高等植物对渗透胁迫的基因表达

干旱、低温、盐渍等环境条件严重限制植物的生长和作物的产量。通过分析植物对环境胁迫的基因表达，人们可以利用基因工程手段获得抗逆性强的作物新品种。本文从以下几个方面介绍有关植物对渗透胁迫的基因表达调控及基因工程的研究进展：（１）植物对渗透胁迫的生理生化反应；（２）渗透胁迫下植物ＬＥＡ基因的表达；（３）水分胁迫下ＡＢＡ对基因表达的调控；（４）耐渗透胁迫的植物基因工程。     

进口与国产PEG对拟南芥种子萌发和幼苗主根生长影响的比较

干旱是造成作物减产的主要原因,我国每年因干旱造成的粮食损失达300亿kg。目前全球干旱缺水的状况日益加剧,世界各国都加强了植物水分胁迫响应遗传机理和分子改良作物抗旱新品种培育的研究,我国也开展了作物抗旱节水分子机制的研究。在实验室内聚乙二醇（PEG）6000或者聚乙二醇（PEG）8000被认为是目前模拟水分胁迫最好的大分子化合物,     

作物生长对土壤水分变动的双重效应

阐述了植物对水分胁迫后复水的双重效应－－滞后作用和补偿效应。水分胁迫对植物造成的不利影响，可以通过复水完全或者部分补偿，这取决于水分胁迫的程度和胁迫持续时间。植物在水分胁迫后是否存在补偿效应是目前国际上生物学研究与争论的热点。从植物整体出发，利用对作物生长和水分关系已有的认识及作物生长对水分变动响应的2种效应，建立作物生长对水分经历反应的时间滞后模拟模型，是今后研究的一个重要方向。     

作物生长对土壤水分变动的双重效应

阐述了植物对水分胁迫后复水的双重响应－滞后作用和补偿效应。水分胁迫对植物造成的不利影响，可以通过复水完全或者部分补偿，这取决于水分胁迫的程度和胁迫持续时间。植物在水分胁迫后是否存在补偿效应是目前国际上生物学研究与争论的热点。从植物整体出发，利用对作物生长和水分关系已有的认识及作物生长对水分变动响应的２种效应，建立作物生长对水分经历反应的时间滞后模拟模型，是今后研究的一个重要方向。     

作物对水分胁迫的反应

阐述了作物水分胁迫的生理生化机制及水分胁迫对作物营养、生育及产量的影响,讨论了水分胁迫反应机制在节水农业和可持续农业发展研究中应用的可能性。     

作物对水分胁迫的反应

阐述了作物水分胁迫的生理生化机制及水分胁迫对作物营养、生育及产量的影响,讨论了水分胁迫反应机制在节水农业和可持续农业发展研究中应用的可能性。     

植物钾吸收转运基因的克隆与作物遗传改良

本文从分子水平对植物吸钾的生理机制、钾吸收转运基因的分离克隆、钾基因在植物生理中的作用及应用基因工程技术改良作物钾营养性状、培育钾高效品种等方面的研究进展作了较为系统的讨论。     

干旱条件下土壤中锌的有效性及与植物水分利用的关系

我国北方地区石灰性土壤上缺锌与干旱限制因子同时存在,影响作物生长和产量提高。本文综述了干旱胁迫影响土壤锌的有效性和植物对锌吸收利用的可能机制:土壤中锌不同形态间的转化与化学行为、根际土壤中锌的移动性、植物根系形态和生理反应、植物体内锌的运输以及植株对锌的需求等在水分胁迫下都可能发生变化。植物锌营养状况可能与植物气孔开闭、活性氧代谢和基因转录因子-锌指蛋白的形成等关系密切,从而影响植物对水分的吸收利用和对干旱胁迫的适应。     

全程与阶段性非充分灌溉条件下水稻的生长及部分生理反应

有关水分胁迫改变水稻生长形态、组织结构与生理代谢方面的研究已有不少报道，但试验结果间颇有差异。在以往水分胁迫的植物效应研究中，往往只讨论水分胁迫处理本身对试验结果的影响，较少涉及处理前水稻生长环境的影响。至今尚未见有作物对全程和阶段性非充分灌溉反应差异的试验报道。本研究拟通过作物体对水分胁迫较为敏感的叶片水分含量、叶绿素含量和丙二醛(MDA)含量、根系活力、叶片气孔阻抗和光合速率等指标进行测定，探讨抽穗后(即阶段性)与全程非充分灌溉影响水稻产量形成的差异及其生理机制，为发展水稻节水栽培技术提供理论依据。     

通过转基因手段改善作物产量性状

在世界范围内,目前的作物转基因研究主要针对于提高作物自身的抗逆性开展,而产量是一个较为复杂的农艺性状,受多种基因与环境的相互作用所控制.其中,光合作用、氮素同化、碳源分配、植株株型等生理过程是产量形成的基础.随着植物基因组测序工程的逐渐完善,控制上述生理过程的许多基因已被成功分离,并通过基因工程手段对其进行遗传修饰,最终获得了产量性状得以明显改善的转基因植物.虽然目前对于基因如何调控每个性状的机制尚未得到充分阐明,但是这些基因的获得及其增产功能的验证为作物的高产育种提供了一条全新的思路和一系列新方法.随着国家转基因生物新品种培育科技重大专项的实施,对功能基因的认识显得尤为重要,本文主要从影响作物产量形成的源、流、库、株型、氮素及水分利用率等几方面入手,对近10年来控制植物产量性状基因的相关研究进行了综述,期望为高产转基因作物新品种的培育提供一定的理论依据.     

Efficiency of screening criteria for drought tolerance in chickpea

Crop drought tolerance improvement is one of the most challenging objectives of plant breeding programs. Developing an efficient screening technology and access to genetic variation for the traits contributing toward drought tolerance are major steps in this direction. To go in this quest, an experiment was conducted under controlled condition in a greenhouse. Nine Kabuli chickpea genotypes were grown under well-watered condition (85–90% field capacity (FC)) until start of flowering. Then, the following water treatments were imposed: well-watered, intermediate (55–60% FC), and severe (25–30% FC) drought stress. Physiological and agronomical traits were compared under different water treatments. Drought stress and genotypes interaction was significant in all measured traits, indicating that various genotypes responded differently to drought stress. Among measured traits, electrolyte leakage, stomatal conductance, yield components, and harvest index exhibited the highest variations. Yield components and stomatal conductance showed maximum reduction under drought stress and in susceptible known genotype, ILC3279, reduction reached up to 95%. Principal component analysis indicated that relative water content, photochemical efficiency of photosystem II, and stomatal conductance are the physiological traits with greater contribution toward drought tolerance. Therefore, these traits should be evaluated ahead of many other traits in making selections for drought-tolerant chickpea genotypes.     

Morphophysiological Traits Imparting Salinity Tolerance in Maize (Zea mays L.) Hybrids under Saline Water Irrigation in Vertisols

Maize is categorized as a salt-sensitive crop and identification of fairly salt-tolerant lines is of paramount importance for increasing its production on saline soils. Experiments were conducted in randomized block design with three replications to identify maize accessions showing response to saline water irrigation, traits imparting tolerance, and their effect on yield attributes of maize. Significant variation was present among genotypes for specific leaf area (SLA), potassium (K) content, cob characteristics, yield, biomass, and harvest index. High amount of heritability with large genetic advance indicated the presence of additive gene action for traits like leaf water potential and leaf dry weight. Association analysis revealed high correlation between key traits and direct as well as positive effect of these traits on yield. Principal component analysis resolved three principal components, and high leaf area and water potential were conferring salt tolerance and thus higher yield.     

Improving agricultural water use efficiency by nutrient management in crop plants

Abstract

Improvement of agricultural water use efficiency is of major concern with drought problems being one of the most important factors limiting grain production worldwide. Effective management of water for crop production in water-scarce areas requires efficient approaches. Increasing crop water use efficiency and drought tolerance by genetic improvement and physiological regulation may be a means to achieve efficient and effective use of water. A limited water supply inhibits the photosynthesis of plants, causes changes of chlorophyll contents and components and damage to photosynthetic apparatus. It also inhibits photochemical activities and decreases the activities of enzymes in plants. Water stress is one of the important factors inhibiting the growth and photosynthetic abilities of plants through disturbing the balance between the production of reactive oxygen species and the antioxidant defence, causing accumulation of reactive oxygen species which induce oxidative stress to proteins, membrane lipids and other cellular components. A number of approaches are being used to enhance water use efficiency and to minimize the detrimental effect of water stress in crop plants. Proper plant nutrition is a good strategy to enhance water use efficiency and productivity in crop plants. Plant nutrients play a very important role in enhancing water use efficiency under limited water supply. In this paper we discuss the possible effective techniques to improve water use efficiency and some macronutrients (nitrogen, phosphorus, potassium, calcium and magnesium), micronutrients (zinc, boron, iron, manganese, molybdenum and chloride), and silicon (a beneficial nutrient) in detail to show how these nutrients play their role in enhancing water use efficiency in crop plant.     

丛枝菌根真菌与植物共生影响植物水分状态的研究进展

丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)能与宿主植物形成共生体,广泛存在于陆地生态系统中。大量研究表明,不同水分条件下,植物通过接种AMF比未接种AMF的植物具有更强的水分吸收能力和更高的水分利用效率。在干旱、盐胁迫下,接种AMF能有效提高宿主植物的耐旱性与耐盐性。本文综述了不同水分条件下,与植物共生的AMF通过扩大植物根系吸收面积、改善根系结构,增强植物根系吸收水分能力的相关研究进展。土壤中根外菌丝网络的形成,不但为植物增加了水分吸收途径(菌根途径),还通过改善植物体内的矿质营养来调节植物对水分的吸收,进而影响植物的水分吸收状况；不同水分条件下,根系被AMF侵染后植物的光合作用、蒸腾作用以及气孔导度都得到增强,植物蒸腾作用的增强能够直接有效的提升植物的蒸腾拉力,因此植物对水分的吸收能力得以提升。同时,被AMF侵染的植物的水分利用率、蒸腾速率以及净光合速率得以提升从而提高了植物的水分利用能力。进一步总结了缺水胁迫(干旱胁迫、盐胁迫)严重影响植物体内的水分状况,通过接种AMF可以有效调节植物在缺水胁迫下植物体内渗透调节物质的含量、抗氧化酶的活性,平衡植物体内离子平衡,提升植物光合、蒸腾作用水平,从而提高植物的耐胁迫能力。本文通过综述不同水分条件下,接种AMF对植物的影响及机制,期望为未来新型菌剂的研发与菌根互作对植物水分状况的改善提供支撑。     

植物非生物逆境相关锌指蛋白基因的研究进展

植物能够适应多种逆境主要是通过改变其基因表达和代谢途径来实现的,因此研究这些基因表达和功能对提高植物耐逆性具有重要意义。锌指蛋白是一类具有手指状结构域的转录因子,这种结构域由锌离子与多个半胱氨酸和(或)组氨酸组成,锌离子在稳定其结构和发挥调控功能方面具有关键作用。植物锌指蛋白在植物耐逆性方面具有重要作用。本文综述了近几年来从拟南芥(Arabidopsis thaliana)、水稻(Oryza sativa)、小麦(Triticum aestivum)、番茄(Solanum lycopersicum)等植物中克隆的与非生物逆境相关锌指蛋白基因的研究成果,重点阐述了其基因表达部位、受逆境诱导情况及转基因植株的耐逆性等。目前的研究结果表明锌指蛋白能够调控耐逆相关基因的表达,在植物逆境代谢中发挥重要作用,因此可以利用锌指蛋白基因进行作物耐逆性的遗传改良,提高作物的耐逆能力。     

The effect of cobalt stress on growth and physiological traits and its association with cobalt accumulation in barley genotypes differing in cobalt tolerance

Cobalt (Co) is beneficial for legume plants and not an essential element for most plants. There is no sufficient information about the effect of Co stress on barley growth. The current experiment was carried out to investigate the effects of different Co levels (25, 50, 75, and 100 µM) on growth and physiological traits of three barley genotypes (B325, J36, and B340) differing in Co tolerance. The results showed that Co stress inhibited plant growth, decreased chlorophyll content and photosynthetic rate, and enhanced oxidative stress. However, the effects differed among genotypes, with B325 and B340 being the most and the least affected, respectively. Co stress caused decrease and increase of manganese (Mn) and phosphorus (P) concentrations in both roots and shoots, respectively; iron (Fe) concentration had little change in shoots and a significant decrease in roots. The current results showed a close association of Co tolerance and its accumulation in plant tissues.     

水稻OsGPDH1的克隆与功能鉴定

为了解水稻甘油-3-磷酸脱氢酶基因在水稻抗逆性中的作用,本研究从水稻品种日本晴中克隆了1个编码甘油-3-磷酸脱氢酶的基因,命名为OsGPDH1,该基因编码的蛋白酶具有NAD(P)+结合域和脱氢酶域,且这2个结构域在植物中高度保守。构建过表达OsGPDH1基因载体转化水稻得到转基因植株,RT-qPCR分析表明,OsGPDH1基因在水稻孕穗期的叶、幼穗、茎、节、叶鞘中均有表达,说明该基因参与了水稻的生长发育过程。OsGPDH1基因也受到PEG6000、高盐、双氧水等逆境和甲基茉莉酸(mJA)、水杨酸(SA)等激素诱导表达,且诱导12h后,OsGPDH1的表达量达到最高水平,但对脱落酸(ABA)不敏感。盐胁迫下的发芽试验表明,过表达转基因水稻的发芽率高于野生型,说明OsGPDH1基因表达量的提高可增强转基因植株对盐胁迫的耐受性。对过表达OsGPDH1的转基因水稻进行苗期20%PEG6000胁迫处理后,转基因水稻的成活率显著高于野生型,说明OsGPDH1基因过表达可提高水稻苗期抗旱能力。本研究初步证明了OsGPDH1水稻抗盐胁迫和渗透胁迫的重要作用,为培育抗性转基因水稻新品种提供了新的基因资源。     

Variation and Segregation for Rachis Fragility in Spelt Wheat, Triticum Spelta L.

Spelt wheat, Triticum spelta L., has been proved to be rich-sources of useful genes for tolerance to biotic and abiotic stress, and grain quality. But this crop plant has some undesirable traits including glume tenacity and brittle rachis. Free-threshing and reduced fragility of rachis are very important traits for cultivation. The objectives in the present study were to investigate genetic variation of rachis fragility in a wide range of spelt accessions, to examine its genetic segregation pattern, and to clarify if rachis fragility is associated with dosage of chromosome 5A in aneuploid lines of bread wheat. The results demonstrated that spelt germplasm contains a wide range of rachis toughness, and thus selection of spelt wheat with desirable characteristics combined with an appropriate level of tough rachis would be possible. Spike morphology in the F₂ plants was segregated into the three types, square-headed, speltoid, and compactoid. The F₂ plants with compactoid spikes had the most brittle rachis, followed by the speltoid and square-headed spike F₂ plants. Rachis fragility in bread wheat also had genetic variation and was associated with dosage of chromosome 5A.     

植物耐铝机理研究进展

铝毒是酸性土壤上作物生产的主要限制因子,植物耐铝机理以及与耐铝有关基因的研究是近十多年来研究的热点。本文对植物耐铝的生理、遗传及分子机理的研究进展作了综述。明确了目前取得的突破性进展已使通过植物遗传育种及生物技术手段提高粮食作物耐铝性成为可能;同时,本文对今后的研究方向作了简要的讨论。     

转碱蓬SsNHX1基因烟草的耐盐抗旱性研究

烟草是重要的模式植物和经济作物,盐害和干旱两种环境因子对其生长发育、产量和品质都危害很大。为了提高烟草的耐盐抗旱性,本研究利用农杆菌介导的遗传转化法在烟草中过量表达了碱蓬液泡膜Na~+/H~+逆向转运基因SsNHX1,对转基因烟草的耐盐及抗旱性进行表型鉴定和各项生化指标的检测,以期得到耐盐抗旱表性良好的SsNHX1转基因烟草。表型分析发现,SsNHX1基因过表达株系L1和L5的抗盐能力比野生型显著提高,表现为盐胁迫条件下仍能保持旺盛的生长且根系的伸长未受抑制。SsNHX1过表达株系在叶片和根系中积累了更多的Na~+和K~+,同时Na~+含量增长速率较快,而K~+含量降低速率较缓,并可维持较高的叶片相对含水量和叶绿素含量,及较低的丙二醛含量和相对电导率。干旱胁迫发现,过表达株系受干旱胁迫程度更小,并在复水后迅速恢复正常生长。同时,过表达株系的丙二醛含量和相对电导率显著低于野生型,且维持了较高的叶片相对含水量及叶绿素含量。这些结果说明SsNHX1基因在烟草中过量表达后,降低了盐胁迫和干旱胁迫对烟草根系及细胞膜的损伤,并通过调节离子含量、降低细胞的渗透势,维持了叶片较高的相对含水量和叶绿素含量,最终提高了烟草的抗盐和抗旱性。