ABA对植物侧根发生的调节(综述)

本文概述侧根发生及其受ABA调控的研究进展.ABA通过抑制部分侧根起始基因的表达、抑制侧根分生组织的活化等调控侧根发生.氮水平和干旱胁迫抑制拟南芥侧根发育,ABA可以缓解这种抑制作用.ABA和生长素在侧根原基发生过程中相互作用,其作用机理较为复杂.     

侧根的发生及其激素调控

本文概述了侧根发生及其植物激素调控的研究进展。侧根的发生起源于特定的中柱 鞘细胞,其发生过程可简单地分为侧根发生的起始、侧根原基的形成、侧根分生组织的形成和活化等几个关键时期。参与侧根发生调控的植物激素主要是生长素,它影响到侧根发生过程的各个时期。茉莉酸对侧根的发生也有一定的调控作用。     

侧根的发生及其激素调控

本文概述了侧根发生及其植物激素调控的研究进展。侧根的发生起源于特定的中柱鞘细胞,其发生过程可简单地分为侧根发生的起始、侧根原基的形成、侧根分生组织的形成和活化等几个关键时期。参与侧根发生调控的植物激素主要是生长素,它影响到侧根发生过程的各个时期。茉莉酸对侧根的发生也有一定的调控作用。     

甲哌Weng对棉花幼苗侧根发生的诱导效应和机理研究

以陆地棉(Gossypium hirsutum L.)中棉所16和中棉所29号为试验材料,用垂直板培养法试验结果表明400 mg*L-1 甲哌钅翁(DPC)浸种处理显著促进棉花侧根发生,侧根原基发生量、发育速度和发生区长度都显著增加.去除侧根后,DPC增加侧根原基发生量和发育速度.在低温逆境情况下,DPC显著促进侧根发生,对增加抗低温能力有利.DPC处理提高了幼苗主根中部生长素、玉米素及其核苷含量,可能是诱导侧根发生的内在原因.     

生长素极性运输在水稻根发育中的作用

生长素极性运输(PAT)在植物生长发育尤其是极性发育和模式建成中起重要作用.采用2种PAT抑制剂TIBA(2,3,5-triiodobenzoic acid)和HFCA(9-hydroxyfluorene-9-carboxylic acid)处理水稻(Oryza sativa L. cv.Zhonghua)幼苗,结果表明:PAT影响水稻根发育包括主根的伸长、侧根的起始和伸长以及不定根的发育.PAT的抑制导致主根变短、侧根和不定根数目减少.外源附加生长素(NAA)可以部分恢复不定根的形成但不能恢复侧根的形成,表明在侧根和不定根的形成上可能具有不同的机制.切片结果表明,30μmol/TIBA处理后并不完全抑制侧根原基的形成,进一步研究表明生长素由胚芽鞘向基部的运输在水稻不定根的起始和伸长中起关键作用.     

生长素极性运输在水稻根发育中的作用

生长素极性运输(PAT)在植物生长发育尤其是极性发育和模式建成中起重要作用。采用2种PAT抑制剂TIBA(2,3,5-triiodobenzoic acid)和HFCA(9-hydroxyfluorene-9-carboxylic acid)处理水稻(Oryza sativa 1.cv．Zhonghua)幼苗,结果表明：PAT影响水稻根发育包括主根的伸长、侧根的起始和伸长以及不定根的发育。PAT的抑制导致主根变短、侧根和不定根数目减少。外源附加生长素(NAA)可以部分恢复不定根的形成但不能恢复侧根的形成,表明在侧根和不定根的形成上可能具有不同的机制。切片结果表明,30μmol／L TIBA处理后并不完全抑制侧根原基的形成,进一步研究表明生长素由胚芽鞘向基部的运输在水稻不定根的起始和伸长中起关键作用。     

生长素的信号传导与泛素化作用

生长素是植物体内一类非常重要的内源激素,它控制着植物的细胞伸长,顶端优势,侧根发生及维管束的发育等重要的生理过程。研究表明,生长素领带传导与泛素介导的某些蛋白质的降解过程密切相关。本文对生长素信号传导与泛素化作用的最新研究进展进行了综述。     

生长素信号对植物侧根发育的调控

植物根系是汲取水分、营养的重要器官,而侧根是植物根系重要的组成部分。生长素是调控侧根生长发育的核心因子。该文综述了生长素信号在直根系模式植物拟南芥以及须根系模式作物水稻中侧根发育调控中的研究进展,对生长素信号调控侧根起始模型、Aux/IAA介导的生长素信号对植物侧根发育调控这两个方面进行了阐述,并对拟南芥与水稻的侧根发育进行比较,最后对该研究领域进行了展望。     

ABI4调控侧根发育研究(综述)

生长素是调控植物侧根发育的关键植物激素,生长素运输载体PIN蛋白介导其极性分布。ABI4抑制生长素极性运输蛋白基因PIN1的表达,影响生长素的极性运输,抑制侧根形成。本文概述ABI4转录因子调控侧根发育的研究进展。     

生长素通过MAPK介导的超长链脂肪酸合成调控侧根发育

促分裂原活化蛋白激酶(MAPK)信号级联通路是真核生物中高度保守的重要信号系统, 通过激酶逐级磷酸化传递并放大上游信号, 进而调控细胞反应。MAPK信号通路不仅介导植物响应环境变化, 而且在调节植物生长发育过程中发挥重要作用。近期, 山东大学丁兆军课题组研究发现, 植物重要激素生长素能够通过激活MPK14调控下游ERF13的磷酸化, 进而影响超长链脂肪酸的合成并调控侧根发育。该研究从全新的角度解析了侧根起始的新机制, 并进一步证实生长素和古老的信号转导模块MAPKs相偶联的分子机制。侧根作为植物响应环境最重要的器官之一, MAPK信号通路在侧根发育过程中的功能解析可为阐明植物如何整合发育和环境信号提供新思路。     

Phaseolus vulgaris RbohB functions in lateral root development

Respiratory burst oxidase homologs (RBOHs) catalyze the reduction of oxygen to generate superoxide anion, a kind of reactive oxygen species (ROS). The ROS produced by RBOHs play essential roles in diverse processes, such as root hair development, stomata closure and signaling mechanisms in response to abiotic stimuli and during plant-pathogen interactions. Recently, we found that PvRbohB silencing in transgenic Phaseolus vulgaris roots had a negative impact on lateral root density. In this work, we show that the downregulation of PvRbohB affects both the growth and ROS levels in recently emerged lateral roots. In addition, we found that the PvRbohB promoter was activated during lateral root primordium initiation in the pericycle, and remained active throughout lateral root development. This study identifies RBOHs as potentially important players in lateral root development in P. vulgaris.     

脱落酸被土壤“掩盖”了的功能:调节根系构型形态建成

植物根系发育是一个重要的农艺性状。由于根系具有结构和生长模式简单、信号感受灵敏等,有可能成为研究植物发育可塑性的良好材料。通过分析脱落酸在主根、侧根和根毛的发生和生长中及根构型形成中的可能信号转导过程中的作用,提出未来研究应关注的科学问题。对ABA调控根系发育分子机制的探讨不仅有利于阐明如何调控根发育可塑性这一复杂和困难的生物学问题,而且对农业生产也极为重要。     

The Initiation and Development of Lateral Meristems in the Pea Root: I. THE EFFECT OF YOUNG AND OF MATURE TISSUE

The effect of.distinct regions of the root on the initiationof lateral root primordia and the emergence of lateral rootshas been studied, using segments of roots from sterile 2-daygerminated pea seedlings. It is shown that the removal of the basal region causes a decreasein the number of primordia formed in the remainder of the root.On the other hand, the removal of the apical region causes alarger number of primordia to be formed in the remaining tissuethan in the corresponding tissue of roots where the apical regionis retained. It is suggested that a factor or a complex of factorsinvolved in primordium initiation is translocated from the oldertissue towards the potential site of primordium initiation inthe young tissue which has just completed extension growth. The removal of the apical region of the root is also shown tostimulate lateral root emergence. It is suggested that a factoror complex of factors involved in the development of the primordiasubsequent to initiation moves within the root in a similarmanner to the factor or factors involved in initiation.     

Development correlations between roots in heterogeneous environments

Roots are known to respond to favourable nutrient conditions by increased initiation and growth of lateral roots. The problem studied here was to what extent does this local developmental response depend on the environments of other roots on the same plant. Such dependence could allow for an optimal allocation of resources required for root growth in unpredictable, heterogeneous soils. Pea seedlings (Pisum sativum var. arvense cv. Dun) were pruned and grown to have two equal root systems, each in an individual container. As expected, these roots responded by increased development to a wide range of nutrient solution concentrations. The local development of these roots, expressed by their dry weight, was a function of the relative rather than the absolute conditions in which they were grown: roots in a given environment developed more rapidly if other roots on the same plant were in poorer than if they were in richer nutrient conditions. The number of lateral initials doubled within 3d after the roots were exposed to optimal nutrient conditions, before any dry weight differences could be detected. This rapid root initiation was also a function of the conditions other roots of the same plant were in. These results mean that root development, and especially lateral root initiation, depends on the integrated effects of the local environment and the internal correlative relations between the roots.     

Seasonal development of loblolly pine lateral roots in response to stand density and fertilization

In 1989, two levels each of stand density and fertilization treatments were factorially established in a 9-year-old loblolly pine plantation on a P-deficient Gulf Coastal Plain site in Rapides Parish, Louisiana, USA. In 1995, a second thinning was conducted on the previously thinned plots and fertilizer was re-applied to the previously fertilized plots. The morphology of new long lateral roots was evaluated at 2-week intervals in five Plexiglas rhizotrons per plot of two replications. The overall objective of this study was to evaluate the seasonal initiation of six morphological categories of long lateral roots ( 2.5 cm in length) in response to stand density and fertilization. Lateral root development exhibited a seasonal pattern with the initiation of branched lateral roots predominantly occurring in spring and summer. The initiation of non-branched lateral roots occurred throughout the year regardless of season. Stand density did not affect lateral root morphological development. However, fertilization stimulated the initiation of branched lateral roots that were greater than 1 mm in diameter.     

Sites and regulation of auxin biosynthesis in Arabidopsis roots

Auxin has been shown to be important for many aspects of root development, including initiation and emergence of lateral roots, patterning of the root apical meristem, gravitropism, and root elongation. Auxin biosynthesis occurs in both aerial portions of the plant and in roots; thus, the auxin required for root development could come from either source, or both. To monitor putative internal sites of auxin synthesis in the root, a method for measuring indole-3-acetic acid (IAA) biosynthesis with tissue resolution was developed. We monitored IAA synthesis in 0.5- to 2-mm sections of Arabidopsis thaliana roots and were able to identify an important auxin source in the meristematic region of the primary root tip as well as in the tips of emerged lateral roots. Lower but significant synthesis capacity was observed in tissues upward from the tip, showing that the root contains multiple auxin sources. Root-localized IAA synthesis was diminished in a cyp79B2 cyp79B3 double knockout, suggesting an important role for Trp-dependent IAA synthesis pathways in the root. We present a model for how the primary root is supplied with auxin during early seedling development.     

Molecular mechanism of adventitious root formation in rice

Adventitious roots account for the majority of the rice root system and play an irreplaceable role in rice growth and development. Rice adventitious roots are formed by division of the innermost ground meristem cells in the central cylinder, and some lateral roots are observable in the adventitious root system. Multiple hormones have been implicated in the regulation of root development. Auxin is involved in the initiation of adventitious roots, whereas cytokinin inhibits adventitious root initiation, but promotes adventitious root elongation. Other phytohormones such as nitric oxide, ethylene, brassinosteroid, jasmonic acid and gibberellin may be also involved in regulating adventitious root initiation and development. Additionally, more than 600 root development related quantitative trait loci (QTLs) have been located by QTL analysis of root traits.