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25 July 2019, Volume 55 Issue 7
Articles
Response of Radial Growth of Abies faxoniana and Picea purpurea to Climatic Factors in Subalpine of Western Sichuan
Zhao Zhijiang, Guo Wenxia, Kang Dongwei, Cui Li, Zhao Lianjun, Li Junqing
2019, 55(7):  1-16.  doi:10.11707/j.1001-7488.20190701
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[Objective] In order to provide a basis for further revealing the response mechanism of forest ecosystem to climate change in various subalpine areas of western Sichuan, the response relationships of radial growth for Abies faxoniana and Picea purpurea to climate factors at the same altitude and in the same habitatwere explored.[Method] The standard chronologies about A. faxoniana and P. purpurea at the middleand high altitudes in Wanglang Nature Reserve were obtained, and the relationships between the chronologies and climate factors were analyzed.[Result] There was a certain "abruption effect" between the fir radial growth and mean annual temperatures at the middle-altitude after 1990. In the middle-altitude habitat,the growth of both species were significantly negatively correlated with the temperature in the previous growing season (the current July and August) and the precipitation at the end of the current growing season (the current October) (P<0.05).The growth of A. faxoniana was significantly negatively correlated with the temperature and precipitation in the current September (P<0.05), and the growth of P. purpurea was significantly positively correlated with the monthly mean minimum temperature in the current February and current June (P<0.05).In the high-altitude habitat,the growth of both species were significantly positively correlated with the temperature before the growing season (the previous November, the current January and February). Moreover during the current growing season (the current July) and previous growing season (the previous June) (P<0.05).The growth of A. faxoniana was significantly negatively correlated with the precipitation in the current June and the temperature in the previous August (P<0.05). The reliability of the response of each chronology to the monthly climate factors was fully verified by the result of sliding correlation analysis and climate factors analysis.[Conclusion] The "lag effect" of temperature in the previous growing season had a significant effect on tree growth of A. faxoniana and P. purpurea in the middle-altitude habitat and A. faxoniana in the high-altitude habitat. In recent decades, the precipitation at the end of the previous growing season had a significant and stable inhibition effect on tree growth of A. faxoniana and P. purpurea in the middle-altitude habitat and P. purpurea in the high-altitude habitat.
Growth, Survival and Physiological Response of Food Lichens Usnea longissima of Rhinopithecus roxellana to Simulated Nitrogen Deposition
Jia Raozhen, Wang Ming, Wang Chuanhua
2019, 55(7):  17-26.  doi:10.11707/j.1001-7488.20190702
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[Objective] We aimed to investigate the response of growth and survival, and potential physiological mechanisms of Usnea longissima of Shennongjia Mountain to simulated nitrogen deposition. Our result were of value in winter food management of Rhinopithecus roxellana, as well in understanding the succession of lichen flora under condition of increasing nitrogen deposition of that region.[Method] In this study, four in-situ or indoor experiments were performed, in which simulated nitrogen deposition were imposed on thalli and propagules of U. longissima. Thereafter, thalli growth rate and propagule survival rate, adsorption of ammonium and nitrate, thalli N:P ratio and activity of phosphomonoesterase (PME), glutamine synthetase (GS), and nitrate reductase (NR) were determined. Then we analyzed the growth, survival response of U. longissima and its potential mechanisms to simulated nitrogen deposition.[Result] The result showed that thalli growth and propagule survival were significantly impacted when high nitrogen deposition (>32.99 kgN·hm-2a-1) were performed; In contrast, low nitrogen deposition (<20.94 kgN·hm-2a-1) promoted growth of this lichen. We also found that little nitrate was absorbed, while ammonium was absorbed efficiently. Total nitrogen, N:P ratio, activity of PME increased with increased N deposition, indicating that phosphorous limitation occurred when U. longissima treated with higher nitrogen deposition. Activity of GS and NR both responded nitrogen stress in a first up-regulated, and then down-regulated way.[Conclusion] Low N deposition showed a fertilization effect on the growth of U. longissima, high nitrogen deposition could decrease thalli growth and survival of its propagules. The possible mechanisms underlying it was:U. longissima preferred to uptake and accumulate ammonium, meanwhile high nitrogen stress reduced activity of GS and NR significantly. In addition, high nitrogen stress would induce a phosphorus limitation.
Transport and Distribution Characteristics of Photosynthates of Pinus massoniana Seedlings
Deng Xiuxiu, Xiao Wenfa, Zeng Lixiong, Lei Lei, Shi Zheng
2019, 55(7):  27-34.  doi:10.11707/j.1001-7488.20190703
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[Objective] This study aimed to understand the pattern of transport and distribution of photosynthates in Pinus massoniana and the formation process of P. massoniana productivity.[Method] In this study, the 1.5-year-old P. massoniana seedlings were fed with pulse-chased 13C labeling for 4 h, and then the different organs were collected at 0, 2, 5, 17, 24, 72, 120, 168, 216 and 360 h to analyze the 13C levels, to investigate the transport and distribution of recently synthesized photosynthates in the seedlings. Meanwhile, the accumulation of photosynthates (total carbon and non-structural carbohydrate (NSC)) was determined in various organs.[Result] 1) After the labeled photosynthetic products were synthesized in conifers, the labeled photosynthates were found to be transported to the sink organs, however the amount of the transportation gradually decreased with time. It was manifested that most of the photosynthates were transported within 0-24 hours after the labeling, and the transportation was decreased gradually from 24 to 216 hours. In 216 hours, the labeled photosynthates finished outward transport. It was found that more than 59% of the labeled photosynthates were transported to the sink organs within 0-24 hours over the period of 216 hours. 2) After the transport of photosynthates tended to stable, the distribution of recently synthesized photosynthates in each organ was in the order of 1-year leaves > current-year leaves > roots > stem > 1-year branches > current-year branches, which was consistent with the distribution of the biomass, but different from the sink activity, the sink activity was ordered as current-year leaves > current-year branches > 1-year leaves > roots > 1-year branches > stem. 3) The distribution of total carbon and NSC accumulation in various organs was in accordance with the distribution of recently synthetic photosynthates, which was ordered as 1-year leaves > current-year leaves > roots > stem > 1-year branches > current-year branches.[Conclusion] The photosynthates transport rate in P. massoniana seedlings was greater than 0.1 m·h-1, and more than 59% labeled photosynthates were exported to all sink organs within 0-24 hours after synthesis. The accumulation of new synthesized photosynthates in various organs was mostly in functional organs (leaves and roots). This distribution pattern is conducive to the growth of P. massoniana at seedling stage.
Effects of Four Plant Growth Regulators on Rooting of the Softwood Cutting of Magnolia wufengensis
Wang Yi, Jia Zhongkui, Ma Lüyi, Deng Shixin, Zhu Zhonglong, Sang Ziyang
2019, 55(7):  35-45.  doi:10.11707/j.1001-7488.20190704
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[Objective] The aim of this study was to improve the rooting rate of cutting of M. wufengensis, and provide theoretical support and guidance for the rapid propagation, cultivation and promotion of M. wufengensis.[Method] The semi-lignified branches from 5-year-old Magnolia wufengensis seedlings were collected as the propagation materials. A completely randomized block design with two factors, including four types of plant growth regulators of GGR6,NAA,IBA,and IAA, and six concentrations of 200,500,800,1 000,2 000,3 000 mg·L-1,were used. The effects of different types and concentrations of plant growth regulars on rooting parameters of M. wufengensis, i.e. rooting rate, number of adventitious roots, average root length, average root diameter, and root effective traits rate, were investigated. And then the principal component analysis was used to comprehensively evaluate the effects of each treatment combination on rooting.[Result] The results showed that the rooting rate and root morphology of NAA solution treatment was all at a high level among the four plant growth regulators. When the cuttings was soaked in 1 000 mg·L-1 NAA solution, the cutting root had the best quality. The average number of adventitious roots was 13.3, which was 12 more than that of the control group treated with water. The average root length was 14.33 cm, which was about 2.7 times of the control group. The average root diameter was 2.44 mm,which was 0.60 mm thicker than that of the control group. The root effective traits rate was 55.4%, which was 22.1% higher than that of the control group. The rooting rate of NAA 1 000 mg·L-1 treatment was the highest, reaching 53.3%, significantly different from other concentrations, and 16 times higher than that of the control group.[Conclusion] The NAA solution had the better rooting effects than the other three types of growth regulator, and the best concentration of NAA was 1 000 mg·L-1. The research has greatly increased the rooting rate of M. wufengensis, and has provided theoretical basis and technical guidance for the large-scale propagation of germplasm resources of M. wufengensis.
Effect of Retting Temperature on Transformation of Main Nutrients in Seeds of Different Torreya grandis Cultivars during After-Ripening Period
Shan Yanfei, Wang Weiyu, Xiang Weixia, Song Lili, Zhou Minyin, Chen Jiawei, Suo Jinwei, Yu Weiwu, Wu Jiasheng, Hu Yuanyuan
2019, 55(7):  46-56.  doi:10.11707/j.1001-7488.20190705
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[Objective] This study aimed to investigate the transformation of nutrients in seeds of different Torreya grandis cultivar sand the change characteristics of its after-ripening qualityby comparing the changes in main nutrients of the wild, half cultivated and cultivated T. grandis seeds during after-ripening period under different retting temperatures.[Method] Two retting temperature were applied in this study. The seeds of four T. grandis cultivars (cultivated seeds:T. grandis ‘Zhuyan’ and T. grandis ‘Dingxiang’,T. grandis ‘Dong No.3’; wild seeds:T. grandis Fort. Ex. Lind)were used as experimental materials to determine the changes in the inter seed coat color, starch content, soluble sugar content,soluble protein content, oil content and fatty acid compositions during after-ripening period under the two different retting temperature conditions.[Result] 1) The inter seed coat color of the four T. grandis cultivars changed from red to dark brown after 20 days of treatment with T20. Except for T. grandis Fort. Ex. Lind, the inter seed coat color of the other three T. grandis cultivars was turned to dark brown after 10 days of treatment with T30. 2) Before the retting treatments, the starch content in seeds of T. grandis Fort. Ex. Lind and T. grandis ‘Dingxiang’ was significantly higher than that in the other two cultivars. Compared with before retting treatment, the starch content of three T. grandis cultivars dramatically decreased after 20 days of treatment with T20 and 10 days of treatment with T30 except that the starch content of T. grandis Fort. Ex. Lind seeds did not chang significantly. 3) The soluble protein content in seeds of T. grandis ‘Zhuyan’ and T. grandis ‘Dong No.3’ was significantly higher than that in T. grandis ‘Dingxiang’ and T. grandis Fort. Ex. Lind. In comparison with before retting treatment, the soluble protein of the seeds of three T. grandis cultivars except for T. grandis Fort. Ex. Lind dramatically decreased after treatment with T20 for 20 days, and the soluble protein of three T. grandis cultivars except for T. grandis ‘Zhuyan’ significantly increased after treatment with T30 for 10 days. 4) The oil content and unsaturated fatty acid content in seeds of the four T. grandis cultivars were in the order of T. grandis ‘Dingxiang’ > T. grandis ‘Dong No.3’ > T. grandis ‘Zhuyan’ > T. grandis Fort. Ex. Lind.In comparison with before retting treatment, the oil content and unsaturated fatty acid content in the seeds of four T. grandis cultivars significantly increased after treatment with T30 for 20 days. The oil content and unsaturated fatty acid content were significantly higher in T. grandis ‘Dingxiang’ and T. grandis ‘Dong No.3’ than those in the other two T. grandis cultivars, with T. grandis Fort. Ex. Lind the lowest, after treatment with T30 for 10 days.[Conclusion] It was indicated that the seed quality ofthree cultivated T. grandis was better than that of the wild T. grandis before retting treatment. After retting treatment,the starch content in seeds of the four T. grandis cultivars significantly decreased, while the oil content significantly increased. The increase of the oil content in T. grandis ‘Dong No.3’ was significantly higher than that in the other three T. grandis cultivars after retting treatment, and the increase of the oil content in T. grandis Fort. Ex. Lind was lowest among the four T. grandis cultivars. Although, the response of the four T. grandis cultivars to different retting temperature were different, the higher retting temperature significantly accelerated the after-ripening process of seeds of the four T. grandis cultivars by increasing decomposition of starch and synthesis of proteins and lipid.
Comparisons of Genetic Variation and Gains of 6-year-old Families from First-and Second-Generation Seed Orchards of Pinus massoniana
Jin Guoqing, Zhang Zhen, Yu Qixin, Feng Suiqi, Feng Zhongping, Zhao Shirong, Zhou Zhichun
2019, 55(7):  57-67.  doi:10.11707/j.1001-7488.20190706
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[Objective] To evaluate genetic gain and effect of improvement of the first-and the second-generation clonal seed orchards of Pinus massoniana, and to provide guidance for the breeding, production and application of the genetically improved P. massoniana.[Method] Two 6-year-old progeny trials of open-pollinated families of P. massoniana using materials respectively from the first-generation and the second-generation seed orchards in Zhejiang Chun'an and Fujian Shaowu were measured for evaluation of growth performance, analysis of genetic variation and gains, and estimation of breeding values of the families.[Result] There are large differences between progenies from different generations of seed orchard, while major growth traits including tree height, DBH, and volume all were higher than those of the control (i.e. the bulk selection from superior natural stands). The average individual volume and breeding value of the progenies from the first-generation seed orchard were 55.78%-84.62% and 40.66%-71.39% higher than those of the control, while these values were 58.96%-108.97% and 42.97%-91.89% for the progenies from the second-generation seed orchard. In general, progenies from the second-generation seed orchard exhibited greater growth rate and higher genetic stability than that of the first-generation seed orchard. There were significant differences in major growth traits among progeny families of the same generation. Tree height, DBH, and volume of the best family from the first-generation seed orchard were 21.94%, 30.72% and 97.75% higher than that of the poorest family. The traits of the best family from the second-generation seed orchard were 23.42%, 29.60% and 90.09% higher than that of the poorest family. These results indicated that re-selection of the parental lines from seed orchard will be essential. The tested families were classified into four types, i.e. "fastest-growing", "fast-growing and stable", "fast-growing and unstable", and "slow-growing", which accounted for 23.68%, 26.32%, 21.05% and 28.95%, of the total number of families respectively. The types of "fastest-growing" and "fast-growing and stable" could be used for establishing the new second-generation clonal seed orchard. Interactions of site×family and block×family were detected, indicating that the growth performance of families were diverse across different environment.[Conclusion] The effect of genetic improvement of progenies from the clonal seed orchard of P. massoniana was outstanding, and genetic gain of the second-generation seed orchard was larger than that of the first-generation seed orchard. Selecting the "fastest-growing" and "fast-growing and stable" parental lines is suggested in the selective-thinning of the old seed orchard and the establishment of the new seed orchard. The utilization of the singular-line parent with superior growth performance and high yield of seeds is suggested, mainly due to the interaction of environment×genotype and the diverse growth performance of families across different environments.
Genetic Parameters for Growth Traits in Eucalyptus urophylla×E. grandis F1 Hybrids
Shen Le, Xu Jianmin, Li Guangyou, Lu Zhaohua, Yang Xueyan, Zhu Ying, Hu Yang, Song Peining, Guo Wenzhong
2019, 55(7):  68-76.  doi:10.11707/j.1001-7488.20190707
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[Objective] Multiple-year growth traits of Eucalyptus urophylla×E. grandis F1 hybrids were investigated, their genetic parameters were estimated, and superior hybrids and plus trees were selected aiming to provide a scientific basis for selection of mating parents and their hybrids.[Method] The F1 hybrids of E. urophylla×E. grandis from factorial mating system were studied using the open-pollinated progenies of E. urophylla as controls. ASReml-R software was applied to assess heritability, dominance effect,additive effect, parental effect and combining abilities of growth traits when 1, 2, 4.5, 8.3 and 10.3 years old. Mean single-tree volume was calculated for each hybrid combination, and superior combinations were determined as those with volume above mean+standard deviation of all combinations. Selection of plus trees was conducted with two standards, I:mean + two times standard deviation, and Ⅱ:mean + three times standard deviation.[Result] Growth performance of hybrids was obviously better than that of open-pollinated maternal off-springs at each age. Tree height, diameter at breast height (DBH) and individual volume at each age were significantly (P<0.05 or P<0.01) different among hybrid combinations, while no significant difference was observed among blocks. Maternal variance component of each growth trait was lower than paternal variance component when one or two years old, they were equivalent to each other when 4.5 years old, while maternal variance component was higher than paternal variance component when 8.3 or 10.3 years old. With age increase, single-tree heritability (h2) generally tended to vary from middle to low, family heritability (hF2) from high to middle to low, while additive-to-dominance variance ratio (σD2/σA2) increased for tree height and DBH. Year-year and trait-trait genetic and phenotypic correlations were significant among hybrids. The general hybridizing abilities (GHA) of U21 and G8 were the highest among maternal and paternal parents, respectively, and the specific hybridizing ability (SHA) of U21×G5 was the highest among all cross combinations when 4.5 years old. When 8.3 years old, GHA of U21 and G19 were the highest, and SHA of U2×G19 was the highest.[Conclusion] Maternal and dominance effect of each growth trait was lower than paternal and additive effect when one or two years old, respectively,maternal and paternal effect were equivalent to each other when 4.5 years old, while maternal and dominance effect was higher than paternal and additive effect when 8.3 or 10.3 years old. A total of 7 superior cross combinations, one superior maternal parent and two paternal parents were selected, and 40 and 16 elite individuals were determined according to Standards I and Ⅱ, respectively. The findings can provide reliable parent materials for a large number of artificial seed production and clones for eucalypt extension in the future.
Expression and Function of CpWOX13 Gene in Chimonanthus praecox
Li Zhineng, Jiang Yingjie, Chen Jing, Li Ting, Sui Shunzhao, Li Mingyang
2019, 55(7):  77-85.  doi:10.11707/j.1001-7488.20190708
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[Objective] WOX13 gene is a member of the ancient clade of the transcription factor of WOX (WUSCHEL related homeobox),which is mainly involved in the regulation of floral transition and root development. In this study,the expression patterns and overexpression phenotypic traits in Arabidopsis thaliana were analyzed to explore the gene function of CpWOX13 and also to provide a basis for comprehensive research on the mechanism of WOX13 genes in different species with low phylogenetic status.[Method] Based on the RNA-seq analysis at three different developmental stages (petal appears,flowering peak and declining) in Chimonanthus praecox ‘grandiflorus’,CpWOX13 gene was obtained by Reverse Transcription Polymerase Chain Reaction (RT-PCR). Phylogenetic tree was constructed by Neighbor-joining (NJ) method. CpWOX13 expression analysis in flower bud in April,May,July and September (4FB, 5FB, 7FB, 9FB) was carried out using quantitative real-time RT-PCR (qRT-PCR). The genetic effects of CpWOX13 on plant development were explored by studying the phenotypes, including rosette leaves,length of axial and lateral root and plant height between the 35S∷CpWOX13/Col-0 Arabidopsis lines and the wild type.Relative gene expression of CpWOX13 and endogenous gene from Arabidopsis was also carried out in three overexpression lines and WT by qRT-PCR.[Result] CpWOX13 clustered closely to WOX13 in Vitis vinifera and Arabidopsis, belonging to ancient clade of WUS family. qRT-PCR indicated that CpWOX13 transcripts were found at different developmental stages,4FB,5FB,7FB and 9FB.The highest CpWOX13 expression was observed in 5FB, nearly 6.5-fold higher than that of 4FB,and about 3.8-and 3.3-fold of 7FB and 9FB,respectively. Phenotypes were observed in different 35SCpWOX13/Col-0 lines compared with the Col-0. 35SCpWOX13 overexpression (OE) lines (OE6#,OE3# and OE8#)induced early flowering,in which the number of rosette leaves was slightly less than that of Arabidopsis Col-0. In addition,the length of axial root and the number of lateral root of transgenic lines increased significantly,the plant height was much higher than that of the wild type,with a maximum of 12 cm.[Conclusion] CpWOX13,one of the WOX family homologous genes,expressed in different developmental stages of C. praecox. The highest expression was detected in flower bud during the differentiation of stamen and pistil primordia in May.Overexpression of CpWOX13 affects the development of lateral root and results in early flowering in transgenic Arabidopsis.
Biomass Dynamic Predicting for Schima superba in Guangdong Based on Allometric and Theoretical Growth Equation
Xue Chunquan, Xu Qihu, Lin Liping, He Xiao, Cao Lei, Li Haikui
2019, 55(7):  86-94.  doi:10.11707/j.1001-7488.20190709
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[Objective] In order to predict the biomass dynamic for Schima superba in Guangdong, a method of model system of combining the theoretical growth equation and the allometric equation was proposed and fitted. The method will provide the method ological support to other tree species for measuring carbon sink.[Method] Based on the measuring biomass survey data of sample trees, including 40 large trees whose stem were analyzed, this paper established the model system from theoretical growth equation which related DBH (diameter at breast height) to age and allometric equation which related aboveground biomass to DBH. Using nonlinear error-in-variable simultaneous equations, the models were fitted and the parameters were estimated under the classificated parameters which described DHB' growth rate. Based on three periods data of the sample trees in the permanent sample plot in China national forestry inventory, biomass dynamics for Schima superba were predicted in Guangdong province. Determination coefficient (R2) and root mean square error (RMSE) were used to evaluate the model and estimate error for biomass storage and increment were used to assess the prediction.[Result] By classificated parameters for DHB growth, the explanation of theoretical growth equation for DBH was more than 0.95, raised 0.166 3 than that of the model with fixed growth parameter, RMSE reduced above 2.16 to 1.97 cm. The explanation of aboveground biomass with predicted DBH was 0.82, improved 0.30 than that of the model with fixed growth parameter, closely to R2 of independent allometric model, and RMSE reduced more than 30 to 51 kg. The estimated errors for different biomass storages ranged from -46.31% to 77.45% by the model with fixed growth parameter, while the estimated errors reduced from -16.13% to -7.06% in the case of the model with classificated parameters. There was same law at different scales for the two models, the estimated error for single tree were lower than that for stand and the estimated error for stand was lower than that for region. The error difference between single tree and region were not greater than 10% by the model with fixed growth parameter, while it was lower than 8% by the model with classificated parameters. The estimated errors for biomass increment at different periods were generally larger which varied from 32.57% to 115.45% by the model with fixed growth parameter, while the errors reduced from -6.57% to 15.77%,even less than ±10% at tree level, by the model with classificated parameters. With enlarging of scale, the estimated errors increased, the error differences between single tree and region varied from 10% to 15% by the model with fixed growth parameter and the differences were relatively stable around 8% by the model with classificated parameters.[Conclusion] By means of the combination model system of theoretical growth equation and allometric equation, classification could significantly improve the model accuracy and reduce the estimated error for prediction. Only DBH or age in the case of the model with fixed growth parameter, two-stages DBH or DBH and age of same period in the case of with classificated parameters could be used to predict the biomass dynamic in the future. The method and models were easy to use and had a promising applicative value to the estimation of carbon sink national forestry inventory and afforestation of carbon sink,the estimated error at regional scale could basically satisfy the accuracy requirements.
The Characteristics of Needle Blight of Pure Pinus densiflora Forests in Kunyushan Mountains and Its Relationship with Forest Factors
Hu Ruirui, Liang Jun, Xie Xian, Huang Yonghuai, Wang Jun, Yuan Xiaowen, Zhang Yingjun, Zhang Xingyao
2019, 55(7):  95-104.  doi:10.11707/j.1001-7488.20190710
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[Objective] The purpose of this paper was to analyze and evaluate the effect of forest factors on the occurrence of pine needle blight (DI and DSI) quantitatively, thus to provide theoretical guidance for the forest management and prevention of the pine needle blight in pure forests of Kunyushan Mountains.[Method] Pinus densiflora pure forests with relatively consistent forest age (about 34 a) were targeted as the research object in Kunyushan Mountains. Six forest indexes, including forest density, canopy cover, tree height, height under branch, diameter at breast height (DBH) and crown cover, as well as the disease incidence (DI) and disease severity index (DSI) of the pine needle blight were investigated. Variance analysis, correlation analysis and multiple comparisons were used to analyze the relationship between forest factors and pine needle blight. The key factors affecting the occurrence of needle blight were obtained by redundancy analysis.[Result] Pine needle blight was prevalent in P. densiflora forests, with 96.3% of the sample plots being infected. Overall, the DI and DSI in high density forests (2 956~4 089 tree·hm-2) were significantly higher than low density forests (688~1 822 tree·hm-2) and middle density forests (1 823~2 955 tree·hm-2). DI and DSI in low canopy cover forests (< 30%) were significantly lower than that of middle canopy cover forests (30%-70%) and high canopy cover forests (> 70%). In different groups of tree height, height under branch, crown cover and DBH, the DI and DSI decreased with the increase of group values. Results from regression analysis and multiple comparisons showed that forest density affected disease incidence (DI) and disease severity index (DSI) positively and significantly (r=0.761, P< 0.01; r=0.748, P < 0.01). The disease incidence and disease severity index were affected by canopy cover significantly and positively (r=0.509, P < 0.01; r=0.442,P < 0.01). Tree height had significant influence on the disease incidence and disease severity index (r =-0.443, P<0.01; r =-0.362, P <0.01). The disease incidence and disease severity index decreased with the increase of the height under branch significantly (r =-0.460,P <0.01;r =-0.419,P <0.01). They also were negatively correlated with diameter at breast height, and the correlation was extremely significant (r=-0.425, P<0.01; r=-0.373, P<0.01). The disease incidence and disease severity index decreased significantly with the increase of crown cover (r=-0.345, P<0.01; r=-0.381, P<0.01). Redundancy analysis proved that forest density and height under branches contributed the most to occurrence of pine needle blight.[Conclusion] The occurrence of pine needle blight is relatively common but not serious in Kunyushan Mountains region. The disease incidence and disease severity index are different in different forest factors groups, and they are highly significantly influenced by the forest factors. RDA analysis shows that forest density and height under branch have the most significant impact on pine needle blight. It is suggested that the control of needle blight in pure Pinus densiflora forests in Kunyushan Mountains should be controlled mainly by important factors by conducting reasonable pruning and thinning.
A New Bambusa chungii Feeding Species of the Genus Mukaria Distant (Hemiptera: Cicadellidae: Deltocephalinae: Mukariini) from China
Yao Yalin, Chen Xiangsheng, Yang Lin
2019, 55(7):  105-110.  doi:10.11707/j.1001-7488.20190711
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A new bamboo-feeding species of the genus Mukaria Distant (Hemiptera:Cicadellidae:Deltocephalinae:Mukariini), M. hainanensis sp. nov., is described and illustrated. The new species was collected on bamboo (Bambusa chungii)from Jiangfengling National Natural Reserve, Hainan Province, China. The new species is closely related to M. ablinotata Cai & Ge, 1996, but can be distinguished by the characters below:forewing yellowish brown; ventral process of male pygofer long and sinuate, turning outside apically at ventral view; male aedeagus without process between two shafts, inside process of shaft near apex stout and straight. In this paper,the external morphological characteristics of the new species are described in detail.A key to Chinese species of the genus Mukaria is compiled, and the photograph illustrations of the new species and M. ablinotata, colour photographs of new species and its host plants are provided. The type specimens of the new species are deposited in the Institute of Entomology, Guizhou University, Guiyang, China.
Population Dynamics of Grapholitha molesta(Lepidoptera: Tortrididae) and Control Effects by Sexual Pheromone in Apple Orchards with Non-Bagged-Fruit Cultivation Pattern
Zhai Hao, Wang Jinzheng, Xue Xiaomin, Wang Laiping, Chen Ru, Nie Peixian, Zhang Yong
2019, 55(7):  111-118.  doi:10.11707/j.1001-7488.20190712
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[Objective] The aim of this study is to reveal the population dynamics of Grapholitha molesta (Lepidotera; Tortricidae) and control effect by sexual pheromone on mating disruption of the pest in the apple orchards with the non-bagged-fruit cultivation pattern.[Method] The occurrence dynamics of G. molesta in the field and the rate of bored fruits in non-bagged-fruit cultivation orchards were monitored via sexual pheromone inducer in Yantai, Weihai and Tai'an respectively. According to the occurrence dynamics, the control effect of sexual pheromone was explored by releasing the sexual pheromone in eclosion prophase of the overwintering generation, the first generation and the second generation.[Result] The result showed that the adults of G. molesta in 2017 emerged from mid or late March to early April in Yantai, Weihai and Tai'an, and ended in early October. There were five obvious occurrence peaks, which were concentrated from July to September. The year-round number of G. molesta caught by sexual pheromone (ranging from 213 to 1837 insects per trap) in non-bagged apple orchards of three regions was significantly lower than that in bagged orchards (ranging from 729 to 3715 insects per trap) (P<0.05). However, the rate of bored fruits in non-bagged apple orchards (ranging from 3.38% to 6.13%) was significantly higher than that in bagged orchards (ranging from 0.13% to 0.50%) (P<0.05). In bagged apple orchards, sexual pheromone released in eclosion prophase of the overwintering generation, the first generation and the second generation all exhibited obvious disruption effect on the mating action of G. molesta male adults, however, the rates of mating disruption in different periods were significantly different (ranging from 87.28% to 99.80%) (P<0.05). In the larvae damaging peak of G. molesta (the fifth generation) from September 11 to October 8, the control effect of sex pheromone that was released before the first generation and the second generation eclosion (respectively being 92.89% and 95.53%) of Grapholitha molesta were significantly higher than that was released before the winter overwintering eclosion (81.77%) (P<0.05).[Conclusion] There was no significant difference in the occurrence dynamics, peak period of adults and duration between the bagged and non-bagged apple orchards in Yantai, Weihai and Tai'an, but the damage of G. molesta in non-bagged apple orchards was significantly more serious than that in bagged orchards. In non-bagged orchards, the combination of sex pheromone and chemical pesticide was more effective than single chemical pesticide, and the sex pheromone released before the first generation and the second generation eclosion of G. molesta obtained the best control effect.
Sorption Isotherms Characteristics of High Temperature Heat-Treated Wood
Gao Xin, Zhou Fan, Zhou Yongdong
2019, 55(7):  119-127.  doi:10.11707/j.1001-7488.20190713
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[Objective] The effects of high temperature heat treatment on the equilibrium moisture content and sorption isotherms characteristics of Pinus sylvestris var. mongolica,Cunninghamia lanceolata and Populus nigra were studied. The research result could be used in scientific evaluation of moisture adsorption characteristics of wood, and the relevant data could also be used as a reference in actual production.[Method] In this study water vapor was used as protective medium and three levels of heat treatment temperature were set, which was 180, 200 and 220℃, respectively. The sorption experiments were performed in the two-chamber setup, the relative humidity of air was controlled by eight kinds of salt solutions and the air temperature of sorption experiments were 25℃. The sorption isotherms of high temperature heat-treated wood was fitted by Hailwood-Horrobin equation, and the effects of high temperature heat treatment on the isothermal adsorption behavior, equilibrium moisture content, monolayer water and polylayer water were analyzed.[Result] The equilibrium moisture content of 180, 200, 220℃ treated samples were equivalent to 80%, 70% and 50% equilibrium moisture content of control samples, respectively. The Hailwood-Horrobin equation could be used to fit the isothermal adsorption curves of three species wood and their high temperature heat-treated wood, and their isothermal adsorption curves all belonged to typeⅡ, the fitting degree of isothermal adsorption curves were higher than 0.980 0 for all the conditions. The higher the treatment temperature was, the closer the isothermal adsorption curve is to the straight line. The parameter W which means the apparent molecular mass of the dry wood per sorption sites was significantly increased after heat treatment, meanwhile, the moisture content of monolayer and polylayer water in different relative humidity environment was significantly decreased after heat treatment. The monolayer water of samples reduced about 20%, 30% and 50% for 180, 200, 220℃ heat-treated wood comparing with those of control samples, respectively. The influence of high temperature heat treatment on polylayer water was similar. The maximum amount of monolayer water, polylayer water and the total amount of adsorbed water was significantly reduced compared with control samples after heat treatment, and the higher the treatment temperature, the greater degree of decline was found.[Conclusion] The equilibrium moisture content of wood could be significantly reduced by high temperature heat treatment, and the higher the treatment temperature, the greater the decreasing in the equilibrium moisture content was obtained. The Hailwood-Horrobin equation could be used to describe the isothermal adsorption curve of high temperature heat treatment wood, and the fitting degree is fairly high. The isothermal adsorption curve of wood could be significantly influenced by high temperature treatment. The amount of monolayer water, polylayer water and total adsorbed water could be significantly reduced by high temperature heat treatment, and the higher the treatment temperature, the more obvious of the influence was found. The maximum content of monolayer water, polylayer water was significantly reduced after heat treatment, which would affect the maximum amount of adsorbed water.
Investigation of the Mechanical Behavior of Wood-Adhesive Interphase by Using Nanoindentation
Wang Xinzhou, Xie Xuqin, Wang Siqun, Li Yanjun, Liang Xingyu
2019, 55(7):  128-136.  doi:10.11707/j.1001-7488.20190714
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[Objective] The effects of the penetration of resin on the mechanical properties of wood cell wall in the interphase region were studied systematically, which provided the theoretical basis for the optimization of the manufacturing technology and the enhancement modification of wood-based composites.[Method] The elastic modulus, hardness, creep properties, dynamic storage modulus, and dynamic loss modulus of wood cell walls from loblolly pine (Pinus taeda)and resins (phenolic resin and urea-formaldehyde resin)in the interphase region were investigated by the means of nanoindentation and nanoscale dynamic mechanical analysis (Nano-DMA).[Result] In the static mechanical behavior, the effective penetration of resin contributed greatly to the elastic modulus (Er)and hardness (H)of cell wall of wood tracheid in the interphase region. In the interphase of wood-PF, the elastic modulus (Er)and hardness (H)of loblolly pine cell wall increased by 7% and 26%, respectively. The curve fitting goodness of fit (coefficient of determination squared value R2)was greater than 0.97, indicating Burgers model can be used to describe the mechanical indentation creep characteristics of wood tracheid cell walls. The instant elastic modulus of the wood cell wall in the interphase increased, while the viscoelastic modulus and the viscosity decreased after being penetrated with resin. In the initial period of load holding, the creep compliance of the wood cell wall decreased by about 60% and 58% after being penetrated by PF resin (phenolic resin)and UF resin (urea-formaldehyde resin), respectively, as compared to the control cell wall. In the dynamic mechanical behavior, with the increase of the loading frequency, the storage modulus E'r of the interphase increased gradually, while the loss modulus Er and loss tangent tan δ decreased. When the loading frequency was 10 Hz, the storage modulus of the cell wall layer of wood tracheid penetrated with PF resin and UF resin increased by about 16% and 29%, respectively.[Conclusion] The penetration of resins made a great contribution to the elastic modulus, hardness, and short-term creep resistance of wood cell wall. The important dynamic mechanical parameters obtained by Nano-DMA indicated that wood cell wall had a higher storage modulus and loss modulus as compared to that of the adhesives. The storage modulus of the cell wall penetrated with adhesive had an increase in comparison to the control cell wall, while the loss modulus and loss tangent showed a decreasing tendency, which will have negative effect on stress transfer and dispersion in the interphase region of wood-based composite.
Hygrothermal Strain Response of Bamboo Culm
Yan Wei, Zhang Bin, Fu Wansi, Zhou Jianbo
2019, 55(7):  137-145.  doi:10.11707/j.1001-7488.20190715
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[Objective] Environmental temperature and relative humidity (RH)play important roles in dimension deformation and physical mechanical properties of bamboo culm, the investigation of strain property of bamboo culm can provide a basis for dimensional stability and environmental adaptability of bamboo culm utilization in original status.[Method] Annual mean temperature and RH of six cities in China were selected and analyzed to research hygrothermal strain behavior of bamboo culm (Phyllostachys edulis). Bamboo culms with similar diameter (96.52 mm±1.46 mm)and different lengths (500,400,300 and 200 mm)were placed in test chamber undergoing the temperature and humidity environment which were successively changed with six stages (5℃,66%; 13℃,50%; 20℃,70%; 20℃,80%; 30℃,80%; 9℃,36%). The circumferential strain value of the top and middle parts and the axial strain value of bamboo culm were collected by static strain indicator, and the influence of temperature, humidity and length on bamboo culm response behavior were analyzed and discussed.[Result] The initial value of strain was set as zero, and the bamboo culm was shrinkage from laboratory environment to test chamber, the strain value was negative. Subsequently, the bamboo culm showed swelling with the increase of temperature and humidity for moisture adsorption, and the strain value was positive. Swelling strain value was declined quickly and even indicated shrinkage with the sharp decrease of temperature and humidity. Circumferential strain value range was -500-3 000 με,while axial strain value ranged from -50 to 225 με. Especially, the circumferential strain of top part displayed more sensitive to the temperature and humidity change, while the strain of middle part was hysteresis. The max strain difference between top and middle parts of bamboo culm with length of 500 and 400 mm was significantly larger than that of bamboo culm with length of 300 and 200 mm. The difference values of bamboo culm with length of 300 and 200 mm changed from positive to negative, and the strain displayed wane and wax.[Conclusion] Bamboo culm could make immediately response to environment changes, temperature, humidity and length had significant impacts on the swelling and shrinkage strain behaviors of bamboo culm and the influences of temperature were always reflected by humidity which was associated to moisture content of bamboo culm. Circumferential strain behavior was similar with that of axial strain, while its value was obviously greater than axial strain value, top part of bamboo culm was more sensitive to temperature and humidity, and the longer length means more strain difference between top and middle parts. The stress unequilibrium in longer bamboo culm induced by moisture element adsorption and release is the main reason for bamboo culm deformation and rupture.
Comparison of the Anatomy Structure and Chemical Compositions of Agarwoods from Two Kinds of Aquilaria sinensis
Wang Jun, Wang Yuguang, Yang Jinling, Li Wei, Dong Wenhua, Mei Wenli, Dai Haofu
2019, 55(7):  146-154.  doi:10.11707/j.1001-7488.20190716
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[Objective] After using nailing method to induce the new variety Aquilaria sinensis ‘Reke 1’ and the common Aquilaria sinensis to produce agarwood for two years, we compared the differences of them.[Method] Wood anatomical method was used to observe the three sections of wood, wood tissue structure of the two kinds of agarwoods were observed by means of macroscopic and microscopic perspectives. The chemical compositions of two kinds of agarwoods were checked by GC-MS method and a comparative analysis was made.[Result] 1) The new variety agarwood color was yellowish brown, the volume of the former agarwood was bigger than common Aquilaria sinensis and also can produce agarwood easily. The Aquilaria sinensis ‘Reke 1’ has weak ability to repair trauma, its agarwood substance was mainly accumulated in vessel and axial parenchyma. But the common Aquilaria sinensis has strong ability to repair trauma, its agarwood substance was mainly accumulated in ray parenchyma cells and included phloem. 2) GC-MS result indicated that the total relative contents of chromones and sesquiterpenes for Aquilaria sinensis ‘Reke 1’ and common Aquilaria sinensis were 75.88% and 70.41% respectively, the primary constituents of the former agarwood were chromones, and the contents of chromone and sesquiterpene in the latter agarwood were about the same relevant amount. 3) The sum relative contents of compound 2- (2-phenylethyl)chromone and 2-[2-(4-Methoxy)phenylethyl] chromone, which was the ingredient of classy agarwood, were 25.19% and 5.97% respectively in Aquilaria sinensis ‘Reke 1’ and common Aquilaria sinensis. The former is about 4.22 times higher than the later.[Conclusion] By comprehensive analysis, it illustrate that the quality of agarwood from Aquilaria sinensis ‘Reke 1’ was better than the others, and Aquilaria sinensis ‘Reke 1’ was the superiorities of easier to produce agarwood, higher yield of agarwood, better quality of produced agarwood than the common Aquilaria sinensis. It was worthy of further cultivation and evaluation.
Review
Research Advances in Forest-Runoff Relationship
Liu Xiaodong, Liu Peiling, Dai Yuhang, Mo Qifeng, Lin Haojuan, Li Jiyue, Zhang Qianmei, Chen Xiuzhi
2019, 55(7):  155-162.  doi:10.11707/j.1001-7488.20190717
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The effects of forest cover change on water yield, a hotspot as well as a difficult issue in the fields of forestry, ecology and hydrology, still exist great debate. Observations of numerous watershed experiments that have been conducted for a century throughout the world also vary greatly and remain controversial. Here, based on the observations of globally published paired-watershed experimental and the time-trend result, we comprehensively presented the divergent opinions on the effects of forest cover change on water yield and analyzed the potential underlying mechanism. After that, we further summarized four aspects which need to be emphasized in future studies:1) to develop carbon and water coupling research at multiple scales; 2) to develop multiple sites and cross-regional integration research; 3) to concentrate on hydrological and ecological processes, mechanism and modeling; 4) to strengthen the cross-penetration and integration of different disciplines and technical fields studies.
Scientific notes
Composition and Spatial-Temporal Variation of the Seed Rain in An Evergreen Broad-Leaved Forest on Jinyun Mountain
Xiao Jing, Huang Li, Yang Chao, Li Xiaohan, Wu Xiaoqi, Zhou Lihua, Qian Shenhua, Yang Yongchuan
2019, 55(7):  163-169.  doi:10.11707/j.1001-7488.20190718
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[Objective] This study aims to investigate the composition and spatial-temporal variation of the seed rain in an evergreen broad-leaved forest in Jinyun Mountain. This study also aims to provide data support for large-scale and long-term ecological studies on seeds in evergreen broad-leaved forests, as well as to guide the collection of seed sources and to learn the patterns of seed dispersal during the restoration of damaged forests.[Method] Seeds were collected from January 2014 to December 2016 using 172 seed traps established in a 1hm2 monitoring plot in Jinyun Mountain. Collected seeds were identified and counted, and seed mass was weighted after being air-dried.[Result] 36 298 mature seeds belonging to 27 species of 21 genera and 19 families were collected in three years. The density of the seed rain was 140.69 seeds·m-2 a-1. The 27 species accounted for 36.49% of the total number of woody plants within the study plot. The seed rain showed a clear seasonal dynamics and the peak of the seed rain appeared in autumn; 17 species released mature seeds in the dry season (from January to April and from October to December), while 6 species released mature seeds in the wet season (from May to September) and 4 species released mature seeds in both dry and wet seasons. The coefficient of interannual variation of the seed rain ranged between 0.36 and 1.73, and the coefficient of spatial variation of the seed rain ranged between 1.54 and 15.20.[Conclusion] Seed production in Jinyun Mountain was relatively low compared with the other evergreen broad-leaved forests. Collected seeds were mainly from the dominant species of the above-ground plant communities. However, the similarity in species composition between the seed rain and the above-ground plant communities was low. Seed rain showed a clear seasonal dynamic together with a large interannual and spatial variation, which reflected the typical characteristics of the seed rain in subtropical evergreen broad-leaved forests in terms of its spatial and temporal dynamics. This study provides data support for large-scale and long-term studies on seed ecology in evergreen broad-leaved forests. The spatial-temporal dynamics of the seed rain should be carefully referred to when collecting and sowing seeds during forest restoration processes.
Embryonic Callus Induction and Somatic Embryogenesis of Sophora davidii
Wu Lifang, Wei Xiaomei, Lu Weidong
2019, 55(7):  170-177.  doi:10.11707/j.1001-7488.20190719
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[Objective] The study is to explore the effect of different plant growth regulators on embryonic callus induction and the effect of nitrogen source and mineral concentration in MS medium on somatic embryogenesis and plant regeneration of Sophora davidii, and to establish a technical system of somatic embryogenesis,development and regulation, which would provide a basis for the establishment of rapid propagation system and genetic transformation of S. davidii.[Method] Leaves from S. davidii were used as explant to study the effects of growth regulators 2,4-D (1.0,2.0,3.0,4.0 mg·L-1), NAA (0,0.5,0.8,1.0 mg·L-1), 6-BA (0.2,0.5,1.0,2.0 mg·L-1) and TDZ (0,0.2,0.5,1.0 mg·L-1) on embryonic callus induction, and NAA (0,0.2,0.5 mg·L-1), 6-BA (0,0.5,1.0 mg·L-1)and TDZ (0,0.2,0.5 mg·L-1)on somatic embryogenesis, which aimed to screen optimum medium. Ratio of KNO3 and NH4NO3, mineral concentration (1/5MS, 1/4MS, 1/3MS, 1/2MS)in MS medium were tested to obtain a good culture condition for somatic embryogenesis and germination.[Result] The optimum medium for embryonic callus induction was MS + 2,4-D 3.0 mg·L-1+ NAA 0.5 mg·L-1 + 6-BA 0.2 mg·L-1 + TDZ 1.0 mg·L-1 + 40 g·L-1 sucrose + 7.0 g·L-1 agar,and the rate of embryonic callus induction reached to 42.0%. MS medium supplied with 0.5 mg·L-1 NAA, 1.0 mg·L-1 6-BA, 0.5 mg·L-1 TDZ, 40 g·L-1 sucrose, 100 mg·L-1 glutamine and 7.0 g·L-1 agar was suitable for somatic embryo formation, somatic embryogenesis rate was 78.46%, the number of somatic embryos was 3.6-fold compared with control. Improved MS supplied with 2-fold KNO3 and half NH4NO3 was beneficial to somatic embryogenesis, somatic embryogenesis rate was 91.33%, and the total number of embryos was 1.4-fold compared with the optimal basic medium. 1/3MS was beneficial to somatic embryo germination, and somatic embryo germination rate was 82.75%. Regenerated plantlets were developed well in 1/3MS medium, and mean fresh weight was 76 mg. Plantlets were successfully acclimatized with a survival rate of 90% and grew vigorously.[Conclusion] Different growth regulators,such as 2,4-D, NAA, 6-BA and TDZ combinations were helpful for inducting callus or embryonic callus, 2,4-D had a great influence on morphology and texture of callus. TDZ was helpful for the formation of somatic embryos. Proper auxin combination with cytokinin and proportion of nitrate and ammonium nitrogen can regulate the formation and development of somatic embryos. The rate of somatic embryo germination can be increased by reducing MS inorganic salt concentration. The survival rate of transplanted plantlets reached 90% in this experimental system.
Dynamics of Soil Microbial Biomass Carbon and Nitrogen in the Soil of Rhizosphere during Growing Season in the Cold Temperate Forests
Ding Lingzhi, Man Xiuling, Xiao Ruihan, Cai Tijiu
2019, 55(7):  178-186.  doi:10.11707/j.1001-7488.20190720
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[Objective] The rhizosphere plays an vital role for microbial-driven carbon and nitrogen sequestration and nutrient cycling of terrestrial ecosystems. Studies on dynamic of microbial biomass in rhizosphere soil can help us understand the mechanism of utilization and cycle of carbon and nitrogen, and also provide a scientific basis for forest protection and rational management in the study area.[Method] Taking the coniferous and broad-leaved mixed forest as the research object, the rhizosphere and non-rhizosphere soil samples were collected using shaking off method in the forests dominated by the main native tree species in the cold temperate forests of China (Pinus sylvestris var. mongolica, Larix gmelinii, Betula platyphylla and Populus davidiana). The enrichment, the differences and the variations during growing season of microbial biomass carbon and nitrogen in different rhizosphere soils were analyzed to explore the characteristics of soil microbial biomass and its contribution to soil nutrient pool.[Result] The changes of microbial biomass carbon and nitrogen in the rhizosphere soil of the different species were significant among different months. The microbial biomass carbon content in the rhizosphere soil ranged from 114.14 to 451.05 mg·kg-1,the microbial biomass nitrogen content in the rhizosphere soil ranged from 40.38 to 185.00 mg·kg-1. The enrichment rate of microbial biomass carbon in rhizosphere soil was in the order of Pinus sylvestris var. mongolica (87.99%) > Betula platyphylla (78.22%) > Larix gmelinii (73.14%) > Populus davidiana (56.96%). The rank of microbial biomass nitrogen enrichment rate was Populus davidiana (81.50%) > Betula platyphylla (77.63%) > Pinus sylvestris var. mongolica (76.42%) > Larix gmelinii (51.40%). The range of soil microbial biomass carbon-nitrogen ratio was 1.42 to 5.24. The ranges of microbial biomass carbon and nitrogen ratios in the rhizosphere and non-rhizosphere of Pinus sylvestris var. mongolica, Larix gmelinii, Betula platyphylla, and Populus davidiana were 1.42-5.24, 1.57-3.79, 1.67-4.55, 1.55-2.59 and 1.79-3.53, respectively. The average values of soil microbial biomass carbon-nitrogen ratio were 2.64, 2.63, 2.81, 2.11 and 2.36, respectively. The contributions of microbial biomass carbon to the rhizosphere soil organic carbon pool ranged from 0.83% to 0.95%.The contributions of microbial biomass nitrogen to the organic nitrogen pool of rhizosphere soil were between 3.63% and 5.08%.[Conclusion] The content of microbial biomass carbon and nitrogen in the rhizosphere soil of the main cold-temperate mixed forests were significantly higher than those in the non-rhizosphere during the growing season, which indicated that the rhizosphere effect wassignificant. At the end of the growing season, the rhizosphere effects of the coniferous trees were stronger than those of the broad-leaved trees. The conifer species have the greater impact on soil microbial structure and function than the broad-leaved trees.
Characteristics of Pollutants Released by Combustion of Chinese Fir Litterfall and PM2.5 Composition Analysis
Ju Yuanhua, Ma Xiangqing, Guo Linfei, Ma Yuanfan, Cai Qijun, Guo Futao
2019, 55(7):  187-196.  doi:10.11707/j.1001-7488.20190721
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[Objective] The objective of this study was to investigate the emission characteristics of gaseous and particulate pollutants from litterfall of Chinese fir plantation under different combustion states, and to extract and determine the chemical composition of PM2.5, in order to reveal the impact of forest fire and forest clearing on litterfall decomposition, nutrient cycling, and atmosphere environment.[Method] Four main components of leaves, branches, barks and stems of litterfall in Chinese fir plantation were selected as research materials. With a self-designed biomass simulation combustion system, an indoor simulation combustion experiment was conducted to analyze the characteristic variation of gaseous pollutants and PM2.5 released by different litter components under smoldering and flaming states. The carbonaceous components in PM2.5 were determined by an Elementar elemental analyzer (produced in Germany). The contents of water-soluble ions and water-soluble inorganic elements in PM2.5 were identified by ultrasonic extraction-ion chromatography and ICP/MS techniques.[Result] The result showed that the emission factors of CO2, CO, NOx, CxHy and PM2.5 varied in the range of 1 001.4-1 364.5,202.3-358.8, 0.53-3.09, 23.17-53.07 and 5.11-38.37 g·kg-1 in the smoldering state, respectively and varied in the range of 1 092.4-1 520.7, 115.1-242.6, 0.16-1.961,1.21-41.50, 2.58-21.07 g·kg-1 in the flaming state. In addition, the components of PM2.5 were extracted and determined. The result showed that PM2.5 contained carbonaceous components, water-soluble ions and a small amount of water-soluble inorganic elements. The content of carbonaceous components occupied the largest proportion, accounting for more than 50% of PM2.5. The average mass fractions of organic carbon (OC) and elemental carbon (EC) were 43.29% and 12.91% respectively. Six cations (Li+, Na+, K+, NH4+, Mg2+, and Ca2+) and five anions (F-, Cl-, NO2-, SO42- and NO3-) were identified in PM2.5, and the total water-soluble ions accounted for 10% -33% of PM2.5. Cl-, K+, Ca2+, and SO42- were determined as main water-soluble ions in smoldering state and K+, Cl-, SO42-, and Na+ were main water-soluble ions in flaming stage. Sixteen inorganic elements (K, Ca, Na, Mg, P, Zn, Al, Cu, As, Ba, Cr, Fe, Mn, Cd, Li and Pb) were extracted from PM2.5, but accounting for only 0.04%-0.58% of PM2.5, of which K, Ca, Na, Mg, P and Zn were the main elements, accounting for 96.8% to 98.8% of the total inorganic elements.[Conclusion] The same litterfall type under different combustion states showed significant differences in the emission factors of pollutants. Except CO2, the emissions of other pollutants in smoldering state were significantly higher than those in flaming state. In addition, there existed significant variation exists in the emission factors of CO, CO2, NOx, CxHy and PM2.5 from different components of litterfall of Chinese fir plantation at the same combustion state. PM2.5 was mainly composed of carbonaceous components, water-soluble ions and a small amount of inorganic elements and other ingredients. Generally, the concentration of each component in PM2.5 in the smoldering state was higher than that in the flaming state.
Prediction Model of the Spread Rate of Eight typical Surface Dead Fuel in Southern China under Windless and Flat Land
Man Ziyuan, Sun Long, Hu Haiqiang, Zhang Yunlin
2019, 55(7):  197-204.  doi:10.11707/j.1001-7488.20190722
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[Objective] The Rothermel model is the most widely used semi-physical prediction model at present. The aim of this study was to investigate the applicability of the Rothermel forest fire spread rate prediction model and the other two kinds of spread rate prediction models based on the Rothermel model to eight typical surface dead fine fuels in southern China to provide theoretical support and guidance for the forest fire spread rate prediction.[Method] Eight typical surface dead fine fuels in southern China were chosen as the research material, according to the actual conditions of the research material in the field, the fuel bed with different fuel moisture contents, fuel load and height was constructed in the wind tunnel laboratory of Maoer Mountain Experiment Forest Station of Northeast Forestry University. The 36 burning tests were carried out for each fuels under flat and windless condition, totaling 288 burning tests. The spread rate of each fuel type in different proportions was recorded. The most suitable prediction models for the forest fire spread rates of eight typical fuels in southern China were obtained by comparing the Rothermel model, re-estimating the Rothermel model parameters and the self-built model after improving the form of Rothermel model.[Result] 1) Under the flat and windless conditions, the maximum spread rate of eight typical fuels in southern China was 0.55 m·min-1. The average spread rate from big to small was as follows:Pinus armandi, Pinus yunnanensis, Phyllostachys edulis, Cryptomeria fortune, Cunninghamia lanceolate, Pinus massoniana, Quercus acutissima, Cyclobalanopsis glauca. 2) The Rothermel model was used to predict the spread rate of forest fire, the prediction error was large, the mean absolute error was 0.18 m·min-1, and the average relative error was 70.0%. 3) The prediction accuracy of re-estimating the Rothermel model parameters and self-built model was significantly higher than that of Rothermel model. The average absolute error of the re-estimating Rothermel model was 0.04 m·min-1, the average relative error was less than 18%; the average error of the self-built model was 0.037 m·min-1, the average relative error was 16.45%. 4) The prediction error was not significantly different between the re-estimating the Rothermel model parameters and the self-built models. The correlation coefficient between the predicted value and the measured value of the self-built model was 0.71-0.90, and the average value was 0.80.[Conclusion] For the eight typical surface dead fine fuel in southern China, the error of re-estimating the Rothemel model parameters and the self-built model was not significant, but the format of the self-built model was more simple and easy to use. The self-built model can be used to predict the surface fire spread rate of typical fuels in southern China.