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991.
Root respiration is a critical physiological trait involved in root resource acquisition strategies, yet it is less represented in root trait syndrome. Here we compiled a large dataset of root respiration associated with root chemical and morphological traits from 245 plant species. Our results demonstrated that root respiration correlated positively with root nitrogen concentration (RNC) and negatively with root tissue density (RTD) across and within woody and non‐woody species. However, the relationships between root respiration and specific root length (SRL) and root diameter (RD) were weak or even insignificant. Such root respiration–traits relationships were not completely in line with predictions by the root economics spectrum (RES). Furthermore, the principal component analysis showed that root trait syndrome was multidimensional. Root respiration was associated more strongly with the RNC‐RTD axis (the classical RES) than with the orthogonal SRL‐RD axis for woody species, but not for non‐woody species. Collectively, the linkages of root physiological, chemical, and morphological traits provide a better understanding of root trait covariation and root resource acquisition strategies. 相似文献
992.
Wu Yifan Hu Jingkai Jin Xuanjiang Li Xiao Wang Jinfeng Zhang Mengmeng Chen Jianglin Xie Shumin Qi Wenbao Liao Ming Jia Weixin 《中国病毒学》2021,36(5):1124-1132
Virologica Sinica - No avian H7N9 outbreaks have occurred since the introduction of H7N9 inactivated vaccine in the fall of 2017. However, H7N9 is still prevalent in poultry. To surveil the... 相似文献
993.
AimAs habitat loss continues to accelerate with global human population growth, identifying landscape characteristics that influence species occurrence is a key conservation priority in order to prevent global biodiversity loss. In South Africa, the arboreal samango monkey (Cercopithecus albogularis sp.) is threatened due to loss and fragmentation of the indigenous forests it inhabits. The aim of this study was to determine the habitat preferences of the samango monkey at different spatial scales, and to identify key conservation areas to inform management plans for this species.LocationThis study was carried out in the western Soutpansberg Mountains, which represents the northernmost population of samango monkeys within South Africa, and the only endangered subspecies (C. a. schwarzi).MethodsWe used sequentially collected GPS points from two samango monkey groups followed between 2012 and 2017 to quantify the used and available habitat for this species within the western Soutpansberg Mountains. We developed 2nd‐order (selection of ranging area), 3rd‐order (selection within range), and 4th‐order (feeding site selection) resource selection functions (RSFs) to identify important habitat features at each scale. Through scale integration, we identified three key conservation areas for samango monkeys across Limpopo Province, South Africa.ResultsHabitat productivity was the most important landscape variable predicting probability of use at each order of selection, indicating the dependence of these arboreal primates on tall‐canopy indigenous forests. Critical habitat across Limpopo was highly fragmented, meaning complete isolation between subpopulations is likely.Main conclusionsUnderstanding the habitat characteristics that influence samango monkey distribution across South Africa is crucial for prioritizing critical habitat for this species. Our results indicated that large, contiguous patches of tall‐canopy indigenous forest are fundamental to samango monkey persistence. As such, protected area expansion of large forest patches and creation of forest corridors are identified as key conservation interventions for this species. 相似文献
994.
海洋放线菌生活的环境如养分、光照、氧气浓度、压力、盐度和温度等与陆地环境存在极大差异,因此海洋放线菌形成了独特的生物化学代谢和生理能力。近年来,海洋放线菌成为生物资源开发和研究的热点。海洋放线菌分布广泛,种类多样。海洋放线菌活性代谢产物具有极强的医药应用潜力,其代谢产物的功能研究及重要代谢产物的开发成为海洋放线菌研究的重要方向。此外,海洋放线菌在环境保护以及生产应用等方面展现出的潜能,引起研究人员极大的兴趣。本文结合近年来海洋放线菌的分离种类与生境、海洋放线菌的研究策略与手段以及代谢产物功能多样性进行了归纳总结,以期对海洋放线菌的认识更全面、系统。 相似文献
995.
996.
生物安全是国家安全的重要组成部分,《中华人民共和国生物安全法》通过了全国人大常委会的审议,并自2021年4月15日起施行。生物遗传资源是国家可持续发展的重要战略资源和国家安全的重要物质保障,目前已成为世界各国资源争夺的新领域,随着生物技术、分子生物学、生物信息学的迅速发展,对生物遗传资源的安全管理,离不开法律法规等制度的规范。《生物安全法》的出台完善了中国的法律、法规等管理制度,但还需要进一步的细化。首先阐述了《生物安全法》的立法意义,介绍了《生物安全法》的层级地位及立法进程;然后,在《生物安全法》实施背景下简要分析了生物遗传资源的定义及其安全管理面临的问题、国内外生物遗传资源安全管理的现状,阐述了《生物安全法》的出台对完善中国生物遗传资源管理的重要意义;最后,从法律框架、法律法规内容和科学技术层面提出如何更好地推进与落实《生物安全法》出台后中国生物遗传资源的安全管理。 相似文献
997.
目的:研究我国山药种质资源遗传多样性,为合理利用资源和开展选育种工作提供理论依据。方法:以国内94份山药种质资源为材料,采用SRAP标记并通过NTSYS2.10软件进行SHAN聚类分析、PROJECTION主成分分析;利用POPGENE软件估算遗传多样性参数。结果:从49对SRAP引物中筛选出30对能产生稳定清晰可辨的扩增产物的引物,共扩增出754条DNA带,其中多态性条带616条,占总条带的81.7%。聚类结果表明:当遗传相似系数(GS)为0.822时,可将94份资源分为5类:第Ⅰ类20份、第Ⅱ类43份、第Ⅲ类7份、第Ⅳ类3份、第Ⅴ类21份。第Ⅰ、Ⅱ、Ⅲ、Ⅴ类分别为薯蓣、褐苞薯蓣、山薯和参薯。主成分分析结果显示:第一与第二主成分可解释88.34%(82.10%和6.24%)的遗传总变异。遗传多样性参数分析表明:比较5个遗传多样性参数值,5个群体的遗传多样性水平表现为Ⅰ>Ⅴ>Ⅲ>Ⅱ>Ⅳ,第Ⅰ类(薯蓣)遗传多样性水平高;山药遗传群体间遗传分化系数为51.88%,大部分差异存在于群体之间,群体间遗传分化高。结论:山药种质资源丰富且群体遗传分化高,有利于山药新品种的选育。SRAP标记可有效应用于山药种质资源的鉴别和遗传多样性分析。通过DNA指纹鉴定技术鉴别山药品种具有重要性与紧迫性。 相似文献
998.
We examined the effect of age differences on competition type in individuals of a scramble‐type strain of Callosobruchus maculatus (F.). When oviposition of two individuals on a bean was manipulated to introduce time intervals using two lines with different adult body colors, the frequency of two‐adult emergence decreased with the introduction of sequential oviposition. This result indicates that an age difference between two individuals induces contest competition. The frequency of adult emergence in older individuals decreased, whereas in younger individuals it increased with the introduction of sequential oviposition. Using a dissecting microscope, we observed that bodies of older individuals that died in the bean during the 4‐day oviposition interval were crushed at the pupal stage under the pupal chambers of younger individuals. These results show that an age difference between two larvae in a bean causes contest competition due to one‐sided interference by a younger individual during pupation of an older individual. Based on these experimental results, we discuss the ecological cause of contest competition and the population‐level consequences of identified interactions in scramble‐type C. maculatus. 相似文献
999.
In cooperatively breeding species, the fitness consequences of producing sons or daughters depend upon the fitness impacts of positive (repayment hypothesis) and negative (local competition hypothesis) social interactions among relatives. In this study, we examine brood sex allocation in relation to the predictions of both the repayment and the local competition hypotheses in the cooperatively breeding long-tailed tit Aegithalos caudatus. At the population level, we found that annual brood sex ratio was negatively related to the number of male survivors across years, as predicted by the local competition hypothesis. At an individual level, in contrast to predictions of the repayment hypothesis, there was no evidence for facultative control of brood sex ratio. However, immigrant females produced a greater proportion of sons than resident females, a result consistent with both hypotheses. We conclude that female long-tailed tits make adaptive decisions about brood sex allocation. 相似文献
1000.
Maria Cristina Vallejo Mario A. Pérez Rincón Joan Martinez‐Alier 《Journal of Industrial Ecology》2011,15(2):245-267
This article characterizes the societal metabolism of the Colombian economy, identifying the main factors of natural resources use, overuse, or exhaustion. The environmental sustainability of a country depends to a large extent on the size of the economy compared to the available resource base. Material flow indicators provide an assessment of size or scale of economies. Direct material flow indicators are used to analyze the ecological dimension of economic activity in the period 1970–2007. Some resource extraction conflicts are briefly described in the light of material flow analysis. Foreign and domestic demand promotes increasing extraction and export of domestic natural resources. This is sometimes related to an irreversible deterioration of the local environment. The concept of “ecologically unequal exchange” with the rest of the world is analyzed in this context. Colombia has a large and growing negative physical trade balance, whereas per capita use of materials is still about half of the industrial countries’ average. 相似文献