秦岭太白山北坡土壤拮抗性放线菌分布及特性

以太白山北坡12个不同海拔高度的代表性土样为研究对象,采用皿内琼脂块法筛选拮抗性放线茵.结果表明:在太白山北坡不同海拔高度土壤中生存着大量拮抗性放线菌,在分离出的141株放线菌中,有82.3％的放线菌对21种靶标菌有拮抗作用.其中,海拔800～1845、3488、3655和3670 m土壤中的拮抗性放线菌分别占其总数73.7％～86.8％、81.3％、78.9％及82.3％,在海拔1200～2300及3400 m以上土壤中分离到的广谱强拮抗性放线菌占其总数的42.1％.在拮抗性放线菌中,对金黄色葡萄球菌有强拮抗性的放线菌占拮抗菌总数的24.1％,对棉花黄萎病、草莓疫霉及人参根腐病原菌等多种植物病原菌有强拮抗性的放线菌分别占拮抗菌总数的2.4％、6.9％和11.2％.土壤放线菌拮抗潜势SAAP可作为评价土壤中拮抗性放线菌资源蕴藏量的定量指标.     

芋螺毒素基因资源研究进展

芋螺毒素和微生物的次生代谢产物与植物的生物碱一样,具有生物多样性的特点。芋螺毒素特有的二硫键骨架和化学修饰后特异的空间结构,使其具有特异的稳定性和药理学活性。对芋螺毒素基因的分析和新型基因的克隆筛选,是深入研究各种受体、离子通道及其亚型,进而在克隆表达的靶受体上设计和筛选高效新药的前提。芋螺毒素基因资源的研究在芋螺毒素新基因及其编码产物毒素肽的发现与利用方面发挥了重要作用。现对该领域的新进展进行论述。     

Changes in soil and vegetation following stabilisation of dunes in the southeastern fringe of the Tengger Desert, China

Properties of the soil and sand-binding vegetation were measured at five sites plus a control on dunes of the Tengger Desert stabilized for periods of up to 50 years. In the topsoil, fine particles, total N, P, K and organic matter increased significantly with increasing site age. However, there were no significant changes in deeper soil profiles (>0.4 m depth). Soil pH, calcium carbonate content, and total salt content tended to increase with age. Soil water in the topsoil changed little with increasing age, but was closely related to rainfall during the 50-year period. For deeper soil layers (0.4–3.0 m) soil water decreased significantly with age. After revegetation, the number of herbaceous species increased up to 30 years and then levelled off to 12–14 species, whereas the number of shrub species decreased from the 10 initial sand-binding species to only 3 species. Shrub cover decreased from a highest average of about 33% to the current 9%, whereas cover and biomass of herbaceous species increased throughout succession from 1956 to 2006. The development of soil and cryptogamic crusts on the surface of stabilized dunes enhanced the colonization and establishment of herbaceous plants due to increasing water availability, clay and silt content and soil nutrients. We propose that changes in properties of the surface soil led to increased interception of water, favoring shallow rooted grasses and forbs over perennial shrubs.     

Pond canopy cover: a resource gradient for anuran larvae

1. The gradient in pond canopy cover strongly influences freshwater species distributions. This study tested the effects of canopy cover on the performance of two species of larval anurans, a canopy cover generalist (Rana sylvatica, the wood frog) and an open‐canopy specialist (R. pipiens, the leopard frog), and tested which factors co‐varying with canopy cover mediate these effects. 2. A field transplant experiment demonstrated that canopy cover had negative performance effects on both species. However, leopard frogs, which grow faster than wood frogs in open‐canopy ponds, were more strongly affected by closed‐canopy pond conditions. 3. Closed‐canopy ponds had lower temperature, dissolved oxygen (DO), and food nutritional quality as indicated by carbon‐to‐nitrogen ratio (C : N) analysis of field‐sampled food types, and of gut contents of transplanted larvae. 4. Laboratory experiments demonstrated that higher temperature and food quality but not DO substantially increased larval growth. However, only food quality increased growth rates of leopard frogs more than wood frogs. 5. The strong correlation of growth rates to gut content C : N in the field, and the similarity of growth curves as a function of resource quality in the field and laboratory, strongly suggest that resources are of primary importance in mediating intraspecific, and especially interspecific differences in performance across the canopy cover gradient.     

The influence of illness‐related variables,personal resources and context‐related factors on real‐life functioning of people with schizophrenia

In people suffering from schizophrenia, major areas of everyday life are impaired, including independent living, productive activities and social relationships. Enhanced understanding of factors that hinder real‐life functioning is vital for treatments to translate into more positive outcomes. The goal of the present study was to identify predictors of real‐life functioning in people with schizophrenia, and to assess their relative contribution. Based on previous literature and clinical experience, several factors were selected and grouped into three categories: illness‐related variables, personal resources and context‐related factors. Some of these variables were never investigated before in relationship with real‐life functioning. In 921 patients with schizophrenia living in the community, we found that variables relevant to the disease, personal resources and social context explain 53.8% of real‐life functioning variance in a structural equation model. Neurocognition exhibited the strongest, though indirect, association with real‐life functioning. Positive symptoms and disorganization, as well as avolition, proved to have significant direct and indirect effects, while depression had no significant association and poor emotional expression was only indirectly and weakly related to real‐life functioning. Availability of a disability pension and access to social and family incentives also showed a significant direct association with functioning. Social cognition, functional capacity, resilience, internalized stigma and engagement with mental health services served as mediators. The observed complex associations among investigated predictors, mediators and real‐life functioning strongly suggest that integrated and personalized programs should be provided as standard treatment to people with schizophrenia.     

大头茶属植物研究进展

大头茶属(Polyspora Sweet)为山茶科常绿树木,共50种,主要分布于南亚和东南亚地区。大头茶属植物均具有较高观赏价值,可作为热带和亚热带地区的园林绿化树种,部分种类兼具食用和药用价值。该文在对大头茶属种质资源和应用情况简要介绍的基础上,对其系统演化及分类、繁殖特征、生理特性、生态习性、育苗技术、化学成分及药理活性等方面的研究进展进行了较为详细的综述,提出了目前研究中存在的问题,并对今后的研究方向进行了展望,指出未来应扩大大头茶属的研究范围和种类,加强种质资源搜集、系统发育、遗传多样性等研究,重点关注大头茶属的引种栽培与种质创新,充分发掘其药用价值,开展临床转化和药物研制工作,可为合理开发利用野生大头茶属种质资源提供理论依据和研究思路。     

苎麻属植物资源基础研究进展

我国是栽培苎麻的原产国,拥有丰富的苎麻属植物资源.深化苎麻资源的研究对了解苎麻属植物的分类与进化以及苎麻品种改良等都具有重要意义.本文综述了苎麻属植物的起源分类与进化、细胞学、分子生物学以及苎麻资源研究标准与规范制定等基础性研究进展,并对苎麻资源的研究提出建议.     

27份花生种质资源的主成份分析及遗传距离测定

摘要：本文对27份花生种质资源的10个主要农艺性状表现进行了变异和主成份分析,结果表明：单株秕果数、单株结果数、主茎高与单株双仁果数变异系数较大;前4个主成份对变异的累计贡献率达84.98%。根据各种质资源的主成份值判断其表现特点,选出了综合性状比较理想的10份品种作为育种亲本。利用各种质资源的前4个主成份值计算各品种间的遗传距离,按遗传距离大小在D2=3.21水平下将27份种质资源聚类划分为6大类群,其中Ⅱ类群品种数最多(16份),该类群品种综合性状也表现较好,大多可为育种亲本利用或推广种植提供选择。     

中国粮食和农业植物遗传资源状况报告(Ⅱ)

10多年来,中国政府十分重视粮食和农业植物遗传资源的保护和可持续利用,并根据《粮食和农业植物遗传资源全球行动计划》20项优先领域,通过制定和完善相关的法律法规,加强了粮食和农业植物遗传资源的管理;通过培训和科普宣传,提高了公众意识;通过国际合作和协作网建设,实现了信息、人员和植物遗传资源的交流与交换;通过各种国家计划和项目的实施,建立和完善了植物遗传资源保护体系,实现了植物遗传资源的安全保存和可持续利用,为中国乃至世界植物育种和粮食安全发挥了较大作用。