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25 April 2016, Volume 52 Issue 4
Foliage Respiratory Characteristics of 5 Evergreen Tree Species Native to the Temperate Deciduous Evergreen Mixed Forest of North American
Li Ximeng, Li Zhengzhen, Liu Haiou, Shi Sha, Feng Jinchao
2016, 52(4):  1-10.  doi:10.11707/j.1001-7488.20160401
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[Obiective] This study aimd to investigate the interspecies variation in leaf respiratory characteristics and its underpinning factors, and quantify the impacts of such variation on the estimation of leaf carbon flux.[Method] Five evergreen species of Chamaecyparis thyoides, Pinus rigida, P. resinosa, P. strobes and Tsuga canadensis, which are common to temperate coniferous-broadleaf forest of Northern America, were chosen in this study. Leaf light photosynthetic response curves, and CO2 response curves and respiration temperature response curve as well as leaf morphological and biochemical traits were measured. Using linear regression, we analyzed the relationship among leaf respiratory characteristics, leaf structural, biochemical and physiological attributes. A coupled stomata-photosynthesis model was adopted to simulate the dynamic of leaf level carbon flux during the experimental period.[Result] Our results showed:(1) Interspecific difference was found in leaf area-based nitrogen content(Narea), but not in mass-based nitrogen content(Nmass). Likewise, there was obvious difference in the area-based respiration rate(Rnarea) was highly regulated by leaf morphological traits; 2) Leaf respiration rate could be well explained by its nitrogen content. Moreover, a positive relationship was also found among R, maximum net carbon assimilation rate(A) and specific leaf area(SLA); 3) Light inhibited leaf dark respiration in all species investigated, with the ratio of mitochondrial respiration under daylight to dark respiration rate(RL/Rn) spanning from 0.39 to 0.90. The RL/Rn ratio was positively correlated with maximum oxygenation rate(vo1500)and carboxylation rate(vc1500)of Rubisco. In addition, strong correlation was also found between leaf Rn and RL; 4) Q10 of dark respiration ranged from 1.44~2.24. Activation energy of respiration(E0) varied among species, but the variation was marginal; 5) With using fixed Q10 and assuming RL=Rn affected the estimation of leaf carbon flux was affected in all 5 species, but the extent and magnitude of influence were species-specific. The sum of carbon flux for the 5 species was only slightly affected.[Conclusion] In summary, those results clearly demonstrated that leaf respiratory characteristics were species-specific. Factors underlying the inter-specific variation include leaf nitrogen content and leaf morphological traits. The light inhibition of dark respiration was regulated by Rubisco carboxylation and oxygenation, reflecting that leaf photosynthesis and respiration were inter-related. Simulating leaf level carbon flux without considering the effects of Q10 and light inhibition of dark respiration would lead to incorrect outcomes in terms of leaf carbon gain. Apparently, such error will be undoubtedly magnified when scale up to canopy, ecosystem or global level.
Extracting Farmland Shelterbelt Automatically Based on ZY-3 Remote Sensing Images
Xing Zefeng, Li Ying, Deng Rongxin, Zhu Honglei, Fu Bolin
2016, 52(4):  11-20.  doi:10.11707/j.1001-7488.20160402
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[Objective] This paper was to explore a high precision automatic extraction method of farmland shelterbelt in northeast China based on analyzing its spectral and spatial geometric characteristics. And the results will provide basic data support for a wide range of farmland shelterbelt extraction and remote sensing monitoring.[Method] In this paper, part zones of Dehui City and Nong'an County of Jilin Province were took as the study area. We analyzed the vegetation index and spatial geometric features of the farmland shelterbelt based on ZY-3 multi-spectral image. The residential boundary was extracted from Landsat 8 OLI data. Then we put forward using the object-oriented method to deal with binary image data. The vector results of farmland shelterbelt were extracted in combination with the mathematical morphology and the GIS technology.[Result] The total length of farmland shelterbelt is 304.46 km within the 50 km×50 km study area. The correct extraction of farmland shelterbelt is 286.42 km, the excess extraction of 18.05 km and missing extraction is 14.19 km. In this study, we used the region verification, filed verification and high resolution images verification based on existing outcome data, filed observation data, GeoEye image and ZY-3 image. As for reqion verification, the extraction accuracy is 89.89%, the redundancy error is 5.66% and the missing error is 4.45%. All 22 belts collected in field were extracted correctly and the extraction accuracy of length is 93.93%.[Conclusion] The ratio vegetation index(RVI) is better than the normalized difference vegetation index(NDVI) when extracting the farmland shelterbelts in high vegetation coverage. Mathematical morphology method and object-oriented method have their unique advantages in processing linear characteristic features which has a certain gap, especially for the farmland shelterbelt. It should be given full consideration to the phenology information, spectral information and spatial geometry information of farmland shelterbelt when extracting farmland shelterbelt automatically with remote sensing technology. Accuracy verification results show that the combination of morphology, object-oriented methods and GIS technology to extract farmland shelterbelts can obtain higher accuracy based on ZY-3 image. This method can give a reference for extracting the farmland shelterbelt automatically and widely in northeast China. It also can provide technical support for the spatial analysis of landscape and the dynamic monitoring and management in the future.
Effects of Nitrogen Supply and Container Size on Seedling Growth, Root Characteristics, and Nutrient Status in Quercus variabilis Container Seedlings
Cheng Zhongqian, Li Guolei
2016, 52(4):  21-29.  doi:10.11707/j.1001-7488.20160403
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[Objective] Nitrogen(N) supply and container type have each proved to effectively regulate seedling quality. In this study, we tested if the combination of the two approaches couldimprove seedling quality and produce a superposition effect on seedling growthin order to provide a theoretical basis in the containerized seedling cultivation.[Method] Quercus variabilis, with a dominant taproot, was reared in two different depth containers(25 cm, 36 cm) with application of either deficient(25 mgN·seedling-1) or luxury(100 mgN·seedling-1) nitrogen supply, in a two factors completely randomize design. Seedling growth, root characteristics, and nutrient concentration were measured at the end of the growth season.[Result] N supply and container depth were significantly interacted on root N concentration, root volume, andsurface area for medium-class roots(2.0[Conclusion] Both the interactive and main effects of N supply and container depth indicated the necessity of combining the two approaches to improve seedling quality. The optimum combination of 100 mgN and 36 cm container was recommended for the container seedling production of this species with a dominant taproot.
The Mechanisms of Seed Dormancy of Wild Daphne giraldii and Methods for Dormancy Breaking
Yan Fang, Zhang Enhe, Wang Qinli, Mao Zhuhong
2016, 52(4):  30-37.  doi:10.11707/j.1001-7488.20160404
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[Objective] Wild shrub Daphne giraldii mainly grows on half-shaded half-sunlighted gentle slope with an altitude from 2 500 to 2 600 m of Qilian Mountains. In order to adapt to cold winter and cool summer in Qilian Mountains, the seeds of D. giraldii have developed a strong dormancy. This study was intended to explore methods of breaking the seed dormancy and improving germination rate of the D. giraldii seeds, therefore to provide theoretical basis and technical support to the propagation from seeds.[Method] Different seed treatments such as biological identification of germination inhibitors of D. giraldii seeds, immersing seeds in GA3 and 6-BA solution, low temperature sand stratification and dry storage were employed to study the types of and the causes for dormancy, and methods of breaking dormancy of D. giraldii seeds were investigated in this study.[Result] The results indicated that:1) The viability of newly collected D. giraldii seeds were 84.6%, but not germination at all, indicating that there was obvious dormancy phenomenon in freshly collected D. giraldii seeds. The process of water absorption, including quick soaking, stable soaking and saturated soaking stages, of D. giraldii seeds was in line with the Logistic curve, and the seed testa had no serious impact on water absorption of the seeds. 2) Alcohol extract and water extract of seed testa, endotesta and embryo had different degree of inhibitory activity on seed germination rate and radicle length of Chinese cabbage(Brassica pekinensis) seeds. The water extract of testa had more obvious inhibition effects than alcohol extract on the germination and the radicle length of Chinese cabbage seeds under the same condition. The alcohol and water extract of embryo completely inhibited the germination of Chinese cabbage seeds at the concentrations of 0.1 g·mL-1 and 0.15 g·mL-1, however the inhibitory effect of water extract of embryo were significantly lower than alcohol extract at the concentration of 0.05 g·mL-1, showing significantly inhibition in germination and radicle length. The alcohol extract of endotesta had extremely significant inhibition in germination and radicle length of Chinese cabbage seeds, but the water extract had less inhibition at all concentrations. These indicated that the main reason of the seed dormancy of D. giraldii might result from the joint effect of water-soluble germination inhibitory substances in seed testa, both water-soluble and alcohol-soluble germination inhibitory substances in embryo and alcohol-soluble germination inhibitory substances in endotesta. 3) The scanning by electron microscopic showed that the surface cells of the control seeds were smoother and the shape was more regular, the longer columnar cells constituted the palisade tissue, but some holes were found on the surface cells of the seeds after the low temperature sand stratification at 5℃ for 90 days, favorable for seeds to germinate. [Conclusion] Soaking seeds in GA3 and 6-BA solutions, low and warm temperature dry storage all could not obviously improve the germination of newly collected D. giraldii seeds, but sand stratification at 5℃ for 90 days could break seed dormancy effectively and the germination rate could reach about 80%. The dormancy of newly collected D. giraldii seeds is a type of comprehensive dormancy.
Main Fruit Characteristics of Ziziphus acidojujuba Germplasm Resources in Chaoyang, Western Liaoning Province
Liu Qingbai, Liu Mingguo, Xiao Deping, Ji Lianjun, Yang Yuling
2016, 52(4):  38-47.  doi:10.11707/j.1001-7488.20160405
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[Objective] Ziziphus acidojujuba C.Y. Cheng et M.J. Liu is one of the main ecological and economical tree species in Chaoyang region in western Liaoning Province, China. The diversity in fruit characteristics were studied to build a foundation for exploration and utilization of Z. acidojujuba resources.[Method] A total of 51 accessions of Z. acidojujuba were selected from the region under study, 21 main fruit characteristics were measured and correlation among characteristics, principal component analysis, cluster analysis, and probability grading were conducted.[Result] 1) There were abundant variations between these characteristics. The range of variation coefficient was from 7.69% to 84.36%, among them larger values were of proportion of double-kernelled accessions(84.36%), average mass of single fruit(68.25%), vertical length of fruit stone(66.94%), and the content of titratable acid(65.44%), respectively. All of the main characteristics displayed a normal distribution. 2) 21 pairs of characteristics were highly significantly correlated between each other, 16 pairs of characteristics were significantly correlated, such that the mass of single fruit displayed a highly significant positive correlation with the content of reducing sugar, significant positive correlation with edible rate, highly significant negative correlation with the content of titratable acid, and significant negative correlation with Vc content. 3) 8 principal components were drawn from the 21 main characteristics, the cumulative contribution rate was 81.581% from 1st to 8th principal component; The contribution of the major characteristics from large to small were in turn the vertical length of fruit stone, vertical length of fruit kernel, fruit cross diameter, single fruit mass, mass of 1 000 kernels, mass of single fruit stone, cross diameter of fruit kernel, cross diameter of fruit stone, fruit vertical length, content of reducing sugar, total sugar content, Vc content, and rate of double kernels. The 51 Z. acidojujuba accessions were clustered into 3 main categories according to the superiority. 4) Using probability grading method, 12 characteristics were graded by 5 levels, and 9 characteristics were graded by 3 levels.[Conclusion] The Z. acidojujuba fruit characteristics in the study area had a relatively large variation, and all of the 21 fruit characteristics displayed a normal distribution, there were significant or highly significant correlation between 37 pairs of characteristics. Based on the principal components analysis, the 51 Z. acidojujuba accessions were clustered into 3 main categories. The results would provide an important basis for breeding programs of Z. acidojujuba.
Genetic Diversity of Germplasm Resources of Melia azedarach Revealed by SRAP Markers
Liao Boyong, Wang Fang, Chen Lijun, Liu Mingqian, Ouyang Kunxi, Que Qingmin, Xi Wenkai, Li Pei, Chen Xiaoyang
2016, 52(4):  48-58.  doi:10.11707/j.1001-7488.20160406
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[Objective] This study was aimed to analyze genetic diversity of 31 provenances of Melia azedarach from 17 provinces in China by Sequence Related Amplified Polymorphism(SRAP) molecular markers, and to provide a basis for conservation of germplasm resources and breeding of M. azedarach. [Method] We obtained SRAP 1/0 matrix via SRAP molecular markers, calculated the parameters of SRAP molecular markers, and conducted analysis of molecular variance(AMOVA). Then we computed the genetic distance matrix of SRAP data, and carried out principal coordinate analysis(PCoA), Neighbour-Joining cluster analysis and Mantel's test for the correlation between genetic distance matrix and geographic distance matrix.[Result] 20 pairs of primer combinations, screened from 783 pairs of primer combinations, amplified 257 clear bands, of which 145 were polymorphic. The polymorphism information content(PIC) values ranged from 0.262 to 0.478, with an average value of 0.385. The screened 10 primer combinations with the highest PIC values could distinguish almost all of the populations, so that they could be used to identify provenances of M. azedarach rapidly. The results of analysis of molecular variance(AMOVA)indicated that 38.96% genetic variation is derived from among populations and 61.04% is derived from within populations. Mountain provenances GZ2 and GZ3 from Guizhou, YN1 and YN2 from Yunnan, HUN1, HUN2 and HUN3 from Hunan, SC2 from Sichuan, HEB from Hebei, and AH from Anhui displayed higher genetic diversity than other provenances did. The Neighbour-Joining cluster analysis and principal coordinates analysis displayed similar results, 31 M. azedarach provenances were clustered into east and west groups. Provenances of Cluster Ⅰ were distributed along the west of China, including provenances from Yunnan, Guizhou, Sichuan and Gansu, and cluster Ⅱ contained other 23 provenances that were distributed in the east of China. Within the cluster Ⅱ, SD1, HEB, SD2, SX, and GS provenances from north area were clustered into sub-group Ⅱ 1. The four southern provenances, HAN2, HAN1, GX2, and GD2, were clustered into sub-group Ⅱ 4. The rest provenances either neighbouring or close to each other were mostly clustered together. According to the Mantel test, there was a significant correlation between genetic distance and geographic distance(r=0.256, P=0.003).[Conclusion] SRAP markers can be accurately and effectively used in genetic diversity analysis of M. azedarach. More genetic variation of M. azedarach existed within provenances, while gene exchange among provenances was limited. The overall genetic diversity of the provenances was relatively low, while some mountain provenances had higher genetic diversity. On the basis of selecting provenances with high genetic diversity, breeding of M. azedarach should be focused on selection of families and individuals within provenance. Different provenances had their own obvious characteristics, and differences in geographical environment had a certain impact on their genetic diversity. The 31 provenances were clustered into the east and the west groups, and the east groups had several diversity centres, so it was suggested that the germplasm resources be conserved in multiple sites in situ respectively. The centre of the origin of genetic diversity of M. azedarach may have an ecological transition zone between the two different groups of provenances in China.
Diversity of Arbuscular Mycorrhizal Fungi in the Rhizosphere of Populus euphratica Seedlings in Ebinur Lake Basin, Xinjiang
Lü Jie, Lü Guanghui, Ma Yuan
2016, 52(4):  59-67.  doi:10.11707/j.1001-7488.20160407
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[Objective] In this paper, the diversity of arbuscular mycorrhizal fungi in the rhizosphere of Populus euphratica seeding in the Xinjiang Ebinur Lake National Nature Wetland Reserve was investigated by spore identification and molecular phylogeny, in order to explore AM fungi ecology function and the regulatory mechanisms to plant community structure in desert ecosystem.[Method] This study was conducted in the Xinjiang Ebinur Lake National Wetland Reserve, and the rhizosphere soil and root tissues of 7 P. euphratica seedlings were collected, respectively. The physical and chemical properties of the soil samples were determined, and the data were analyzed using SAS software. The wet sieving method was used to isolate the AM fungi spores from the rhizosphere soil of 7 P. euphratica seedlings and the spore pellet method was applied to identify the AM fungi species. Spore density and relative abundance were calculated, and AM fungi common structure and infection rate were observed. Meanwhile, the nested polymerase chain reaction was used to amplify rRNA gene fragments of AM fungi association with P. euphratica. Through sequence analysis and homology analysis, the rRNA gene fragments from AM fungi were identified and the reference sequences were obtained. Following, a phylogenetic tree was constructed with the new rRNA gene fragments and reference sequences by Mage software.[Result] The results showed that, Na+, Mg2+ and Ca2+ concentrations in the rhizosphere soils were significantly lower than in background soils, while the organic matter content of the rhizosphere soils was higher than that of the background, and the K+ concentration distributed evenly. In the rhizosphere soil samples, nitrogen, phosphorus and sulfur contents were highly positively correlated with the organic matter content, while the contents of K+, Ca2+ and Na+ were highly negatively correlated with the organic matter content. Eight species belonging to 3 AM fungal genera were isolated and identified in the rhizosphere soil of 7 P. euphratica. In these species, G. dominikii, G. viscosum, G. reticulatum, G. melanosporum belonged to Glomus, A. morrowae, A. excavata, A.undulata to Acaulospora, and Scu. erythropa to Scutellospora. In addition, 13 new AM fungal taxa association with P. euphratica were identified and the Genbank accession number are KJ209699-KJ209711. After the analysis of Blast homologous alignment and phylogenetic relationship, the AM fungal taxa in P. euphratica were divided into two groups with less than 93% similarity, and the taxon of two AM fungal groups belong to different species of the genus Rhizophagus.[Conclusion] The P. euphratica with AM fungi can significantly reduce salt concentrations in the rhizosphere soil, and simultaneously increase the organic matter content, as well as the contents of nitrogen, phosphorus and sulfur. In this study, 13 new AM fungal taxa association with P. euphratica were separated into two groups belonging to one genus. From this result, in the flora with P. euphratica as the constructive species, the AM fungi associated with constructive species have the host selectivity to avoid nutrition competition to each other, and hence regulate the structure of the plant community in flora.
Correlations between Supercritical Extracts of Coniferous Fuel and the Heat Yield Value and Ignition Point
Zhao Fengjun, Wang Qiuhua, Shu Lifu, Yang Lijun, Liu Kezhen
2016, 52(4):  68-74.  doi:10.11707/j.1001-7488.20160408
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[Objective] Extracts, a very important component of fuel, can be divided into two categories:fatty acid extracts and volatile oil extracts. Traditional extraction methods have many shortcomings, including complicated operations, long procedure times, and low efficiency. To explore a simple, and fast technique for fuel extraction, the correlations between supercritical extracts of coniferous fuel, which were found on Daxing'anling Mountain, and their heat yield value and ignition point were studied.[Method] Fuel samples were collected from six conifer species, including Larix gmelinii, Pinus sylvestris var.mongolica, Picea jezoensis, Picea koraiensis, Pinus pumila, Sabina davurica. Samples of each tree species were divided into two categories:needles and twigs. After air drying, the samples were ground. By comparing extracts from different samples, the supercritical CO2 extraction conditions were optimized. The heat yield values of the samples were determined using a PARR 6300 automatic oxygen bomb calorimeter. The ignition points of the samples were determined by a DW-2 ignition temperature sensor.[Result] A correlation analysis showed that the heat yield values were closely correlated to the extract contents. However, there was no obvious correlation between the extract contents and the ignition point. Based on the correlation results, it can be inferred that the extracts in the experiment were mainly fatty acids.[Conclusion] The supercritical fluid extraction conditions were established in the present study, i.e., samples size 40 mesh, extraction temperature 45℃, extraction pressure 40 MPa, static extraction time 10 min, collection time 2 h, flow rate 2.0 L·min-1 and is the suitable conditions for fatty acids extracts of forest fuels. Under these conditions, the needle extract contents were closely related to the heat yield values, as indicated by the high correlation coefficient(0.972 2). With the present methods, the fatty acid extracts contents of fuels can be determined quickly. Compared with the traditional Soxhlet extraction method, the present method has many advantages, including its simple operation, short procedure time, and high extraction efficiency.
Optimization of Culture Conditions to Produce MnP and Dye Decolorization of TN02A7-He-mnp1 and TN02A7-He-mnp2
Sun Shina, Chi Yujie, Yu Cun, Li Yue
2016, 52(4):  75-82.  doi:10.11707/j.1001-7488.20160409
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[Objective] The initialized culture conditions for two Aspergillus nidulans tranformant stains TN02A7-He-mnp1 and TN02A7-He-mnp2 to produce manganese preoxidase(MnP)were optimized so as to enhance MnP activity and yield significantly. The decolorizing capacity of optimized culture solutions of two stains to 3 kinds of dyes was determined.[Method] Single-factor test was conducted to screen the optimal temperature for two strains to produce MnP. An orthogonal test was conducted to determine the effects of four factors- hemin concentration, Mn2+ concentration, pH value, and rotation speed on MnP activity, and a confirmation test was conducted to measure MnP activity. The absorbance value was determined to evaluate the decolorizing capacity of optimized culture solutions to 3 kinds of dyes.[Result] Results showed that the most optimal culture parameters for TN02A7-He-mnp1 to produce MnP were Mn2+ 267 μmol·L-1, hemin 0.05 g·L-1, 2 tablets of φ=10 mm inoculum, 50 mL culture solution of pH=7.5 in 100 mL flask at 180 r·min-1 shaking condition, and under culture temperature of 37℃, on the basis of MMPGRT liquid medium plus to 2 g wood chip of Populus ussuriensis as substrate. The most optimal culture parameters for TN02A7-He-mnp2 to produce MnP were similar to those of TN02A7-He-mnp1, but only hemin 0.03 g·L-1 and at 220 r·min-1 shaking condition. Under above-mentioned optimal culture conditions, the highest MnP activity reached 133.62 and 147.09 U·L-1 after 120 h culture for TN02A7-He-mnp1 and TN02A7-He-mnp2, respectively, which was 2.89 and 3.46 times higher than that produced at initial conditions. Decolorization tests showed that decolorization percents of two strains to heterocyclic dye neutral red and azo dye congo red surpassed 58% at 4 h, as high as or nearly to 100% at 16 h to neutral red and 20 h to congo red, respectively.[Conclusion] The MnP yield produced by two A. nidulans tranformants could be enhanced under optimal medium composition and culture conditions, and optimized extracellular MnP solutions of two strains could effectively decolorize heterocyclic dye neutral red and azo dye congo red.
Analysis on the Effects of Key State-Owned Forestry Reform on Employment
Wang Hui, Zhang Haipeng, Xu Jintao
2016, 52(4):  83-90.  doi:10.11707/j.1001-7488.20160410
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[Objective] Based on the micro survey data of key state-owned forestry area, this paper analyzed the impacts of state-owned forestry region reform on the changes in employment, which would provide a useful reference for the policy of key state-owned forestry region.[Method] We described the changes of industries, departments and aspects of employment in state-owned forestry region by statistical methods. Furthermore, we applie an econometric model to estimate the effect of state-owned forestry reforms on the employments.[Result] The reforms have already produced significant effect on employment in key state-owned forestry region. The dependence of labors on the state and forestry departments have gradually decreased. The field of employment has been widened. The responsibility system in forestry management and protection promoted an increasing employment rate in state and forestry departments by separating ownership from managerial authority. Market-oriented forestry production has played a positive role in promoting the forestry employment. Restructuring of processing enterprises has promoted the labor force from the state departments to the non-state departments. Buying out the length of services has promoted the labor force flowing to non-forestry industry, and extended the field of employment.[Conclusion] The structure of employment has changed in key state-owned forest region, and a new labor market has been formed. The role of market in the employment will be an important direction for system reform in the future.
Advances in Studies of Forest Gap Ecology
Guan Yunyun, Fei Fei, Guan Qingwei, Chen Bin
2016, 52(4):  91-99.  doi:10.11707/j.1001-7488.20160411
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Forest gap, though an interference at local scale, is an important driving force forest reqeneration nutrient cycling and ecosystem functioning of forests. By thoroughly reviewing the literature of forest gap studies, this paper was intended to advance the knowledge for both scientific research and forest management. Traditionally, forest gap ecology focuses on the formation and characteristics of gaps, and the consequent impacts on above-ground ecological processes(e.g. microclimate and plant community characteristics). Nowadays, a growing body of the research shifts sights to the effects of forest gap on under ground ecological processes(e.g. fine roots and litter decomposition, soil carbon and nitrogen dynamics, soil enzyme activities) and ecophysiological traits of animals and soil microorganism. However, current knowledge of these new spots is limited by the small spatial and temporal research scales. With the purposes of improving stand structures, ecological services function and process of forests, future work should focus more on the effects of forest gap on under ground ecological processes(e.g. fine roots decomposition and rhizosphere effect, distribution, cycling and immobilization of soil carbon and nitrogen) and ecophysiological traits of organisms. Furthermore, future studies should enlarge their research scales, and should also integrate above- and under ground ecological ecosystem, biotic and abiotic factors, as well as micro- and macro-scales.
Interaction of Litter Decomposition and Fine-Root Growth
Wang Wei, Hu Kai, Dang Chengqiang, Tao Jianping
2016, 52(4):  100-109.  doi:10.11707/j.1001-7488.20160412
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In different forest ecosystems, fine roots commonly proliferate into litter layers, especially into those with favorable conditions for root growth. Our aim is to provide a basis for better understanding the role and mechanism of action in litter decomposition by fine roots and the influence of litter decomposition on fine root growth.We reviewed the advances of recent studies, including how roots forage into litter, the factors influencing this foraging, and the influence and possible mechanisms of fine root growth on litter decomposition. We put forward a conceptual module that enhances understanding of the interaction between fine-root growth and litter decomposition.Litter quantity on the soil surface affects the foraging behavior of fine-roots and drives their growth dynamics. Litter quality can also affect fine-root growth. Fine-root growth enhancement or inhibition could be the result of a positive or negative balance between nutrient and polyphenols concentrations generated during the decomposition of litter with different properties. By proliferating in litter, fine roots potentially influence litter decomposition through priming effects, N uptake, and symbiotic mycorrhizal fungi. The priming effects of live fine-roots on litter decomposition are mainly manifested by root exudate C inputs, which can regulate decomposition of litter by controlling the activity and composition of the microbial community. Nitrogen availability is critically important to litter decomposition, and low N availability can increase decomposition as microbes use labile substrates to acquire N from recalcitrant organic matter. Fine-roots grow into a decomposed litter layer, which avoid the adverse effects of excess N on microorganisms by absorbing a large amount of inorganic N during litter mineralization. In addition, root symbiotic partners, i.e., mycorrhizal fungi, have an important impact on litter decomposition through the types of fungi and enzymes and organic acids secretion.Key scientific issues for future research include the mechanism of combined effect of fine root growth on litter decomposition in the context of global climate change, as well as the connection of the fine root branching structure and function of nutrient acquisition in the litter layer.
Revision of Scientific Nosmes for the main Insect Species in the Monograph "Forest Insects of China(2rd Edition, 1992)"
Ren Lili, Li Zhenyu, Li Yingchao, Guo Yimei
2016, 52(4):  110-115.  doi:10.11707/j.1001-7488.20160413
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[Objective] Scientific name of an insect is the unique international name for each species. The monograph "Forest Insects of China (2nd edition)" was published in 1992, and since then large numbers of scientific names have been changed, resulting in inconvenience in academic communication. The 3rd edition of the monograph will be revised and published soon; and it will be published in both Chinese and English versions. The accuracy of both Chinese name and the scientific name of the species containing in this edition is important.[Method] During the process we revised the insect scientific names in the 2nd edition by referring to the monographs such as "Fauna Sinica", new entomological taxonomy studies and journals such as "Acta Entomologica Sinica" et al.[Result] Scientific names of three species of pine caterpillars in China have been changed into Dendrolimus grisea (Moore), D. punctata punctata (Walker), D. kikuchii kikuchii Matsumura. The taxonomic status of one important locust damaging bamboos has been moved into another genus, and its scientific name right now is Rammeacris kiangsu (Tsai), and the Chinese name has been changed accordingly; Species name of Apriona germari (Hope) is also changed; Three species were only identified to genus and did not given exact species name previously, and now they are identified to species, and are named as Celypha sp. Liu damaging Pseudolarix amabilis (Nelson) Rehd., and two psyllids attacking Populus euphratica Schrenk and P. heterophylla Linnaeus. Matsucoccus matsumurae (Kuwana), M. massonianae Yang et Hu and M. liaoningensis Tang have been found to be the same species:M. matsumurae (Kuwana); Scientific names of species in the families of Tortricidae and Lasiocampidae, in the suborder "Rhopalocera", as well as in the order Isoptera have been changed a lot. We referred many monographs, e.g. "Fauna Sinica, Insecta, Vol. 27, Lepidoptera Tortricidae", "Fauna Sinica, Insecta, Vol. 47, Lepidoptera Lasiocampidae", "Monographia Rhopalocerorum Sinensium", "Fauna Sinica, Insecta, Vol. 17 Isoptera" et al. and gave correct names for those species in the families.[Conclusion] The Chinese names and scientific names of some species in the 2nd edition of "Forest Insects of China" would be corrected with the edition and publication of the 3rd edition, providing essential information for scientific researches and communication of forest insects.
A Review of Pure Viscoelastic Creep and Mechano-Sorptive Creep of Wood
Peng Hui, Jiang Jiali, Zhan Tianyi, Lü Jianxiong
2016, 52(4):  116-126.  doi:10.11707/j.1001-7488.20160414
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Wood, as one kind of fibre-composed material, consists of various cell types. The layer structure of cell wall and the chemical compositions of cell are diversity. Under constant stress, the deformation degree of wood increases with increasing time, i.e., wood creep. Wood creep plays an important role in the quality of wood products and engineering components, which is also the main design parameter for wood structures. According to the state of moisture, creep phenomenon could be divided into "pure viscoelastic creep"[under constant moisture content(MC) conditions] and "mechano-sorptive(MS) creep"(under varied MC conditions). This paper reviewed the phenomena and characteristics of pure viscoelastic creep and MS creep, respectively. For pure viscoelastic creep, the emphases were on the effects of anatomy structure, moisture content, temperature and stress level as well. For MS creep, the emphases were on microfibril angle, chemical composition, moisture content as well as temperature. In addition, the main mechanisms of MS creep were interpreted from the perspectives of molecular level, cell wall layer structure and physical ageing, etc. Stress-strain constitutive equation and Kelvin-Voigt model were also summarized in this paper. Additlonally, the numerical simulation of pure viscoelastic creep and MS creep were introduced, respectively. Wood creep mainly depends on anatomy structure and ambient conditions, and even the interactions among these factors, which lead to tremendous space for improvement. In the future, our main work should focus on the following four topics:1) Depending on orthotropy properties of wood to characterize orthotropic creep behavior combined with loading directions and deformation modes. 2) To clarify the effect mechanism of moisture, temperature and their interactions on chemical component. Moreover, the combined technology of real-time measurements on creep compliance and Poisson's ratio should also be conducted. 3) Creep behavior of single wood fiber under cyclic humidity is essential to investigation, which is helpful to illuminate the roles of hemicellulose on MS creep, and the hydrogen bonding effect mechanism at molecular level. 4) To establish models to demonstrate the mechanism of pure viscoelastic or MS creep in wood.
A Method for Measuring Nitrogen Chemical Properties of Tree Stem-Flow with UV Spectrophotometer
Yang Lin, Wang Chuanhua, Li Tao, Wang Li, Guo Yidong
2016, 52(4):  133-141.  doi:10.11707/j.1001-7488.20160416
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[Objective] In studies of nitrogen cycling of forest system, it is important to determine nitrate nitrogen, nitrite nitrogen, ammonia nitrogen and total nitrogen of tree stem-flow accurately, the aim of this paper was to develop a method to measure the contents of these chemical properties with UV spectrophotometer.[Method] Stem flow of 8 canopy tree species from Shenlongjia Mountain were selected to measure nitrate nitrogen (F) content in the stem-flow using 4 common methods, including UV spectrophotometry, nitrate electrode, phenol disulfonic acid and thymol, and to decide which method was the best for detecting nitrate nitrogen (F) content; the stem-flow was oxidize at 125℃ for 45 minutes by using refined potassium persulfate solution and total nitrogen (T) was then detected using UV spectrophotometer and nitrate cathode respectively. The stemflow was oxidized with potassium permanganate solution and the total content of nitrate and nitrite (B) was s then measured with UV spectrophotometer. The content of nitrite was calculated as B-F, and ammonia as T-B, then the content of ammonia was compared with that detected by the method of Nessler's reagent.[Results] The UV spectrophotometry was the best method among the 4 methods in detecting nitrate nitrogen, with an accuracy and a precision of 106.19%±8.26% and 3.0%, respectively; the accuracy and precision of nitrate cathode, thymol and phenoldisulfonic acid were 102.5%±12.08% and 2.0%, 107.44%±9.26% and 4%, 43.62%±26.39% and 12%, respectively. The accuracy and precision of total nitrogen (T) measured with UV spectrophotometry were 94.62%±2.19% and 2.0%; In contrast, the accuracy of nitrate electrode method was 98.93%±37.64%%, indicating that it was not applicable to some tree species. Accuracy and precision of nitrate and nitrite(B) measured with UV spectrophotometry were 100.97%±2.85% and 4.0%, indicating that it was perfect in detecting nitrate and nitrite. The precision of ammonia and nitrite calculated from T, F and B were up to 3.0% and 4.0% respectively, suggesting that our method was suited for detecting ammonia and nitrite.[Conclusion] Tree stemflow could be oxidized with potassium persulfate and potassium permanganate, then nitrate nitrogen (F), total nitrogen (T) and total content of nitrite and nitrate all can be measured directly with UV spectrophotometer, and nitrite and ammonia of stemflow could be calculated with them.
Physiological differences in Dormancy of Different Cold Hardiness Hazelnut Hybrid
Lü Yuedong, Wang Guixi, Duan Wenbiao
2016, 52(4):  142-146.  doi:10.11707/j.1001-7488.20160417
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[Objective] Respiration intensity is closely related to cold resistance of plants, and temperature is an important factor affecting respiration.On the basis of preliminary identification of the cold resistance, this study explored changing trends of relevant physiological indexes during dormancy of different cold-resistant hazel hybrids, and physiological mechanisms to adapt to the low-temperature environment, to provide abasis forfurther studyingcold resistance of hybrid hazels.[Method] The phenology of three clones (84-349, 84-237 and 84-572) with different coldresistance, which were selected in our previous experiments, were observed.We measured respiration rate, branches electrolyte leakage, and soluble protein content and soluble sugarscontentsof shoots of the three clones during dormancy, to explore the relationship between dormancy and cold resistance.[Result] The strong cold resistance clone, 84-349, was the earliest to enter the dormant period and the latest to bloom;There were no differences in physiological indexes during the deep dormancy over the three clones. However, in the early stage and late stage of dormancy, the clone of 84-349 had the lowest respiration rate, the least electrolyte leakageand the highest soluble sugar and soluble protein contents.Whereas the weak cold resistance clone, 84-572, was opposite, with thehighest electrolyte leakage, highest respiration, and the lowest soluble sugar and soluble protein contentsamong the three clones.[Conclusion] Three hybrid hazelnut clones with different cold resistance had different physiological performancesin dormancy.Compared with the weak cold resistance clones, thestrong cold resistancecloneresisted low temperatureby early entering dormancy, reducing respiration rate, lowering the electrolyte leakage and increasing storage ofenergy matter indormancy.
A New Variety of Zelkova schneideriana ‘HenTianGao’
Jin Xiaoling, Wang Xiaoli, Liu Xuemei, Hu Xijun, Liao Fei
2016, 52(4):  147-147.  doi:10.11707/j.1001-7488.20160418
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HenTianGao' is a new variety of Zelkova schneideriana, was selected and bred from the seedling mutant. The variety has many characteristics of slow height growth rate, low branch point, many branches late autumn leaf color change and late leaf falling. The experimental result showed that the variety has stable character, as well as good adaptability and strong resistance. It has high survival rate in grafting propagation. It can be applied in the landscape greening, especially in roof greening.
An Elite Variety of Euonymus japonicus ‘Huayuanfa’
Yao Yanwu, Li Yongli, Liu Guobin, Cao Jun
2016, 52(4):  148-148.  doi:10.11707/j.1001-7488.20160418
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Euonymus japonicas ‘Huayuanfa’ is a new variety of ornamental tree species, with strong cold resistance. The variety was selected from an asexual breeding population. ‘Huayuanfa’ is small evergreen tree. The leaf color is dark green on blade adaxially and light green on blade abaxially in spring and summer, and is green in winter without defoliation. Fruits appear bright red when cracking, then the trees are very beautiful with red fruits and green leaves. This variety is suitable for landscaping in northern China.