Habitats with different features such as soil depth and soil/rock conditions can provide favorable environments for species with different requirements, while anthropogenic disturbances normally exert additional effec...Habitats with different features such as soil depth and soil/rock conditions can provide favorable environments for species with different requirements, while anthropogenic disturbances normally exert additional effects on species composition. However, specific studies have rarely been conducted in the degraded karst regions of Southwest China despite the high heterogeneity of karst habitats and past human disturbances. In this study, woody species richness and composition on rocky outcrops on a typical karst hillslope were investigated and compared with those of nearby matrices on shallow and rocky soil. Our results showed that matrix vegetation was more diverse in genera and species than vegetation on rocky outcrops. This might relate to the contrasting substrate features and different disturbance histories of these two habitats. Unlike the significant effect of slope on species richness of the matrix vegetation, rocky outcrops exhibited no significant differences between upper and lower slope positions, largely because their microhabitats were similar in different slope positions. Although the study area has been reforested naturally for about 30 years, woody species of the matrix vegetation were still dominated by pioneer shrub species. Rocky outcrops were dominated by late-successional tree species, which was primarily related to their isolated features and resistance to certain disturbances. Most of these late-successional species were not habitat endemics, indicating the possibility for their encroachment into surrounding the matrix. From this aspect, further studies will be necessary to identify and address the limiting factors for the encroachment of these late-successional species into the surrounding environment.展开更多
Dear Editor,The placenta connecting the fetus to the matermal uterus provides material exchange and an immune-tolerant environment for the embryo in all eutherian mammals(Shao et al.,2022).The representative mouse pla...Dear Editor,The placenta connecting the fetus to the matermal uterus provides material exchange and an immune-tolerant environment for the embryo in all eutherian mammals(Shao et al.,2022).The representative mouse placenta displays a multilayered structure with distinct characteristics and functions,including the matermal decidua,junctional zone,and labyrinth layer(Marsh and Blelloch,2020).The decidua,which is thought to be derived from the matermal endometrium(and further undergoes decidualization),provides an anchor for fetal trophoblast invasion.The junctional zone predominantly contains spongiotrophoblasts(SpT),glycogen trophoblasts(GlyT),and trophoblast giant cells(TGCs).The labyrinth is the innermost two-layer structure,which mainly consists of syncytiotrophoblast cells(SynTI and SynTII),sinusoidal TGCs(S-TGCs),and fetal endothelial cells(Simmons and Cross,2005).展开更多
基金supported by the National Key Research and Development Program of China(2016YFC0502402)the National Natural Science Foundation of China(31570428)+1 种基金the Young Scholars of Western China,Chinese Academy of Sciences(for Y.N.)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(2018397)
文摘Habitats with different features such as soil depth and soil/rock conditions can provide favorable environments for species with different requirements, while anthropogenic disturbances normally exert additional effects on species composition. However, specific studies have rarely been conducted in the degraded karst regions of Southwest China despite the high heterogeneity of karst habitats and past human disturbances. In this study, woody species richness and composition on rocky outcrops on a typical karst hillslope were investigated and compared with those of nearby matrices on shallow and rocky soil. Our results showed that matrix vegetation was more diverse in genera and species than vegetation on rocky outcrops. This might relate to the contrasting substrate features and different disturbance histories of these two habitats. Unlike the significant effect of slope on species richness of the matrix vegetation, rocky outcrops exhibited no significant differences between upper and lower slope positions, largely because their microhabitats were similar in different slope positions. Although the study area has been reforested naturally for about 30 years, woody species of the matrix vegetation were still dominated by pioneer shrub species. Rocky outcrops were dominated by late-successional tree species, which was primarily related to their isolated features and resistance to certain disturbances. Most of these late-successional species were not habitat endemics, indicating the possibility for their encroachment into surrounding the matrix. From this aspect, further studies will be necessary to identify and address the limiting factors for the encroachment of these late-successional species into the surrounding environment.
基金supported by the National Key Research and Development Program of China(2018YFE0201100 to Lw.,2019YFA0110901 to G.F,2022YFA1104101 to GF,2022YFA1104300 to CL.)the Youth Innovation Promotion Association,CAS(2019084 to GF),informatization Plan of Chinese Academy of Sciences(CAS-Wx20215F-0101 to GF)the National Natural Science Foundation of China(31972895 toLw).
文摘Dear Editor,The placenta connecting the fetus to the matermal uterus provides material exchange and an immune-tolerant environment for the embryo in all eutherian mammals(Shao et al.,2022).The representative mouse placenta displays a multilayered structure with distinct characteristics and functions,including the matermal decidua,junctional zone,and labyrinth layer(Marsh and Blelloch,2020).The decidua,which is thought to be derived from the matermal endometrium(and further undergoes decidualization),provides an anchor for fetal trophoblast invasion.The junctional zone predominantly contains spongiotrophoblasts(SpT),glycogen trophoblasts(GlyT),and trophoblast giant cells(TGCs).The labyrinth is the innermost two-layer structure,which mainly consists of syncytiotrophoblast cells(SynTI and SynTII),sinusoidal TGCs(S-TGCs),and fetal endothelial cells(Simmons and Cross,2005).
