Also, after removal of the litter and herb layers, decreases in the soil fauna groups from the two experiments and the DG index in July were highly significant (P < 0.01). After a monthwith the liter and herb removals, compared with Control sites, the soil fauna average density decrease significantly (P < 0.01). Thus, the soil fauna community was deeply influenced by loss of the litter and herb layers, which revealed the relations between the underground biodiversity and the plant species.
Influence of aphid-specific pathogen Conidiobolus obscurus on population dynamics of bamboo aphids and the aphid-control effect
LIU Yilai, WANG Jianghong, ZHANG Jing, ZHU Danni, MAO Jiajun, ZHOU Xiang
2017, 34(5): 907-914. doi: 10.11833/j.issn.2095-0756.2017.05.018
[Abstract](2403) [HTML] (495) [PDF](264)
Abstract:
To determine the regulation of Conidiobolus obscurus on population dynamics of four species of bamboo aphids, specifically, Metamacropodaphis bambusisucta, Takecallis taiwanus, Melanaphis bambusae, and Takecallis arundinariae, three temperature-photoperiod regimes of 20-28 ℃ were used along with 12-15 h of light. Results showed that C. obscurus inhibited bamboo aphid populations with the temperature-photoperiod regimes. Data fit models well with C. obscurus-inoculated groups fitting to log-logistic models and the control groups fitting to logistic models. Results also showed outbreak characteristics of population dynamics for healthy aphids with peak aphid densities 18.4-139.2 times larger than initial densities. Especially in the first observation week, bamboo aphids infected with C. obscurus inhibited population development with the number of days needed to double population densities being ten times more than healthy aphid populations. Thus, C. obscurus could help regulate host populations, delay the occurrence of the bamboo aphid population peaks, and provide potential aphid control in bamboo forests.
Surface coating technology for medium density fiberboard
FENG Chen, TONG Hongtuo, WANG Haoqing, LIU Changjie, QIAN Jun
2017, 34(5): 915-920. doi: 10.11833/j.issn.2095-0756.2017.05.019
[Abstract](2883) [HTML] (580) [PDF](305)
Abstract:
To determine the state of spray nozzle and operational parameters for optimization of coating thickness, a homemade automatic spray paint test device(type of spray gun:WA-101-082P) was used, using polyurethane (PU) wood coatings, with the spraying distance between nozzle and workpiece altered. Also, the nozzle jet direction and angle to the surface of the workpiece were varied along with nozzle operation relative to workpiece speed (Orthogonal experiment L9(34))to 36 block size is 800 mm × 200 mm × 15 mm medium density fiberboard (MDF) test specimen surface spraying process. Then, the surface coating film was measured for film thickness, film surface roughness and performance comparison and a comparative analysis was conducted. Results showed that when the air pressure was 0.28 MPa, the spraying distance was 250 mm, the nozzle angle was 30°, and the running speed was 55 mm·s-1 were optimal conditions for obtaining a thin film thickness and favorable uniformity. With these performance characteristics the coating would perform well.
Bionic building of a super-hydrophobic structure of Chinese rose on a bamboo surface
SONG Jiangang, WANG Fapeng, GU Di
2017, 34(5): 921-925. doi: 10.11833/j.issn.2095-0756.2017.05.020
[Abstract](2901) [HTML] (473) [PDF](429)
Abstract:
To overcome defects such as cracks and deformation caused by moisture absorption of bamboo, a super-hydrophobic micro-nano structure of Chinese rose was built on bamboo surfaces through soft lithography using fresh Chinese rose petals as the template and polydimethylsiloxane for a seal. Scanning electron microscopy was used for the analysis. Results of the scanning electron microscopy and water contact angle (WCA) showed that the prepared Chinese-rose-like bamboo samples had a papillary micro structure and a groove shaped nanometer structure with rough surfaces like Chinese rose petals. The WCA of the replicated bamboo surface was 153.5° which was close to that of Chinese rose petals (157.5°), thereby expressing a super-hydrophobic property. At the same time, water droplets could be firmly attached to the surface of the bamboo. Even if the bamboo surfaces were turned 90° and 180°, water droplets did not roll off the bamboo, which showed favorable adhesion. Thus, the bamboo was super-hydrophobic with high adhesion similar to Chinese rose petals; in addition, the super-hydrophobic sample improved in adhesion with coatings.
Stress wave propagation velocity model for different angles in a longitudinal section of standing trees
ZHANG Chunxiao, FENG Hailin, LI Guanghui, WANG Yanfeng, DU Xiaochen
2017, 34(5): 926-933. doi: 10.11833/j.issn.2095-0756.2017.05.021
[Abstract](2387) [HTML] (414) [PDF](297)
Abstract:
To establish a propagation velocity model of stress wave in longitudinal section, standing trees of different species were selected as samples to study their stress wave velocity pattern for different angles in the longitudinal section of wood. Using a theoretical analysis, the velocity model of stress waves in the longitudinal section of wood was built. Then within the Zhejiang A & F University Botanical Gardens, a total of 40 test samples from four species of trees was selected. The experimental ArborSonic 3D stress wave imaging system was used with a comparative analysis of the results to determine the stress wave propagation velocity. Analysis of the model included fitting an equation to a healthy sample and a regression analysis. Results showed that the propagation velocity between any two points in the same section increases with increasing direction angle. And the propagation velocity between any two points in different longitudinal sections is related to the angle between the longitudinal section and the diameter section. Healthy sample test data were fitted to: v(θ, α)/v0kx2+1 (0≤ k≤ 1) where k was dependent on the size of angle α between the longitudinal section and the radial section of the tree under test. In the established regression model the R2 > 0.93 indicated that the model had ahigh goodness of fit. For different species, due to different internal characteristics, stress wave velocities also differed. The propagation law of stress wave in longitudinal section is related to the direction angle θ and α. θ determines the velocity, and α determines the velocity change, which means the size of the quadratic coefficient k of the fitting equation. For the longitudinal section of healthy trees, θ and α and v(θ, α)/v0 satisfied the geometric relationships: f(θ, α) =1+{[vl-(-0.2α2+1)vR]/vlθ2. Overall, detection results of different species showed the validity of the model which could have important practical applications for nondestructive testing of wood.
Research on the mechanism and strengthening of OLAND process
LAI Zhenggang, CHU Shuyi, CUI Lingzhou, XIAO Jibo
2017, 34(5): 934-941. doi: 10.11833/j.issn.2095-0756.2017.05.022
[Abstract](2730) [HTML] (631) [PDF](354)
Abstract:
Oxygen-limited autotrophic nitrification-denitrification (OLAND) is an new biological nitrogen removal process based on partial nitrification coupled with anaerobic ammonia oxidation. Compared with conventional biological nitrogen removal methods, OLADN has various advantages such as shorter hydraulic retention time, negligible sludge production, no need for external carbon source, higher nitrogen removal efficiency, and being able to operate stably at low temperature. Thus, OLAND has good potential and economic value in terms of technological research and development. This review focused on the microbial species, distribution and characteristics in the process at the micro level, and the effects of dissolved oxygen concentration, substrate concentration, pH and temperature on nitrogen removal at the macro level based on the nitrogen removal mechanisms of OLAND process. The strengthening effects of additives such as bamboo charcoal, MnO2 and iron ions and technologies of bacteria fed to the process on nitrogen removal efficiency in the stage of anammox are also discussed. Major focus for future work will be the knowledge of multi-factor cooperation mechanism, strengthening measures and mechanisms of nitrogen removal.[Ch, 2 fig. 52 ref.]
Establishment of RAPD and ISSR markers for wood identification of 16 species of Lauraceae
LUO Jiayan, WANG Ying, ZHONG Wenhan, LIU Haichong, JIANG Huojun
2017, 34(5): 942-948. doi: 10.11833/j.issn.2095-0756.2017.05.023
[Abstract](2471) [HTML] (456) [PDF](320)
Abstract:
Random amplified polymorphic DNA (RAPD) and inter simple sequence repeats (ISSR) techniques were applied to identify 16 species of Lauraceae. The optimized cetyl trimethylammonium bromide (CTAB)-sodium dodecyl sulfate (SDS) method was used to extract wood DNA of 192 trees in the 16 species. RAPD and ISSR techniques were used to amplify DNA of the 16 species. Results showed that eight RAPD primers and six ISSR primers were screened. Through the eight RAPD primers, 165 bands were obtained, among which 153 were polymorphic for a species level polymorphism loci rate of 92.7%. 96 bands were obtained through the six ISSR primers, among which 86 were polymorphic for a species level polymorphism loci rate of 89.6%. DNA fragment size was 100-2 000 bp. These polymorphism bands amplified by 1 or 2 primers could distinguish the wood of these 16 species in the Lauraceae family, providing technical support for wood identification.
Magnetic treatment on rootings of semi lignified twigs of Fraxinus velutina
ZHANG Xinyu, DONG Yufeng, LIU Peiying, LIU Xiumei, ZHU Hong, WANG Huatian
2017, 34(5): 949-954. doi: 10.11833/j.issn.2095-0756.2017.05.024
[Abstract](2374) [HTML] (464) [PDF](240)
Abstract:
This research explored the effect of magnets on the rooting of cutting slips, young seedling growth and biomass accumulation, and nourishing matter content in roots. Using a current year, sprouting branchlet from a cloned 3-year-old female Fraxinus velutina 'Lula-5' tree as cuttage material and three treatments of magnetized water spray (MW), [magnetized water spray (MW) + magnetization blanket (MR)], and non-magnetized water spray (NMW) (the control) an experiment was carried out with a randomized complete block design trial. Results showed that: (1) the cuttage segment rootage ratio and the root effective index for (MW + MR) were greater and highly significant (P < 0.01) compared to the MW and NMW treatments (control). The average diameter and length growth of young sprouting shoots in the (MW + MR) treatment were also significantly higher than MW and NMW treatments (P < 0.05). (2) The fine root length, diameter, surface area, and volume showed no difference for the three treatments; whereas, all root morphology indexes in (MW + MR) and MW treatments were significantly higher than the NMW treatment (P < 0.05). (3) Compared to the control, nutrient content of N, P, K, Ca, Mg, Fe, Mn, Zn, Cu, and soluble sugar in the other two treatments was greater and highly significant (P < 0.01), but Na was lower and highly significant (P < 0.01). In conclusion, magnetization was beneficial for enhancement of the rooting rate, for promoting root growth as well as forbiomass and nutrient accumulation.
Cutting propagation technology and rooting of Clematis finetiana
ZHAO Shuang, LIU Zhigao, FENG Bin, JI Mengcheng
2017, 34(5): 955-962. doi: 10.11833/j.issn.2095-0756.2017.05.025
[Abstract](2224) [HTML] (487) [PDF](299)
Abstract:
To study cutting propagation techniques with one-year-old cuttings of Clematis finetiana and to investigate the dynamic changes in activity of related oxidative enzymes [peroxidase (POD), indoleacetic acid oxidase (IAAO), and polyphenol oxidase (PPO)] as well as the content of soluble sugar, soluble protein, and starch, an L9(34) orthogonal experiment was conducted with four treatments of exogenous hormones, hormone concentration, soaking time, and cutting matrix. Results indicated that rooting of C. finetiana was derived from the cortex. The effects of different exogenous hormones, hormone concentration, soaking time, and cutting matrix on rooting were notable by variance analysis. The best rooting formula was as follows: a matrix of river sand processed with Indole-3-butyric acid (1H-Indole-3-butanoic acid (IBA) 100 mg·L-1 for 2 h producing a rooting rate of 22.7%. In the rooting process, the content of soluble sugar increased during the induction and root growth periods, but decreased during the expression period and the late growth stage. Soluble protein content decreased gradually after cutting reaching a low point when most cuttings rooted. Starch content declined throughout the process. Also, the POD, IAAO, and PPO activities all increased first and then decreased reaching a peak in the early stages of expression. Additionally, greater nutrient content for the test group was found than the control, and peak oxidase activities of test groups arrived 10 d earlier than the control. This demonstrated that exogenous hormones could improve the nutrient utilization and oxidase activities of cuttings.