Wang Y.-G.,Chinese Academy of Forestry |
Wang Y.-G.,Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration |
Yang X.-H.,Chinese Academy of Forestry |
Yang X.-H.,Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration |
And 2 more authors.
Beijing Linye Daxue Xuebao/Journal of Beijing Forestry University | Year: 2010
The western Ordos Plateau is a distribution center of many endangered shrub species, which have suffered sand burial to various degrees during the last few years. According to the survey data of spatial point pattern of shrub communities in the arid desert of western Ordos Plateau in 2006, we investigated the structure and spatial pattern of shrub communities under different levels of sand burial to reveal its effects on shrub communities in this area. Three indices of spatial pattern based on the nearest neighbor distance, i. e. the F(t), G(t) and J(t) functions, were selected. The results indicate that sand burial is an important factor causing the extinction of sand intolerant shrubs. The number of sand intolerant shrubs gradually reduced with an increase in the depth of sand burial. For sand tolerant shrubs, shallow sand burial promoted their germination and growth, but this positive role changed to a negative effect when the depth of sand burial exceeded a specific value, showing at first an increase in the number of sand tolerant shrubs and then a decrease. Both sand tolerant and intolerant shrubs showed a random distribution pattern on a small scale under various levels of sand burial, with a significantly negative correlation under shallow sand burial. When the depth of sand burial exceeded 12 cm, the shrubs appeared to be sparsely distributed and without any significant correlation. Sand burial is an important driving force in community degradation, which tends to cause the singleness and aging of shrub species in the community and difficulty to regenerate. Source
Zhu W.,Chinese Academy of Forestry |
Zhu W.,Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration |
Chu Y.,Chinese Academy of Forestry |
Chu Y.,Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration |
And 10 more authors.
Journal of Forestry Research | Year: 2015
Microbe communities in rhizosphere ecosystems are important for plant health but there is limited knowledge of them in the rhizospheres of genetically modified (GM) plants, especial for tree species. We used the amplitude sequencing method to analyze the V4 regions of the 16S rRNA gene to identify changes in bacterial diversity and community structure in two GM lines (D520 and D521), one non-genetically modified (non-GM) line and in uncultivated soil. After chimera filtering, 468.133 sequences in the domain Bacteria remained. There were ten dominant taxonomic groups (with >1 % of all sequences) across the samples. 241 of 551 genera (representing a ratio of 97.33 %) were common to all samples. A Venn diagram showed that 1.926 operational taxonomic units (OTUs) were shared by all samples. We found a specific change, a reduction in Chloroflexi, in the microorganisms in the rhizosphere soil planted with poplars. Taken together, the results showed few statistical differences in the bacterial diversity and community structure between the GM line and non-GM line, this suggests that there was no or very limited impact of this genetic modification on the bacterial communities in the rhizosphere. © 2015 Northeast Forestry University and Springer-Verlag Berlin Heidelberg Source