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1

Genetic and epigenetic alterations in hybrid and derived hexaploids between Brassica napus and B. oleracea revealed by SSR and MSAP analysis

100%
Li Q., Rana K., Xiong Z., Ge X., Li Z., Song H., Qian W.
Acta Physiologiae Plantarum
|
2019
|
tom 41
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nr 05
Polyploidization causes ‘genomic shock’ at the genetic and epigenetic levels relative to the parental species. However, few studies have compared the genetic and epigenetic alterations during the process of polyploidization by interspecific hybridization in Brassica species. In the present study, the early generations of hexaploid derived from a triploid hybrid between Brassica napus cv. ‘Zhongshuang 9’ and B. oleracea cv. ‘SWU01’ were developed, and used to detect genetic and epigenetic alterations together with triploid and two parental lines using simple sequence repeats (SSRs) and methylation-sensitive amplified polymorphisms (MSAPs). The derived hexaploids had relatively stable karyotype (69.84% euploid chromosome segregation in S0, 100% and 72.7% hexaploid karyotype in S1 and S2, respectively) and good fertility (88.75% ± 5.43% for pollen fertility, 4.68 ± 3.25 seeds/pod for self pollination and 13.55 ± 3.66 seeds/pod for open pollination), but wide morphologic characters. Compared with the parental lines, the triploid exhibited 13.08% new SSR alleles (17 of 130) and up to 26.45% new MSAP alleles (65 of 246), indicating that interspecific hybridization caused genetic and epigenetic alterations. No change in SSRs and 33.74% alterations in MSAP alleles (83/246) was observed between the triploid and hexaploid S0, suggesting chromosome doubling only caused epigenetic alteration. On average of 39.23% ± 5.78% of DNA methylation alterations and 6.35% ± 3.69% of SSR alterations occurred among the S2, S1, and S0 generations. It indicated that genetic alteration was caused by interspecific hybridization and generation descent of hexaploid, whereas epigenetic alteration resulted from interspecific hybridization, chromosome doubling and generation descent. It is interesting to find stronger epigenetic changes than genetic changes brought on during the processes of hexaploidization between B. napus and B. oleracea. It also found the average genetic distance between hexaploid S2 and hexaploid S1 (SSR 0.056 ± 0.029, MSAP 0.337 ± 0.201) was further than that between hexaploid S1 and hexaploid S0 (SSR 0.023 ± 0.009, MSAP 0.178 ± 0.126), suggesting more genetic variance in the hexaploid S2 generations than hexaploid S1.
2

Spatiotemporal variations of growing-season NDVI associated with climate change in northeastern China’s permafrost zone

100%
Gua J., Hu Y., Xiong Z., Yan X., Ren B., Bu R.
Polish Journal of Environmental Studies
|
2017
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tom 26
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nr 4
Vegetation is an essential component of terrestrial ecosystems, and it plays an important role in regulating climate change, the carbon cycle, and energy exchange. And permafrost is extremely sensitive to climate change. In particular, aboveground vegetation on permafrost has great sensitivity to that change. The permafrost zone of northeastern China, within middle and high latitudes of the northern hemisphere, is the second-largest region of permafrost in China. It is at the southern edge of the Eurasian cryolithozone. This study analyzes growing-season spatiotemporal variation of the normalization difference vegetation index (NDVI) in this permafrost zone and the correlation between NDVI and climate variables during 1981-2014. Mean growing-season NDVI significantly increased by 0.0028 yr⁻¹ over the entire permafrost zone. The spatial dynamics of vegetation cover in the zone had strong heterogeneity on the pixel scale. Pixels that showed increasing trends accounted for 80% of the permafrost area, and were mostly found in the permafrost zone with the exception of western steppe regions. Pixels that showed decreasing trends (approximately 20% of the permafrost area) were mainly in the cultivated and steppe portions of the study area. Our results indicated that temperature was the dominant influence on vegetation growth during the growing season in most permafrost zones.
3

Plant diversity and vegetation structures in the understory of mixed boreal forests under different management regimes

100%
Wu W., Hu Y., Li Y., Gong J., Chen L., Chang Y., Xiong Z.
Polish Journal of Environmental Studies
|
2016
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tom 25
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nr 4
Community surveys were performed in 30 forest stands with similar conditions under different management types in forests of northeastern China to study the influence of forest management on plant biodiversity. We evaluated this effect by calculating and analyzing species richness, vegetation structure, and aboveground biomass. Large variations in species composition, vegetation structure, species richness, and aboveground biomass were evident among the three types of common management types investigated (cut shrub tending, selective cutting, and understory planting). The species composition of the herb layer changed more than that of the shrub layer, and herbs were more vulnerable to impact from human activities. Each management type reduced the plant coverage, and this was most significant in planted plots. We found that in the cut shrub tending plots, the shrub height increased over time. The mean fresh weight of the control group was about 2 kg·m-2, which was about two-fold the selective cutting group (1 kg·m-2) and five-fold the understory planting group (0.4 kg·m-2). Our results also showed that management types in mixed forest stands strongly impact species diversity and, to some extent, environmental capacity, with negative effects on biodiversity.
4

Potential suitable habitat distribution and conservation strategy for the Siberian crane (Grus leucogeranus) at spring stopover sites in Northeastern China

84%
Wen D., Hu Y., Xiong Z., Chang Y., Li Y., Wang Y., Liu M., Zhu J.
Polish Journal of Environmental Studies
|
2020
|
tom 29
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nr 5
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