干旱条件下植物生长适应策略研究进展

受全球气候变化和人类活动的影响,干旱环境缺水现状正越来越严重,干旱区正在扩散。如何抑制这种蔓延趋势,逐步改善干旱区环境是当前亟待解决的全球性难题。基于多年来对干旱条件下植物物候节律、形态生长特性和资源利用策略等植物生长适应机制以及植被调控的研究结论,提出在今后的理论研究或植被实践中加强干旱条件下植物物候特征及其生理机制、全球气候变化下干旱环境植物的生长适应策略响应和以生长适应机制为基础的干旱环境植被调控实践等方面的研究,以通过深入了解干旱条件下植物的生长适应策略及其机制,指导干旱地区的植被实践,遏止干旱环境不断恶化的趋势。     

植物硫苷-黑芥子酶系统对环境胁迫的响应

硫苷-黑芥子酶系统是植物中一种特有的底物酶系统,其水解产物具有高度生物活性,该系统对植物的生长发育、生长素微调以及植物的防御保护等均有重要意义.目前对植物硫苷-黑芥子酶系统对环境胁迫的响应的研究多为对硫苷的研究,而对系统相关物质研究较少.本文对硫苷-黑芥子酶系统做了简单介绍,并对植物硫苷-黑芥子酶系统对病虫害和酸雨、水、温度、盐、重金属胁迫下的响应进行了综述.     

盐胁迫对植物的影响及植物的抗盐机理

盐是影响植物生长和产量的主要环境因子之一,根据国内外最新的研究资料,从盐胁迫对植物的生长、水分关系、叶片解剖学、光和色素及蛋白、脂类、离子水平、抗氧化酶及抗氧化剂、氮素代谢、苹果酸盐代谢、叶绿体超微结构的影响,及影响光合作用的机制等方面入手,对植物盐胁迫研究现状及进展情况进行了综述,旨在为开展植物抗盐机理研究、选育培育耐盐植物新品种提供依据。     

污染胁迫下的蛋白质组学研究

近年来,以双向电泳技术、生物质谱和生物信息学为核心的蛋白质组学技术飞速发展,其大规模高通量的特点,使得这项技术逐渐在环境科学领域,尤其是对污染胁迫下差异蛋白表达和污染物特异性的生物标志物的筛选研究中得到了广泛的应用。本文简要介绍了蛋白质组学的基本概念和技术方法,对蛋白质组学在微生物、植物和动物对于无机污染物和有机污染物胁迫的响应机制和分子生物标志物探究等方面的研究进展进行了概述,并对蛋白质组学技术今后在生态环境领域的需求、应用与发展进行了展望。     

干热河谷不同岩土组成坡地的降水入渗与林木生长

坡地对降水的入渗能力是决定干热河谷坡地土壤水分条件和林木生长的重要因素, 坡地入渗能力低是造成干热河谷土壤干旱的主要原因之一. 由于岩土孔隙状况的差异, 不同岩土组成坡地的入渗能力差异较大. 片岩坡地入渗速率为1.40～8.67 mm/min, 砂砾层坡地为6.33 mm/min, 砾石层坡地为0.69～2.20 mm/min, 轻度侵蚀泥岩坡地为0.6～1.3 mm/min, 强度侵蚀泥岩坡地为0.03～0.63 mm/min. 泥岩坡地土体黏重板结, 入渗能力弱, 天然降水入渗少, 对土壤水分的有效补充较少. 在干旱季节土体极其干旱, 林木生长停止, 甚至受到干旱的生理伤害枯死, 林分生产力低, 极难恢复森林植被. 片岩坡地、砾石层坡地、砂砾层坡地等石质山地土体裂隙发育, 入渗能力强, 天然降水入渗多, 对土体水分的有效补充较多, 在干旱季节岩土深层有少量有效储水供林木吸收利用, 维持其正常生理活动的水分需要, 林木生长较泥岩坡地上的林木生长快, 林分生产力高. 干热河谷的植被恢复应针对不同坡地类型生境的土壤水分条件, 主要依靠优势生活型植物种类, 进行乔-灌-草不同生活型植物类型的合理配置, 建立起植被与生境土壤水分条件的群落生态关系, 方能达到成功的目的. 另一方面, 增加降水入渗的造林整地措施和集流入渗的工程措施是干热河谷植被恢复的主要技术关键之一.     

小麦转基因研究现状及展望

自二十世纪八十年代开始研究转基因植物以来，小麦作为世界主要粮食来源，其转基因遗传改良受到科学家的广泛关注。目前国内外已有近200例外源基因，主要是抗除草剂类基因、抗病虫基因、品质基因、抗旱耐盐等抗逆基因、雄性不育类基因等，通过基因枪法、农杆菌介导法、花粉管通道法等技术转入小麦的报道。从转单基因到进行多基因组装，从改良各种生物胁迫和非生物胁迫的抗逆性，到改良品质、高产等生理和农艺性状，是未来转基因小麦的研究方向。本文就近二十几年来转基因小麦研究进展及存在问题进行了全面系统的综述和探讨。     

横断山区干旱河谷研究现状和发展方向

干旱河谷及其所在的横断山区是独特的自然、气候和地理单元，是我国民族多样性、文化多样性、环境异质性以及生物多样性最为丰富的地区，少数民族分布最为集中的地区之一，也是西南经济最为落后、交通偏远、地质灾害最为严重的区域。干旱河谷以其较好的光热等条件成为整个横断山区人口和城镇分布集中的核心地带，但是由于干旱河谷脆弱的生态系统和特殊的交错带分布格局，决定了干旱河谷具有低阈值生态安全和高风险生态退化的特点。近几十年来在干旱河谷治理方面做了大量工作，在个别区域生态恢复方面取得了一些进展，农林可持续经营模式受到关注，经济资源植物引种和开发日益受到重视，基于地方特色的产业逐步得以兴起并取得初步成效。但从整个区域来看，干旱河谷研究方面还存在研究区域过分集中、人地关系研究缺乏、生态恢复模式过于单一等问题，加上人口和经济发展的压力，干旱河谷治理和开发的选择有限，使整个干旱河谷区次生干旱化仍然在发展中，生态环境退化状况仍在加剧，水土流失严重威胁本地和下游安全，资源和环境压力日益增加。干旱河谷进一步的研究应立足发展的需要，着重从干旱河谷本身演变机制的研究、全球变化背景下干旱河谷响应特征及规律、干旱河谷人地关系与上下游利益协同关系、干旱河谷景观结构和功能演变规律方面入手，在此基础上区分干旱河谷的自然和人为过程，全面制定整个干旱河谷区域的生态环境治理、经济与资源环境可持续战略，实现整个干旱河谷区域经济和环境持续协调发展。     

水生高等植物化感抑藻作用研究

本文从四类水生植物所产生的化感物质,以及化感抑制机制等方面对化感控藻技术进行了评述。研究发现环境因素,如光照,营养胁迫等会显著影响化感作用效果。     

由臭氧层衰竭导致的UV—B辐射增加对陆生植物的影响

本文回顾了近年来UV－B辐射对陆地植物及其环境影响的若干研究结果。从UV－B辐射对生物大分子和细胞的影响开始,着重讨论了对植物细胞的,继而探讨了UV－B辐射对人工生态系统的农作物和树木,以及在自然生态系统中的植物影响,然后讨论了UV－B辐射增强与另外的非生物因素相结合时对植物的影响,以及UV－B辐射对植物枯落物分解的影响,最后还论及了今后的研究趋势。     

淹没状态下河道植物偏斜高度与糙率的关系

利用室内变坡水槽,模拟了复式河道滩地3种植物对漫滩水流的干扰作用,并借助声学多普勒测速仪（ADV）施测了不同垂线、不同测点的瞬时流速,计算了不同条件下的河道糙率。基于水动力及植物柔性变形分析,建立了淹没状态下的植物河道糙率计算的基本关系,反映出糙率值不仅与水流动力条件有关,还与植物类型、淹没高度、布置及其自身力学性能有关,同时,利用试验资料及理论分析成果,进一步获取了植物河道的附加糙率值,借此分析与评价河道植物对水流阻力的影响程度。     

基因工程创造植物雄性不育研究进展

基因工程是创造植物雄性不育的新途径，具有很多传统方法不具备的优点。综述了基因工程创造雄性不育的机制及近年来的进展。     

植被因子对水土流失的影响

通过对国内外研究的总结以及植被对水土流失影响机理的分析得出,植被对水土流失有抑制的作用.在对水土流失进行预测和评价的过程中,作为诸多影响因子之一的植被因子,不论是在小尺度的试验研究中还是借助“3S”技术的大尺度研究中都是不可忽视的.大尺度研究所涉及的各种模型中,USLE模型及其各种修正形式是一种被广泛接受和应用的有效工具。     

Diversity, regulation, and genetic manipulation of plant mono- and sesquiterpenoid biosynthesis

Among plant secondary metabolites, terpenoids are the most abundant and structurally diverse group. In addition to their important roles in pollinator attraction and direct and indirect plant defense, terpenoids are also commercially valuable due to their broad applications in the cosmetic, food, and pharmaceutical industries. Because of their functional versatility and wide distribution, great efforts have been made to decipher terpenoid biosynthetic pathways, to investigate the molecular mechanism determining their structural diversity, and to understand their biosynthetic regulation. Recent progress on the manipulation of terpenoid production in transgenic plants not only holds considerable promise for improving various plant traits and crop protection but also increases our understanding of the significance of terpenoid metabolites in mediating plant-environment interactions.     

MAP kinases in plant signal transduction

Mitogen-activated protein kinase (MAPK) pathways are modules involved in the transduction of extracellular signals to intracellular targets in all eukaryotes. Distinct MAPK pathways are regulated by different extracellular stimuli and are implicated in a wide variety of biological processes. In plants there is evidence for MAPKs playing a role in the signaling of abiotic stresses, pathogens and plant hormones. The large number and divergence of plant MAPKs indicates that this ancient mechanism of bioinformatics is extensively used in plants and may provide a new molecular handle on old questions.     

γ-Aminobutyric acid (GABA) signalling in plants

The role of γ-aminobutyric acid (GABA) as a signal in animals has been documented for over 60 years. In contrast, evidence that GABA is a signal in plants has only emerged in the last 15 years, and it was not until last year that a mechanism by which this could occur was identified—a plant ‘GABA receptor’ that inhibits anion passage through the aluminium-activated malate transporter family of proteins (ALMTs). ALMTs are multigenic, expressed in different organs and present on different membranes. We propose GABA regulation of ALMT activity could function as a signal that modulates plant growth, development, and stress response. In this review, we compare and contrast the plant ‘GABA receptor’ with mammalian GABA_A receptors in terms of their molecular identity, predicted topology, mode of action, and signalling roles. We also explore the implications of the discovery that GABA modulates anion flux in plants, its role in signal transduction for the regulation of plant physiology, and predict the possibility that there are other GABA interaction sites in the N termini of ALMT proteins through in silico evolutionary coupling analysis; we also explore the potential interactions between GABA and other signalling molecules.     

The spread of Tobacco mosaic virus infection: insights into the cellular mechanism of RNA transport

Interactions of plant cells with pathogens or other biotic or abiotic environmental factors can give rise to systemic defense responses that rely upon the cell-to-cell and systemic transport of specific signals. A novel type of systemic signaling was revealed by recent evidence indicating the existence of RNA species that travel cell to cell and through the vasculature. The most compelling evidence for intercellular and systemic transport of RNA in plants is provided by viroids and viruses that apparently use the endogenous transport machinery to spread infection. The cell to cell movement of plant viruses occurs through small pores in the cell wall known as plasmodesmata and depends on virus-encoded 'movement proteins'. This review summarizes current knowledge of Tobacco mosaic virus infection with emphasis on the mechanism by which this virus targets its RNA genome from sites of replication to plasmodesmata to achieve intercellular spread.     

Plant thionins – the structural perspective

Thionins belong to a rapidly growing family of biologically active peptides in the plant kingdom. Thionins are small (∼5 kDA), cysteine-rich peptides with toxic and antimicrobial properties. They show a broad cellular toxicity against wide range of organisms and eukaryotic cell lines; while possessing some selectivity. Thionins are believed to be involved in protection against plant pathogens, including bacteria and fungi, by working directly at the membrane. The direct mechanism of action is still surrounded by controversy. Here the results of structural studies are reviewed and confronted with recent results of biophysical studies aimed at defining the function of thionins. The proposed toxicity mechanisms are reviewed and the attempt to reconcile competing hypotheses with a wealth of structural and functional studies is made. Received 3 December 2005; received after revision 6 February 2006; accepted 18 March 2006     

化感活性物质影响种子萌发作用机理的研究进展

化感作用由于其独特的生物学特性而受到广泛关注,并逐渐成为近年来的研究热点。然而目前多数的化感作用研究关注于化感物质对幼苗生长的影响以及化感物质的分离、鉴定、提纯,而对化感物质影响植物种子萌发的作用机理缺乏足够的重视。本文主要论述了化感作用的概念、发展以及化感物质降低种子萌发率、改变激素平衡、破坏生物膜结构、影响种子呼吸代谢等一系列生理活动的作用机理。最后对今后化感作用的研究重点进行展望,强调应着重进行化感物质作用机理的精确研究,从分子、基因水平进行探讨。     

5-Thio-d-glucose:o-diphenoloxidase inhibition as its mechanism of action

Summary 5-Thio-d-glucose completely inhibitedo-diphenoloxidase from animal as well as plant sources. It has been reported that thioglucose suppresses spermatogenesis in mice and also insect metamorphosis, probably through inhibition of glucose transport. Inhibition ofo-diphenoloxidase (which is active in spermatozoa and insect larvae) is suggested as an alternative mechanism of action of thioglucose.