植物钾营养性状的遗传潜力

钾是植物生长发育所必需的大量元素 ,是与氮、磷并列的植物营养的“三大要素”之一。不同植物种类或同种类植物的不同品种之间钾营养效率的差异非常显著 ,这为植物钾营养性状的遗传改良提供了科学依据。     

植物钾营养高效分子遗传机制

钾是植物生长发育所必需的矿质营养元素之一。不同种类植物的钾营养效率存在差异, 已有证据表明这种差异是受遗传基因控制的。植物细胞依靠细胞膜上的各种钾转运体和通道蛋白吸收和转运钾离子, 这些膜蛋白的活性调控是植物钾营养效率调控的关键和基础。本文对植物钾营养高效性状分子遗传机制以及相关基因的分子功能和调控机制的研究进展进行了简要评述, 并讨论了改善作物钾营养高效性状的可能途径。     

植物钾营养高效分子遗传机制

钾是植物生长发育所必需的矿质营养元素之一。不同种类植物的钾营养效率存在差异,已有证据表明这种差异是受遗传基因控制的。植物细胞依靠细胞膜上的各种钾转运体和通道蛋白吸收和转运钾离子,这些膜蛋白的活性调控是植物钾营养效率调控的关键和基础。本文对植物钾营养高效性状分子遗传机制以及相关基因的分子功能和调控机制的研究进展进行了简要评述,并讨论了改善作物钾营养高效性状的可能途径。     

植物体内的钠及其营养功能

众所周知高等植物所必需的营养元素有16种，但随着植物营养科学研究与分析化学技术的发展，在16种必需营养元素之外，近年来发现还有一类营养元素，适量条件下它们对一些植物的生长发育具有良好的促进作用，或作为某些植物在特定条件下所必需，但不是为所有的植物所必需，人们称之为“有益元素”，钠元素便是植物有益元素之一。一、植物体内销的含量通常植物内钠的平均含量大约是干物质总重的0．l％左右，是钾量的回／且比不同种类植物含销量变化很大，例如甜菜的含销量可达3％－4％，相当于钾的含量，甚至高于钾；不同种的牧草含钠量可在20…     

植物对钾营养的吸收、运转和胁迫反应的研究进展

钾营养研究是植物营养研究中的重要内容之一.对植物中钾的吸收和转运、钾转运系统、低钾胁迫和缺钾时的生理表现等方面做了详细的综述,并提出了解决钾肥供需矛盾的措施.     

外源钾水平对长春花生长和生物碱积累的影响

钾营养对于植物的生长发育具有重要作用,通过对长春花施以不同水平的外源钾,以探讨在不同浓度的钾素营养条件下,长春花生物量和生物碱的积累特点。结果表明,外源钾素营养水平的增加显著促进长春花的株高、根长、生物量积累,其中以10和15 mmol·L^-1浓度下的作用效果最显著。同时,外源的钾素营养水平提高还显著增加长春花的吲哚类生物碱含量,其中长春质碱的含量随着钾素营养浓度增大而增加;文多灵和长春碱随着钾素营养浓度增大都是先增加后减小,在15 mmol·L^-1浓度下达到最大值,过高的钾素营养不利于两者的合成。     

植物响应缺钾胁迫的机制及提高钾利用效率的策略

钾是植物体内含量最大的阳离子,在植物生长发育过程的诸多生理生化反应中起关键作用。缺钾会抑制植株根系的生长,使根冠比降低;同时阻碍光合产物的合成和向韧皮部转运,导致生物量下降。因此,提高植物钾营养的吸收转运和利用效率对于作物品种改良和增产具有重要的理论和生产实践意义。该文综述了植物响应低钾的生理机制和提高植物钾利用效率的四大策略,并对改善钾营养吸收利用以提高作物产量和品质进行了讨论及展望。     

植物钾离子通道AKT1的研究进展

植物生长发育过程钾具有很多重要的作用,植物吸收钾离子的重要途径中包含钾离子通道。近年来,已从同种植物的不同组织器官和多种植物中分离到多种钾离子通道基因,本文将从钾离子通道AKT1的结构、功能、调控机制以及其应用等四方面综述关于植物钾离子通道AKT1的研究进展,并对应用生物工程手段改良植物钾营养进行讨论。     

2,3,5-三碘苯甲酸(TIBA)对大豆开花的影响

植物从营养生长到繁殖过程的物质代谢问题,以及招致代谢类型改变的外在条件等均曾引起许多生理学家们的注意。Bolle-Jones(1954)研究营养水平对马铃薯开花的影响,发现当钾的供应水平高时,增加铁的供应,则延迟开花,减少每株花的数目;但当铁的供应水平低时,增加钾的供应,则每株花数亦随之增加。国外的许多研究工作曾指出植物生长素既可以诱导植物开花,也可以抑制开花,其对於植物开花的效应,则因植物的种类不同或施用的生长亲的浓度不同而异。Leopold and Thimann(1949)施用低浓度(0.01毫克/升)的萘乙酸(NAA)於大麦     

根分泌的有机酸对土壤磷和微量元素的活化作用

在养分胁迫下,尤其是缺磷条件下,许多植物可通过增加有机酸的分泌,作为其适应机制．讨论了营养胁迫条件下不同生态型植物根系分泌有机酸的种类,分析了不同生态型植物分泌的有机酸种类和数量之间的差异．结果表明,在缺磷条件下植物根系所分泌有机酸的种类和数量与它们所处的土壤环境关系密切．在营养胁迫条件下植物根系分泌的有机酸具有活化土壤磷、微量元素和缓解Ａｌ毒的功能;对有机酸活化土壤养分,解Ａｌ毒可能的作用机制进行了论述     

植物钾吸收基因及其遗传转化的研究进展

综述了近年来已分离和克隆的与植物钾离子吸收有关的基因及其在遗传转化方面的研究进展,对应用生物工程技术改良植物的钾营养性状进行了讨论。     

Theoretical and practical approaches to the genetic specificity of mineral nutrition of plants

Summary Mineral nutrition of plants is one of the most important factors controlling biomass production. However, the efficiency of utilizing certain elements of mineral nutrition in biomass production is highly related to the genetic specificity of plants. The present paper deals with problems and former results regarding plant mineral nutrition presented from the genetic aspects. Particular attention has been devoted to the increased efficiency of using both the natural fertility of soils and mineral fertilizers by creating and utilizing suitable cultivars and hybrids, increased efficiency of using mineral nutrients under certain ecological conditions, plant-specific role of microorganisms in enriching soil with nitrogen and soluble forms of other elements, role of genetic specificity of mineral nutrition in plants in solving the problems of environmental pollution, principles of evaluating the genetic specificity of mineral nutrition in plants, genotype features influencing uptake of mineral nutrients, criteria for evaluating the genetic specificity of mineral nutrition of plants, and also to the methods for selecting genotypes for specific soil types, and mineral nutrition.     

寄主钾营养对烟粉虱发育、存活和寄主选择的影响

为了探讨寄主钾营养对烟粉虱发育、存活和寄主选择的影响,设置了K0（0 mg/L）、K30（30 mg/L）、K60（60 mg/L）、K120（120 mg/L）和K240（240 mg/L）5种不同钾浓度,研究了烟粉虱在不同处理黄瓜上的发育历期、存活率、体形以及成虫的寄主选择。结果表明：在温度（26±1）℃,相对湿度80%±5%的条件下,取食不同钾营养水平黄瓜的烟粉虱在发育历期、存活率、体形上均有差异,其中在K240处理黄瓜上烟粉虱若虫发育最慢,从卵到成虫的时间最长,为21.4天,而在K60处理黄瓜上最快,为18.3天。在不同钾浓度处理寄主上从卵到成虫存活率以K30处理黄瓜上最高（84.7%）,其次依次为K60（83.8%）、K120（76.2%）、K0（71.4%）和K240（64.8%）。在体形上以K30处理黄瓜上最大,K240处理黄瓜上最小。寄主选择性试验结果表明,在温室条件下,烟粉虱成虫喜欢在K60处理黄瓜上取食和产卵。这些结果提示在一定范围内可以通过调节寄主钾营养状况来调控烟粉虱种群。     

Access and excess problems in plant nutrition

As plant nutrition issues are redefined by society, new applications emerge for a basic understanding of nutrient use efficiency in soil-plant processes to avoid excess on rich soils as commonly found in the temperate zone and make the best of it under access-limited conditions common in the tropics. The main challenge of plant nutrition may be to increase the width of the domain between the access and excess frontiers, rather than to define a single `economic optimum' point. Two approaches are discussed to widen this domain: the technical paradigm of precision farming and the ecological analogue approach based on filter functions and complementarity of components in mixed plant systems. Current understanding of plant nutrition, largely focused on monocultural situations, needs to be augmented by the interactions that occur in more complex systems, including agroforestry and intercropping as these may form part of the answer in both the excess and shortage type of situation. Simulations with the WaNuLCAS model to explore the concepts of a 'safety-net' for mobile nutrients by deep rooted plants suggested a limited but real opportunity to intercept nutrients on their way out of the system and thus increase nutrient use-efficiency at the system level. The impacts of rhizosphere modification to mobilize nutrients in mixed-species systems were shown to depend on the degree of synlocation of roots of the various plant components, as well as on the long-term replenishment of the nutrient resources accessed. In conclusion, the concepts and tools to help farmers navigate between the scylla of access and the charibdis of excess problems in plant nutrition certainly exist, but their use requires an appreciation of the site-specific interactions and various levels of internal regulation, rather than a reliance alone on genetic modification of plants aimed at transferring specific mechanisms out of context.     

Influence of nutrition on disease development caused by fungal pathogens: implications for plant disease control

A great deal of information is available in the literature on the effects of nutrition on disease development in plants and crops. However, much of this information is contradictory and although it is widely recognised that nutrition can influence disease in crops, limited progress has been made in the manipulation of crop nutrition to enhance disease control. Achieving this aim requires a sound understanding of the effects of fertilisation on nutrient levels and availability in crop tissues, and in turn, how the nutrient status of such tissues influences pathogen infection, colonisation and sporulation. Some of these details are known for a number of crop plants under controlled conditions, but very little of this type of information is available for crops under field conditions. This review focuses on nitrogen, sulphur, phosphorus, potassium and silicon, examines the availability of these nutrients in plant tissues to support pathogen growth and development, and reviews the effects of the different nutrients on disease development. The review also examines the potential for manipulating crop nutrition to enhance disease control in conventional and organic cropping systems.     

The role of ion channels in plant nutrition and prospects for their genetic manipulation

Ion channels can function in three physiological modes through their ability to: 1) accommodate osmotically significant fluxes over short periods; 2) propagate signals along or across membranes; 3) control the membrane potential. With respect to mineral nutrition it is via the control of the membrane potential that ion channels are probably most significant. In this paper the physiology and prospects for molecular biology of plant ion channels are discussed. It is concluded that identifying and altering the primary structures that determine functional characteristics of plant ion channel genes could result in changes in the transport characteristics of higher plants.     

珍稀濒危植物迁地保护策略中植物营养问题的探讨

营养缺乏、过量或不平衡都会直接导致植物生长繁殖障碍甚至死亡,通过改良土壤或补充矿质元素来解决这些问题是植物营养学研究的主要内容。这一学科的研究范围已经从传统人工生态系统发展到自然生态系统中。但总的来说,这一学科还没有真正渗透到珍稀濒危物种的迁地保护领域中来。中国各植物园目前正在开展大规模的珍稀濒危植物迁地保护工作,但人们都只重视了物种的引入,却忽视了它们在迁地保护过程中业已存在和可预见的生长繁殖障碍,对迁地保护植物的研究很少涉及其生长繁殖所需的营养条件。针对这一现状,本文提出了目前应开展的几项工作:(1)明确优先开展植物营养学研究的物种范围;(2)物种原产地土壤与植物化学元素背景值的分析;(3)迁地保护物种营养状况动态监测与营养诊断。该研究思路的提出,无论是从植物营养学与植物保育学的学科交叉角度,还是从珍稀濒危物种迁地保护保育策略的理论探索与解决实际问题的角度,都具有十分重要的意义。     

Secondary effects of potassium and nitrogen nutrition of rice: Change in microbial activity and iron reduction in the rhizosphere

Summary In solution culture experiments with rice the effects of different potassium applications and of various nitrogen sources on some criteria of microbial activity were studied. The following results have been obtained:The number of bacteria in the rhizosphere depends on the form of nitrogen available to the plants and the potassium nutritional state. With ammonium as a nitrogen source a greater number of bacteria is found in the rhizosphere than with nitrate. The interruption of potassium nutrition results in an increase in the total number of bacteria.In accordance with the different bacterial colonisation, the oxygen content in the nutrient solution with nitrate remains higher than with ammonium nutrition. With an increase in bacterial number after K interruption, a corresponding depression of the oxygen content in the nutrient solution can be noted. This is due to the higher respiration rate of the roots and the bacteria adhering to them in K-deficient plants.K deficiency consequently results in an increased concentration of reduced divalent iron in the nutrient solution.From the above results it follows that optimum potassium nutrition makes an essential contribution towards counteracting highly reducing conditions in paddy soils.