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Wang H.,Chinese Academy of Forestry | Wan P.,Chinese Academy of Forestry | Wang Q.,Chinese Academy of Forestry | Liu L.,Chinese Academy of Forestry | And 3 more authors.
Forests | Year: 2017

Inter-tree competition is considered one of the most important ecological processes of forest development. However, its importance in structuring the spatial patterns of plant communities remains controversial. We collected observational data from two plots in a natural Mongolian Scots pine forest to study the contribution of competition to tree growth, mortality, and size inequality. We used the nearest neighbour method to determine the presence of competition, and unmarked and marked spatial point pattern analyses to test the density-dependent mortality effects and the spatial autocorrelation of tree size. We identified significant positive correlations between tree canopy diameter and nearest neighbour distance in both plots, which were more evident in the denser plot. The pair correlation functions of both plots indicated regular distribution patterns of living trees, and trees living in more crowded environments were more likely to die. However, the mark differentiation characteristics showed weak evidence of a negative spatial autocorrelation in tree size, particularly in the high-density plot. The high mortality rate of suppressed trees and weak asymmetric competition may have accounted for the lack of dissimilarity in tree size. This study showed that inter-tree competition is an important determinant of the development of Mongolian Scots pine forests. © 2017 by the authors.

Qiu K.,Beijing Forestry University | Jia B.,Chinese Academy of Forestry | Jia B.,Key Laboratory of Tree Breeding and Cultivation | Zhang Z.,Beijing Forestry University
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2015

Evaporative fraction (EF) is an important parameter to estimate evapotranspiration (ET) for regional ecosystem, and also an indicator to evaluate the moisture status of the terrestrial ecosystem. Based on the climate data in China and moderate-resolution imaging spectroradiometer (MODIS) products such as MOD11B3, MOD13A3 and MOD12, this manuscript focused on the monthly mean EF estimation using the Priestley-Taylor model and EF validation using the ground-based eddy measurement data, analyzed the spatio-temporal patterns of monthly mean EF and evaluated its responses to the climate factors in the vegetated region in China, in order to obtain the seasonal change characteristics of EF and its sensitivity to climate. Results showed that monthly mean EF dynamics in the vegetation ecosystems had significant seasonal change characteristics. During the whole year, vegetation ecosystem in South China had a higher value than those in other regions in China. In spring, monthly mean EF increased in the south of Yangtze River and Sichuan Basin. And then the regions with high EF value expanded to the North China Plain and the Northeast China in summer. In autumn, the regions with high EF value shrank, and the distribution of monthly mean EF was similar to that in spring. The correlations between the spatial distribution of EF and climate factors showed seasonal variability. In spring and autumn, the EF was significantly correlated (P<0.01) with monthly total solar radiation, monthly mean temperature and monthly precipitation. In winter, monthly mean temperature was the sole factor significantly affecting (P<0.01) the EF in vegetation ecosystem in China. Contrary to these, there were no significant correlations between EF and climate factors in summer. The reason was the distinguishing relationships between monthly mean EF and climatic factors. Regional variability was also found in the sensitivity of seasonal EF to the climate. The higher sensitivity to monthly precipitation was found in the northern and inland regions compared to that in the southern and coastal regions. On the contrary, vegetation ecosystem in the southern and coastal regions showed higher sensitivity to monthly mean temperature and monthly solar radiation. This was accordant with the differences of the moisture conditions between northern and southern ecosystems. In Southwest China, the negative relationship between monthly mean EF and monthly mean temperature showed the drought in the hot season was controlled by the southwest monsoon in this region. On the Qinghai-Tibet Plateau, the sensitivity of monthly mean EF to climate was lower than that in other regions. Monthly mean EF of deciduous broadleaf forest, shrub land and grassland had high seasonal variability, while the seasonal variability on monthly mean EF of evergreen broadleaf forest was relatively insignificant. The relationships between EF and climatic factors for each vegetation type showed that monthly mean EF of cropland was more highly related to monthly precipitation, monthly mean temperature and monthly solar radiation than those of other vegetation types. Compared to cropland, monthly mean EF of forest showed less sensitivity to monthly precipitation. Among various forest types, monthly mean EF of mixed forest and evergreen broadleaf forest had the highest sensitivity to monthly solar radiation, followed by deciduous broadleaf forest, deciduous conifer forest and evergreen conifer forest, suggesting that the broadleaf forest had higher sensitivity to monthly solar radiation. Similar to the sensitivity to monthly solar radiation, monthly mean EF of broadleaf forest had a higher sensitivity to monthly mean temperature than that of conifer forest. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.

Qiu K.,Beijing Forestry University | Cheng J.,Shaanxi Qianweizhihui National Wetland Park Management Office | Jia B.,Chinese Academy of Forestry | Jia B.,Key Laboratory of Tree Breeding and Cultivation
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2015

Water use efficiency (WUE) of vegetation is an important parameter coupling the carbon cycle with water flux in the terrestrial ecosystem, as far as to the whole earth. Under the background of climate change, WUE is likely sensitive to the climatic factors. But for cropland, cultivation, as well as the climate change, also exerts great influences on the long-term WUE. However, questions are still remained about the spatio-temporal distribution of WUE and its affecting factors, for example what factors significantly affect the cropland WUE inter-annual variations and whether the effects of these factors vary with different regions at regional scale. Therefore, in order to obtain the change characteristics of WUE and the influential factors, this study focused on the application of data from moderate-resolution imaging spectroradiometer (MODIS), estimated the cropland WUE, analyzed the spatio-temporal patterns and evaluated the effects of climate change and two kinds of cultivation, irrigation and fertilization in the cropland in the middle of east of China. The cropland multiyear averaged WUE and its dynamics were evaluated in five regions that were delineated according to the dynamics of crop planting structure including: Region I representing the area where the crop was dominated by wheat and corn with rapidly expanding maize planting area, Region II where the crop was dominated by wheat and corn with expanding planting area, Region III where the crop was dominated by wheat and rice with expanding planting, Region IV where the crop was dominated by rice with expanding rice planting area and Region V dominated by rice with shrinking rice planting area. Results showed that multiyear averaged WUE was the largest in the North China Plain, Shandong Peninsula and the coast region in Jiangsu, with an average value of 2.0 g/kg, while in the Northeast China Plain and Hilly Region of Southeastern, the multiyear averaged WUE was approximately below 1.5 g/kg. Generally, multiyear averaged WUE was higher in the northern dryland field rather than in the southern paddy field. During the period from 2003 to 2012, the cropland WUE had an increasing trend in the middle and east of China. Compared to the southern paddy field, the northern dryland field had a larger rise. The largest increasing trend was found in the North China Plain where the cropland WUE increased by 0.02 g/kg per year. The cropland WUE showed a decreasing trend in the Hilly Regions of Southeast, area between Yangtze River and Huaihe River and Sanjiang plain with the largest decreasing amplitude approximately -0.007 g/kg per year. Generally, the increasing trend was more prevalent in the northern dryland field rather than in the southern paddy field. Correlation analysis showed that precipitation, effective irrigated area and fertilization were significantly (P<0.05) correlated with WUE inter-annual variation in Region II, solar radiation and precipitation in Region III and annual average temperature in Region IV. For Region II, due to the high co-linearity between precipitation with effective irrigated area and fertilization, the effects of irrigation and fertilization seem to be negligible for the inter-annual variation of cropland WUE. In the northern dryland field, precipitation was the main factor, while precipitation and annual average temperature were the main factors in the southern paddy field. In the northern dryland field, precipitation significantly controlled cropland evapotranspiration, while in the southern paddy field, the gross primary productivity was strongly regulated by annual average temperature. It is indicated that the different effects of climate on cropland WUE in the middle and east part of China, which will be of great importance on the rational utilization of water resource and the sustainable development of ecological environment in cropland. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.

Jia B.,Chines Academy of forestry | Jia B.,Key Laboratory of Tree Breeding and Cultivation
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2013

The normalized difference vegetation index (NVDI), linearly correlated with density distribution of vegetation, is widely used for investigating macro-scale vegetation coverage and thus vegetation changes at short and long time scales. We calculated the vegetation coverage and NDVI greater than 0. 1 by the Landsat TM satellite images on Sept. 26, 1987 and Sept. 22, 2009 for Beijing, China. The driving forces for vegetation changes were also analyzed including climate, geomorphology, human activities. In addition, the buffer analysis tool in the ARCGIS was used to derive the vegetation changes along the rivers as well as around the reservoirs and lakes. The quantitative analysis indicated that the land area of extremely low coverage, medium coverage and high coverage decreased by 5. 15%, 0. 54% and 0. 03% respectively, while the area of vegetation of low coverage and extremely high coverage increased by 5. 71% and 0. 01%, respectively from 1987 to 2009 for the whole region of Beijing. The statistical results in NDVI greater than 0. 1 showed that the vegetation quality of the whole city had basically improved and improved area reached 919302. 3 ha. The ratio of slightly, moderately and extremely improved area was 28. 31%, 41. 33% and 30. 36%, respectively. In addition, the degraded area was identified as 326931. 12 ha. Considering NDVIs for different sub-regions of the city, the most noticeable vegetation degradation took place within the 5th ring and between the 5th ring and the 6th ring and the percentage of the area of degraded vegetation was 58. 17% and 47. 38%, respectively for these two 2 regions. Contrarily, the regions with minimum percentage of vegetation degradation included Taihang Mountain and Yanqing Basin and the vegetation degradation area was 13. 35% and 17. 02%, respectively. Furthermore, the degradation for the Taihang Mountain and Yangqing Basin was basically attributable to slightly moderate degradation. There was no significant correlation between vegetation changes and climate changes both for whole Beijing and its sub-regions. However, human activities were found to be the major driving forces for vegetation changes in Beijing including regional green ecological restoration projects for both mountains and plains), urban landscape and greening projects, agricultural structure amendment for plain regions, and eco-environment restoration efforts for rural regions. In addition, water bodies had a very important effect on the vegetation changes along the river and around the reservoirs and lakes. A massive construction of reservoirs in the mountain region resulted in the no flow phenomena for the rivers in plain regions, thus, water body effects on the vegetation occurred in the mountain area. NDVI and vegetation coverage changes were buffered by 0-50m, 50-100m, 100-150m, 150-200m and 200-250m. We found that the buffer distance can be divided into two spatial levels for NDVI calculation. NDVIs buffered by 0-100m were enhanced over 0. 1, but the NDVIs buffered by 100-250m increased by 0. 0084-0. 0089 from 1987 to 2009. We also found that the 0-250m buffer ranges also can be divided into two levels for vegetation coverage analysis. Compared with 1987, the ratio of vegetation coverage in 2009 was reduced for the buffer of 0-200m and increased for the buffer of 200-250m. Therefore, the changes of river water body caused by precipitation can influence riparian vegetation within 150 m from the average water level, especially within 100 m.

Zang L.,Northeast Forestry University | Zang L.,Chinese Academy of Forestry | Zheng T.,Northeast Forestry University | Su X.,Chinese Academy of Forestry | Su X.,Key Laboratory of Tree Breeding and Cultivation
Plant OMICS | Year: 2015

Fasciclin-like arabinogalactan proteins (FLAs) family, belonging to a subclass of arabinogalactan proteins (AGPs), contains AGP-like glycosylated domains and fasciclin-like domains. FLAs are widely distributed in various plants and are involved in plant growth and development. In this paper, recent advances in the structure, expression pattern, biological function and application prospect of plant FLAs are summarized.

Yang H.,Chinese Academy of Forestry | Yang H.,Nanjing Agricultural University | Koide R.T.,Brigham Young University | Zhang Q.,Chinese Academy of Forestry | Zhang Q.,Key Laboratory of Tree Breeding and Cultivation
Plant and Soil | Year: 2016

Aims: Our aim was to investigate the effects of short-term waterlogging in shaping communities of the obligately aerobic AMF in roots of Populus deltoides.Methods: AMF community in populus roots was deciphered with 454-pyrosequencing method from a field plot before and after 15 days waterlogging. Results: We found that short-term waterlogging significantly altered the AMF community as confirmed with NMDS. Indicator species analysis identified 12 AMF OTUs that shown with different relative abundance between before and after waterlogging. In contrast to expectation, short-term waterlogging increased detectable AMF species richness: 4 OTUs were detected only before and 17 only after waterlogging. Conclusions: Variation in abundance of dominant OTUs was possibly due to short-term waterlogging disturbance and the role of competitive release in the increase in species richness following waterlogging. © 2016 Springer International Publishing Switzerland

Liu J.,Chinese Academy of Forestry | Liu J.,Key Laboratory of Tree Breeding and Cultivation | Yang W.,Chinese Academy of Forestry | Jiang Z.,Chinese Academy of Forestry | And 3 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2011

Thuja sutchuenensis Franch. is a critically endangered plant that is endemic to China. Currently, no research has addressed its endangered status from the perspective of its photosynthetic mechanism. Light is one of the most important environmental factors that can affect plant survival and growth and could become a major limiting factor for natural regeneration. Therefore, we focused on the adaptive ability of T. sutchuenensis seedlings under three light levels (L0 = full light; L1 = 50% full light; L2 = 25% full light) by comparing their photosynthetic capacity, chlorophyll fluorescence parameters, and chlorophyll content. We found that shading resulted in increases in the apparent quantum efficiency (α) and maximum leaf net photosynthetic rate (P max). At lower light levels, the dark respiration rate (R d), light compensation point (LCP), and light saturation point (LSP) declined. For the chlorophyll fluorescence parameters, PS II primary energy conversion efficiency (Fv / Fm), PS II potential activity (Fv / Fo), and photochemical efficiency of PS II in the light (Fv'/ Fm') were significantly higher at lower light levels than at L0, with parameters at L2 higher than at L1. Non- photochemical quenching (NPQ) also had a higher value under shade than under full light, and peaked at L1. With a decrease in light intensity, photochemical quenching (PQ) and the electron transport rate (ETR) decreased. Shading also caused a significant increase in leaf chlorophyll content (Chla + Chlb) per cm 2. These results indicate that T. sutchuenensis can tolerate a wide range light conditions, especially low light, and has internal regulatory mechanisms for responding to light level. Therefore, low light under canopy cannot be the decisive limiting factor for natural regeneration of T. sutchuenensis populations.

Chu J.,Key Laboratory of Tree Breeding and Cultivation | Yang H.,Qingdao Agricultural University | Lu Q.,Chinese Academy of Forestry | Zhang X.,Key Laboratory of Tree Breeding and Cultivation
AoB PLANTS | Year: 2015

Some endemic shrubs in arid and semiarid ecosystems are in danger of extinction, and yet they can play useful roles in maintaining or restoring these ecosystems, thus practical efforts are needed to conserve them. The shrubs Amygdalus pedunculata Pall., Amygdalus mongolica (Maxim.) Ricker and Ammopiptanthus mongolicus (Maxim. ex Kom.) Cheng f. are endemic species in arid and semiarid regions of northern China, where rangeland desertification is pronounced due to chronic overgrazing. In this study, we tested the hypothesis that these endemic shrubs have developed adaptations to arid and semiarid environments and could play critical roles as nurse species to initiate the process of rangeland recovery. Based on careful vegetation surveys, we analysed the niches of these species in relation to precipitation, temperature and habitats. All sampling plots were categorized by these endemics and sorted by the non-metric multidimensional scaling method. Species ratios of each life form and species co-occurrence rates with the endemics were also evaluated. Annual average temperature and annual precipitation were found to be the key factors determining vegetation diversity and distributions. Amygdalus pedunculata prefers low hills and sandy land in temperate semiarid regions. Amygdalus mongolica prefers gravel deserts of temperate semiarid regions. Ammopiptanthus mongolicus prefers sandy land of temperate arid regions. Communities of A. pedunculata have the highest diversity and the largest ratios of long-lived grass species, whereas those of A. mongolicus have the lowest diversity but the largest ratios of shrub species. Communities of A. mongolica are a transition between the first two community types. These findings demonstrate that our focal endemic shrubs have evolved adaptations to arid and semiarid conditions, thus they can be nurse plants to stabilize sand ground for vegetation restoration. We suggest that land managers begin using these shrub species to restore degraded rangelands as part of a general conservation effort. © The Authors 2015.

Li W.,Chinese Academy of Forestry | Li W.,Key Laboratory of Tree Breeding and Cultivation | Qian Y.-Q.,Chinese Academy of Forestry | Qian Y.-Q.,Key Laboratory of Tree Breeding and Cultivation | And 6 more authors.
Gene | Year: 2014

Quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) is a sensitive technique for normalization of the gene expression level of target genes. Buffalograss ( Buchloe dactyloides), a warm-season turfgrass with strong abiotic stress resistance, is widely used in North China. Up to now, no work was performed to evaluate the reference genes in buffalograss. In this study, the expression profiles of ten potential reference genes were examined by qRT-PCR in 24 buffalograss samples, which were subjected to a different treatment (salt, osmotic, cold and heat). Three qRT-PCR analysis methods (GeNorm, NormFinder, and Bestkeeper) were used to evaluate the stability of gene expression. The results indicated that DNAJ and β-ACTIN were the optimal reference genes for salt-treated leaves, and the combination of PP2A and GAPDH was better reference genes for PEG-treated leaves. Under cold stress, DNAJ and β-ACTIN showed less variety of expression level in leaves. DNAJ and GAPDH exhibited the most stable expression in heat-treated samples. To sum up, glyceral-dehyde-3-phosphate dehydrogenase ( GAPDH), β-ACTIN, DNAJ-like protein ( DNAJ) and protein phosphatase 2A ( PP2A) were selected as the most stable reference gene among all tested samples. To further validate the suitability of these reference genes, the expression levels of DREB2 (homologs of AtDREB2) were analyzed in parallel. Our results show that the best reference genes differed across different experimental conditions, and these results should enable better normalization and quantification of transcript levels in buffalograss in the future. © 2014 Elsevier B.V.

Hu Y.-B.,Key Laboratory of Tree Breeding and Cultivation | Hui G.-Y.,Key Laboratory of Tree Breeding and Cultivation
Beijing Linye Daxue Xuebao/Journal of Beijing Forestry University | Year: 2015

Analysis of spatial patterns of populations is an important approach to study the characteristics of populations, interaction among populations and relations between a population and its environment and has been a research focus in ecology for some time. The mingling degree is an index to describe spatial segregation among tree species, i.e., the probability that the nearest adjacent tree, a random occurrence in a mixed forest, belongs to another species. As yet, we are not aware of publications of any analysis of population distribution patterns by a direct use of this mingling degree, recognized not only as a clear and scientific index for describing tree species segregation, but is also a simple and effective way for data collection and measurements. We propose a new method, DM, of testing population distributions by analyzing the relationship between expected and observed values of this mingling degree. A statistical significance test method was introduced. The method was applied to measure the distribution pattern of tree species in a natural mixed forest in Xiaolong Mountain, Gansu Province, northwestern China. Compared with the classic aggregation index R, the test accuracy of DM is 100%, suggesting that the theoretical defect of the aggregation index R has been avoided. Application of this method will enhance research on the spatial structure of stands, based on the relationships between adjacent trees. ©, 2015, Beijing Forestry University. All right reserved.

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