Correlation between the animal community structure and environmental factors in Jialiang and Boduo caves of Guizhou Province, China

1045 samples collected in Boduo cave belong to 3 phyla, 6 classes, 13 orders, 27 families and 45 species or groups. 469 samples collected in Jialiang cave were subordinated to 3 phyla, 6 classes, 9 orders, 24 families and 52 species or groups. According to the analysis of the community diversity, the communities that have the highest values of richness, diversity, maximum diversity, evenness, dominance and community similarity are D (8.3223), D (3.4677), D (3.8286), D (0.9057), C (0.0404) and D-E (0.6611), respectively. According to the analysis of Pearson correlation, the content of organic matter in soil is strongly positively related to species number, species richness, community diversity and maximum community diversity, and is significantly positively related to the evenness. The content of CO2 in air is opposite to the above result and is negatively related to species number, species richness, community diversity, maximum community diversity and evenness. The results indicate that the contents of organic matter and CO2 are the important factors influencing the community structure of cave animals.     

Correlation analysis of Normalized Different Vegetation Index (NDVI) difference series and climate variables in the Xilingole steppe, China from 1983 to 1999

There is a crucial need in the study of global change to understand how terrestrial ecosystems respond to the climate system. It has been demonstrated by many researches that Normalized Different Vegetation Index (NDVI) time series from remotely sensed data, which provide effective information of vegetation conditions on a large scale with highly temporal resolution, have a good relation with meteorological factors. However, few of these studies have taken the cumulative property of NDVI time series into account. In this study, NDVI difference series were proposed to replace the original NDVI time series with NDVI difference series to reappraise the relationship between NDVI and meteorological factors. As a proxy of the vegetation growing process, NDVI difference represents net primary productivity of vegetation at a certain time interval under an environment controlled by certain climatic conditions and other factors. This data replacement is helpful to eliminate the cumulative effect that exist in original NDVI time series, and thus is more appropriate to understand how climate system affects vegetation growth in a short time scale. By using the correlation analysis method, we studied the relationship between NOAA/AVHRR ten-day NDVI difference series and corresponding meteorological data from 1983 to 1999 from 11 meteorological stations located in the Xilingole steppe in Inner Mongolia. The results show that: (1) meteorological factors are found to be more significantly correlation with NDVI difference at the biomass-rising phase than that at the falling phase; (2) the relationship between NDVI difference and climate variables varies with vegetation types and vegetation communities. In a typical steppe dominated by Leymus chinensis, temperature has higher correlation with NDVI difference than precipitation does, and in a typical steppe dominated by Stipa krylovii, the correlation between temperature and NDVI difference is lower than that between precipitation and NDVI difference. In a typical steppe dominated by Stipa grandis, there is no significant difference between the two correlations. Precipitation is the key factor influencing vegetation growth in a desert steppe, and temperature has poor correlation with NDVI difference; (3) the response of NDVI difference to precipitation is fast and almost simultaneous both in a typical steppe and desert steppe, however, mean temperature exhibits a time-lag effect especially in the desert steppe and some typical steppe dominated by Stipa krylovii; (4) the relationship between NDVI difference and temperature is becoming stronger with global warming. __________ Translated from Acta Phytoecologica Sinica, 2005, 29(5): 753–765 [译自: 植物生态学报]     

Point pattern analysis of different age-classes of Larix principis-rupprechtii in Luya Mountain Reserve, Shanxi Province, China

Larix principis-rupprechtii forest is an important vegetation formation and has a large distribution area in Luya Mountain Reserve, China. Spatial pattern analysis on individual trees in different age-classes of Larix principis-rupprechtii was made in this paper. Here, we employed the technique of point pattern analysis, which could analyze patterns under all scales along a gradient. It was based on spatial mapped points of individual distribution. The results of this study showed that the densities of the five age-classes varied in the order: age-class 3 > age-class 4 > age-class 5 > age-class 2 > age-class 1. Although age-classes 1 and 2 have much fewer individuals than other three age-classes do, the population was stable at present. However, it would be necessary to take some measures for improving population regeneration for a long-time view. The individuals of all age-classes focused on clumping distribution in space; however, their distribution pattern varied with the change of scale. This mainly depended on biological features of Larix principis-rupprechtii and forest environments, but it also meant that the scale was an important factor in controlling spatial distribution pattern of tree individuals. The feature of clumping distribution became more significant with the increase of age. The relationships between individuals in different age-classes were almost all significantly correlated with each other. These associations became more significant within the older age-classes. This suggested that the individuals of different age-classes were interdistributed, by which the population could get benefits in resource utilization. The technique of point pattern analysis is effective and easy to be used in species pattern study. Its results are more closer to the reality, especially for community structure. Translated from Acta Ecologica Sinica, 2004, 24(1): 35–40 [译自: 生态学报]     

北京西部山区胡枝子种群研究: 个体和构件生物量

通过对北京西部山区胡枝子(Lespedeza bicolor Turcz.)种群个体和构件地上生物量进行系统研究。结果表明, 种群(总和)个体和各构件地上生物量积累与年龄的关系均可用方程式Y=axb表示。不同种群的植株个体和构件生物量有显著性不同(P<0.05), 在海拔910-1 100 m的山脊林缘的种群个体和构件地上生物量较其它种群大, 植株地上营养构件的生物量比率较小, 而繁殖构件生物量比率较大; 不适生境中的种群则反之。种群个体生长和各构件生物量动态与环境条件关系密切。构件生物量比率也随着年龄的增长而有所变化。叶生物量比率随年龄增加而减小; 枝构件生物量比率随年龄增加而增大; 繁殖构件的生物量比率随年龄增加先增后减。依据相关指数R2, 筛选各构件生物量估计的最优模型: 枝、枝叶生物量和地上生物量均为m(DW)= a(D2H1)b, 叶生物量和花果生物量均为m(DW)=a(D)b。     

Biological effects of low-energy C ion implantation on sesame (Sesamum indicum L.)

Field cultivation experiments on white sesame (Sesamum indicum L.)seeds implanted with low-energy C ion showed that different dosages of C ion implantation produce different biological effects.Sesame plants in 6 different dosage groups with C ion density respectively at 1×1011,1×1012,1×1015,5×1015,1×1016,5×1016 ion/cm2 were superior to the control group in plant height,leaf number,stalk diameter and leaf size.Further,sesame plants in these groups flower and seed earlier than those in the control group,and single plant yield also increased.Of all the groups,the 5×1015 ion/cm2 dosage group yielded the best effect,whereas the 1×1017/cm2 dosage group showed an evident inhibitory effect of ion implantation on the germination and growth of the sesame seeds.     

Point pattern analysis of different age-classes of Larix principis-rupprechtii in Luya Mountain Reserve, Shanxi Province, China

Larix principis-rupprechtii forest is an important vegetation formation and has a large distribution area in Luya Mountain Reserve,China.Spatial pattern analysis on individual trees in different age-classes of Larix principisrupprechtii was made in this paper.Here,we employed the technique of point pattern analysis,which could analyze patterns under all scales along a gradient.It was based on spatial mapped points of individual distribution.The results of this study showed that the densities of the five age-classes varied in the order:age-class 3＞age-class 4＞age-class 5＞age-class 2＞age-class 1.Although age-classes 1 and 2 have much fewer individuals than other three age-classes do,the population was stable at present.However,it would be necessary to take some measures for improving population regeneration for a long-time view.The individuals of all age-classes focused on clumping distribution in space;however,their distribution pattern varied with the change of scale.This mainly depended on biological features of Larix principis-rupprechtii and forest environments,but it also meant that the scale was an important factor in controlling spatial distribution pattern of tree individuals.The feature of clumping distribution became more significant with the increase of age.The relationships between individuals in different age-classes were almost all significantly correlated with each other.These associations became more significant within the older age-classes.This suggested that the individuals of different age-classes were interdistributed,by which the population could get benefits in resource utilization.The technique of point pattern analysis is effective and easy to be used in species pattern study.Its results are more closer to the reality,especially for community structure.     

Analysis of nutrient components of food for Asian elephants in the wild and in captivity

Thirty-seven wild plants as food for Asian elephants in the field in Simao,Yunnan province,China and five cultivated plants as food for captive elephants in the Beijing Zoo were collected and analyzed for their main nutrient components.Protein,fat,fiber,dry material,ash as well as major microelements:calcium,kalium,zincum,sodium in the food were analyzed by standard methodology.No significant differences were found between the wild plants taken in the field and forage provided in captivity.However,the calcium content in the forage is significantly less than the average of those in the wild plants.It is suggested that the increase in calcium intake may contribute to the relief of low plasma calcium diseases of elephants in captivity.     

Protecting exons from deleterious R-loops: a potential advantage of having introns

Background  

Accumulating evidence indicates that the nascent RNA can invade and pair with one strand of DNA, forming an R-loop structure that threatens the stability of the genome. In addition, the cost and benefit of introns are still in debate.     

亚洲虎种群恢复的机遇与挑战

虎(Panthera tigris)作为顶级捕食者, 对维持森林生态系统服务和结构完整性有着重要作用, 是研究和保护工作的旗舰物种。历史上, 虎曾广泛分布于亚洲大部分地区, 如今仅分布于南亚、东南亚和东北亚的破碎化栖息地, 各区域种群处于濒危或极度濒危状态。准确了解野生虎的种群状态和生态需求信息对于科学开展保护和恢复工作至关重要。本文通过综述近几十年的研究文献, 总结了野生虎种群现状和主要威胁因素, 评价了已有研究的重点与不足, 为未来亚洲虎种群的研究和保护提出了建议。目前与虎相关的研究主要集中在分布范围最广的孟加拉虎(P. t. tigris)和东北虎(P. t. altaica) 2个亚种, 而最急需关注的其他亚种仍研究不足。经过近十几年的努力和保护投入, 目前野生虎种群数量已从2010年的大约3,200只恢复到现在约4,500只, 但在越南、柬埔寨和老挝3个国家已经灭绝。虎面临的主要威胁包括持续的栖息地破坏和隔离、猎物缺乏、近交衰退、人虎冲突、贸易与盗猎和疾病威胁等。未来的研究和保护工作需要加强种群和栖息地连通性恢复、个体重引入、疾病管控以及加强跨境合作和反盗猎等。     

Single-cell transcriptomics reveals cell type diversity of human prostate

Extensive studies have been performed to describe the phenotypic changes occurring during malignant transformation of the prostate. However, the cell types and associated changes that contribute to the development of prostate diseases and cancer remain elusive, largely due to the heterogeneous composition of prostatic tissues. Here, we conduct a comprehensive evaluation of four human prostate tissues by single-cell RNA sequencing (scRNA-seq) to analyze their cellular compositions. We identify 18 clusters of cell types, each with distinct gene expression profiles and unique features; of these, one cluster of epithelial cells (Ep) is found to be associated with immune function. In addition, we characterize a special cluster of fibroblasts and aberrant signaling changes associated with prostate cancer (PCa). Moreover, we provide insights into the epithelial changes that occur during the cellular senescence and aging. These results expand our understanding of the unique functional associations between the diverse prostatic cell types and the contributions of specific cell clusters to the malignant transformation of prostate tissues and PCa development.