植物气孔发育及其调控研究

气孔是植物与外界进行气体交换的通道。植物通过调节表皮气孔的开闭、大小和数目来优化气体的通过量,从而适应自身的生存环境。最近的研究工作揭示了控制气孔发育的基本遗传途径,以及环境信号如何调控气孔发育的基本遗传途径。文章总结了控制植物气孔发育基本途径的分子基础以及外界环境因素(主要是光和二氧化碳)与激素信号对气孔发育的调控机制,并对将来本领域需要解决的几个问题提出了看法。     

植物气孔发育的分子调控机制

气孔是陆生植物表皮上可以调节的小孔,也是植物进行气体交换的主要通道。气孔不仅对植物的光合作用起着非常关键的作用,而且对全球的碳循环和水循环具有重要的影响。气孔分布和形态结构在单、双子叶植物间也有较大的差异,这些差异因植物种类不同影响着气孔发育的精细调控。本文综述了调控气孔前体细胞命运的分子网络、细胞极性分裂和表观遗传机制,归纳了外界环境信号通过与内源信号通路互作介导气孔发育的过程,提出了气孔发育基于多水平控制的气孔发育模型。     

昆虫变态发育的激素和营养调控研究进展与展望

变态发育是促进昆虫进化和多样性形成的重要因素之一。昆虫变态发育主要受到蜕皮激素和保幼激素的协同调控,通过信号通路诱导下游基因表达,保证蜕皮、组织重塑等生理过程的正确发生。除内在激素外,外在营养物质亦可通过营养信号影响激素信号进而控制变态发育进程。本文主要综述了近十年来我国科研工作者在昆虫变态发育的激素和营养调控机制研究方面所取得的突出成果,并对未来潜在的研究方向进行了展望,以期对我国的害虫防治和益虫利用研究提供理论指导。     

生长素调控植物气孔发育的研究进展

气孔是分布于植物表皮由保卫细胞围成的小孔, 是植物体与外界环境进行水分和气体交换的重要通道, 通过影响光合作用、蒸腾作用及一系列生物学过程来促进植物适应环境的变化。生长素是最早被发现的植物激素, 在植物生长发育中发挥重要作用。近年来的研究表明, 生长素通过载体蛋白-TIR1/AFB受体-AUXIN/IAA-ARFs信号通路, 调控STOMAGEN的表达; 之后, 经STOMAGEN-类LRR受体蛋白激酶ERf-MAPKs级联反应激酶-SPCH转录因子信号通路, 启动气孔的发育进程。EPF1、EPF2和类LRR受体蛋白激酶TMM不是该过程的必需元件。生长素对气孔的调控受光信号影响, 光信号通路组分E3泛素连接酶COP1位于MAPKs激酶的上游, 参与气孔的发育调控。     

植物气孔发育的分子遗传调控

气孔广泛存在于植物地上组织和器官的表皮,是植物与外界环境进行气体交换的主要门户,调节光合作用和蒸腾作用等生理活动.原表皮细胞经过一系列固定的分裂和分化,最终产生成熟气孔.在气孔发育过程中,bHLH转录因子调控气孔细胞的起始、扩增和分化,受体-配体、MAPK信号级联介导的细胞间通讯确保正确的气孔发育图式的形成,极性蛋白调节气孔细胞不均等分裂的方向.此外,植物激素和环境因子也影响气孔发育.这些因子共同构建出植物气孔发育的分子遗传调控网络.本文综述了该网络及其最新研究进展     

水稻叶倾角调控的分子机制研究进展

叶倾角发育是影响叶片直立程度的重要因素,而直立叶型是高产水稻株型的重要指标之一。本文综述了近年来有关水稻叶倾角基因功能鉴定和分子调控机制的研究进展。激素在水稻叶倾角发育中起主要调控作用,尤其以油菜素内酯、生长素和赤霉素三类激素的作用最大。调控过程涉及到激素的合成与信号途径,同时也存在激素间的相互作用和其他调控途径,表明水稻叶倾角的调控是一个涉及多基因共同作用和多条信号途径的复杂过程。植物激素合成基因表达异常或信号传导异常可导致叶枕近轴与远轴面细胞分裂与生长不平衡,进而改变叶倾角。     

细胞周期因子与植物根系发育

植物根系的发育是一个非常复杂且被精确调控的过程,受到多种信号的调控,其中对细胞分裂水平调控的研究已经成为细胞生物学研究的热点之一.文章介绍了植物细胞周期因子和植物根系发育相关的细胞周期调控机制以及根系细胞周期激素调节的研究进展.     

植物气孔发育机制研究进展

气孔是分布在植物表面的微孔, 是植物水分散失和与外界环境进行气体交换的门户。经过多年的研究, 气孔发育过程中重要调节因子陆续被发现。气孔复合体结构、发育起始模式以及在双子叶植物和单子叶植物中的分布都有较大差异。该文综述了双子叶植物拟南芥(Arabidopsis thaliana)气孔发育过程中调控因子、细胞极性分裂以及环境因子和植物激素调控气孔发育的机制; 还阐述了单子叶植物玉米(Zea mays)、二穗短柄草(Brachypodium distachyum)和水稻(Oryza sativa)气孔发育方面的研究进展, 并展望了气孔发育的研究方向。     

水稻衰老调控机制研究取得重要进展

正植物的衰老受发育年龄和体内信号因子精确调节。脱落酸(ABA)是植物五大激素之一,参与众多的生物学过程,如促进种子休眠、提高耐逆性、调节气孔开关、促进叶片衰老等。在植物衰老时,体内ABA含量急剧升高,外源ABA也可诱导叶片衰老,因此,ABA被认为是一重要的衰老促进激素。然而,水稻中ABA合成和信号传导相关基因的突变体并未表现出延迟衰老的表型。因此,人们一直困惑ABA是如何参与调控植物的衰老进程。     

干旱下植物气孔运动的调控

概述了植物气孔对大气干旱和土壤干旱的反应,认为植物气孔对大气干旱的反应并不是一种反馈机制;并就干旱条件下植物气孔运动的水力学和化学信号调控机制进行了简要论述,认为虽然化学信号调控干旱下气孔运动更为广泛,但ABA不是唯一的化学信号,水分关系影响了信号的产生、运转和气孔对信号的敏感性,干旱条件下水力学和化学信号共同调控着植物的气孔运动。     

Effect of brassinolide, alone and in concert with abscisic acid, on control of stomatal aperture and potassium currents of Vicia faba guard cell protoplasts

The essential role of brassinosteroids (BRs) in normal plant growth, development and physiology has been established by the analysis of biosynthesis and signal transduction mutants. Some of the BR-related mutants also display altered sensitivity to the phytohormone abscisic acid (ABA) suggesting that BRs normally counteract the effects of ABA on root growth, seed germination, and possibly stomatal movement. In this study, the effect of a specific BR, brassinolide (BL), on guard cell function of Vicia faba was examined alone and in conjunction with ABA. Unlike other described plant responses, BL did not oppose the effect of ABA in regulation of stomatal movement. On the contrary, BL modulated stomatal aperture by promoting stomatal closure and inhibiting stomatal opening, functions of this hormone that were previously undescribed. This study also demonstrated a role for plant steroidal hormones in ion channel regulation: BL inhibited inwardly rectifying K⁺ currents of V. faba guard cell protoplasts in a manner similar to ABA. In both stomatal movement assays and whole-cell patch clamp experiments, the effects of BL and ABA applied together were not additive, suggesting that these two hormones may function in interacting pathways to regulate stomatal apertures and guard cell physiology.     

One for All and All for One: Cross-Talk of Multiple Signals Controlling the Plant Phenotype

The plant hormone ethylene plays a pivotal role in steering various processes by regulating the biosynthesis, distribution, or signal transduction of other hormones. Ethylene also mediates the effects of other hormones. Similarly, hormones control the ethylene synthesis and signalling pathway. Eventually, integration of this network of signals leads to an appropriate morphological or biochemical response. Consequently, this cross-talk results in the characteristic plasticity associated with plant development. Here, the interplay of ethylene with other hormones is described for germination and seedling growth, stomatal control, and tissue elongation. The mechanisms by which this occurs are discussed in more detail.     

Hormonal Interactions and Stomatal Responses

Both environmental and hormonal factors and their interactions affect stomatal behavior. Methodologies for identifying hormonal interactions affecting stomatal function are reviewed. Although there is abundant evidence that abscisic acid (ABA) closes stomata, evidence that the other classical plant hormones (auxins, cytokinins, ethylene, gibberellins) in isolation alter stomatal response often comes from exogenous applications to detached epidermes and leaves, rather than correlation of endogenous concentrations with stomatal conductance (g_s). Evidence for hormonal interactions comes from isolated tissues with exogenous hormones supplied at nonphysiological concentrations, or from variation in stomatal response to xylem ABA concentration in planta. The roles of hormonal changes in causing stomatal closure following changes in soil environment are considered. Although soil drying induces multiple changes in xylem sap composition, analysis of stomatal responses suggests a dominant role for increased endogenous ABA concentrations and relatively little evidence of roles for other hormones. A similar picture emerges from studies of soil compaction. Although soil flooding decreases ABA export from the root system, there is some evidence that apoplastic ABA accumulation elicits stomatal closure. Stomatal closure following nitrogen deprivation does not appear to involve ABA and may provide a suitable experimental system to investigate roles for other hormones. The availability of mutant or transgenic lines with altered hormone homeostasis or sensitivity provides opportunities to screen for altered stomatal behavior in response to different environments, and may provide new evidence that hormonal interactions are important in the control of stomatal behavior.     

微生物帮助烟草抗旱的机理及其应用

干旱是中国烟草种植业面临的较为严重的非生物胁迫.很多与植物共生或联合的根际微生物能帮助植物避旱和耐旱.微生物能通过菌丝吸水并转运到植物,通过产生植物激素或改变植物内源激素的平衡来促进根发育和伸长,或诱导叶片关闭气孔,促进根吸水和减少叶片散失水分来避旱.微生物能通过调整不同激素介导的信号通路,诱导植物产生系统抗逆性,促进植物细胞产生渗透保护剂、抗氧化物和活性氧清除剂而耐旱.微生物还能帮助植物吸收营养,以支持植物在干旱胁迫下的代谢和生长.本文关注丛枝菌根真菌、模式内生真菌印度梨形孢和根际促植物生长细菌帮助烟草和番茄等植物抗旱的机理,探讨如何在烟草育苗和栽培中应用有益微生物来帮助烟草抗旱.     

Drawing the future: Stomatal response to CO2 levels

Gas exchange between the plant and the atmosphere is regulated by controlling both the stomatal density and the aperture of the stomatal pore. Environmental factors such as light, the level of atmospheric CO₂ and hormones regulate stomatal development and/or function. Because atmospheric CO₂ levels have been rising since the Industrial Revolution, and it is predicted that they will continue doing so in the future, an understanding of the CO₂ signalling mechanisms in the stomatal responses will help to know how plants were in the past and will allow predicting how they will respond to climate change in the near future. This article covers the recent knowledge of the CO₂ signalling mechanisms that regulate both stomatal function and development.Key words: Arabidopsis, CO₂, development, epidermis, gas exchange, leaf, patterning, stoma     

赤霉素作用机制研究进展

赤霉素是一种常见的植物激素,在高等植物的各个生长发育阶段都具有重要的调控作用.赤霉素与其他所有激素间都存在相互作用,其作用的方向和类型取决于组织器官、发育阶段以及环境条件,使赤霉素对植物生长发育的调控及其在不同器官中的生理功能不同.本文对近年来国内外关于赤霉素的信号传导、作用机制以及赤霉素与其他植物激素间的相互作用及其调控机理的研究进行综述,以探讨赤霉素信号应答的复杂网络体系.     

Elevated CO2 induces physiological, biochemical and structural changes in leaves of Arabidopsis thaliana

Leaves of Arabidopsis thaliana grown under elevated or ambient CO2 (700 or 370 micromol mol(-1), respectively) were examined for physiological, biochemical and structural changes. Stomatal characters, carbohydrate and mineral nutrient concentrations, leaf ultrastructure and plant hormone content were investigated using atomic absorption spectrophotometry, transmission electron microscopy and enzyme-linked immunosorbent assay (ELISA). Elevated CO2 reduced the stomatal density and stomatal index of leaves, and also reduced stomatal conductance and transpiration rate. Elevated CO2 increased chloroplast number, width and profile area, and starch grain size and number, but reduced the number of grana thylakoid membranes. Under elevated CO2, the concentrations of carbohydrates and plant hormones, with the exception of abscisic acid, increased whereas mineral nutrient concentrations declined. These results suggest that the changes in chloroplast ultrastructure may primarily be a consequence of increased starch accumulation. Accelerated A. thaliana growth and development in elevated CO2 could in part be attributed to increased foliar concentrations of plant hormones. The reductions in mineral nutrient concentrations may be a result of dilution by increased concentrations of carbohydrates and also of decreases in stomatal conductance and transpiration rate.     

植物激素在苔藓生长发育与逆境响应过程中的作用机制研究进展

植物激素是由植物自身代谢产生的一类从产生部位移动到作用部位发挥调控功能的微量小分子有机物质,在植物生长发育、响应环境胁迫过程中起到关键作用.苔藓植物作为早期登陆的非维管植物,处于陆生植物进化早期的阶段,具有许多不同于维管植物的形态和生理特征.大部分苔藓中普遍存在8种主要的植物激素及其衍生物(包括ABA、JA、ET、SA...     

植物细胞过氧化氢的测定方法

过氧化氢是重要的活性氧之一,激素等发育信号和胁迫刺激可以诱导细胞内H2O2的产生和积累,继而调控植物的气孔运动、生长发育、衰老和逆境应答等诸多生理过程。准确测定植物细胞内H2O2的含量及变化模式是系统研究H2O2信号转导及其生物学功能的一个关键技术。该文以拟南芥为实验材料,介绍了目前植物细胞H2O2的主要测定方法,包括激光共聚焦显微检测、紫外分光光度计检测和DAB组织染色,在此基础上比较分析了上述方法在灵敏度、检测范围、定量、成本以及耗时等方面的差异,为相关研究选择合适的H2O2检测技术提供参考。