激素对水稻分蘖芽生长和分蘖相关基因表达的调控效应

以水稻品种‘南粳44＇为材料,研究了植物激素对水稻分蘖芽生长及OsTB1、OsD3、OsD10和OsD27等基因表达的调控。结果表明,水稻分蘖芽生长的调控至少存在两条途径,一条通过调控分蘖芽中CTK含量进而调控OsTB1等基因表达来实现,另一条通过调控OsD3、OsD10和OsD27等系列基因表达来实现。外源IAA和GA_3对水稻分蘖芽生长的调控是通过这两条途径共同实现的。     

氮高效水稻种质资源筛选的初步研究

采用在遮雨网室盆栽和不同施氮处理对1107份水稻种质资源不同生长时期的苗高、分蘖数和干物重等性状进行了研究.结果表明最高分蘖期相对干物重与不同时期相对苗高和相对分蘖数呈极显著正相关.不同时期相对苗高与相对分蘖数之间亦呈显著或极显著正相关.相对分蘖数、相对苗高和相对干物重在水稻种质资源中存在较大的变异,分蘖数可作为氮高效资源筛选的形态指标.通过比较5个时期苗高和分蘖数的相对生长量及最高分蘖期干物重的相对含量共11个指标,初步筛选出14份氮高效资源.     

生活污水尾水灌溉对麦秸还田水稻幼苗及土壤环境的影响

通过盆栽试验研究了麦秸还田下生活污水尾水灌溉对水稻幼苗和土壤环境的影响.测定了不同处理水稻幼苗根系形态、根系活力、分蘖、株高、干物质累积量、土壤亚铁、有机酸、酶活性.结果表明: 与自来水灌溉相比,不施化肥氮时,生活污水尾水灌溉显著提高了水稻移栽后41 d的分蘖数和根系活力;正常施氮肥时,生活污水尾水灌溉显著促进了水稻根系和植株生长,根长、根表面积、根体积、根系活力、水稻分蘖数和干物质累积量均显著高于自来水灌溉处理.生活污水尾水灌溉处理显著降低了土壤Fe²⁺和有机酸含量,土壤脲酶、过氧化氢酶活性等显著提高.生活污水尾水灌溉和施氮耦合能有效缓解秸秆还田初期对水稻幼苗生长的不利影响,改善水稻生长状况,提升土壤肥力和质量.     

李家洋院士等在水稻分蘖分子机制研究中再次取得重大进展

水稻的分蘖是决定产量的一个重要农艺性状。适当的分蘖数目直接决定水稻的产量。水稻的分蘖不仅是直接调控产量的一个关键农艺性状,同时也是在植物生物学中决定株型建成的一个核心科学问题。在过去十余年,植物基因组学国家重点实验室的李家洋院士及其合作者对水稻分蘖的调控机制进行了系统深入研究。     

水稻主茎与分蘖间的物质运输

本试验借助放射性同位素C~(14)、P~(32)从地上部和地下部分研究了水稻各生育期(分蘖期、抽穗期、乳熟期) 主茎与分蘖间同化物运转的规律,所得结果如下: 1.水稻植株在不同生育期主茎与分蘖间同化物的运转各有特点,分蘖期主茎叶片的同化物和根部吸收的P~(32)均可流向分蘖内,抽穗至乳熟期同化物极少(几乎没有)流入分蘖。分蘖中的物质在分蘖期亦流入主茎;抽穗期同化物则极少流入主茎,乳熟期光合产物流入主茎的量显著增加。 2.分蘖期主茎叶片光合产物流入分蘖的量比分蘖流入主茎的量多16.47%;主茎根系所吸收的P~(32)流入分蘖的量比分蘖流入主茎的量少12.87%。主茎与分蘖地上部与地下部物质相互运转差别直到抽穗期物质相互运转极少的情况下仍然存在。 3.主茎与分蘖间同化物运转与植株各生育期光合产物的积累,各器官对物质的需要,养分(C~(14),P~(32))进入植株体内的途径不同有着密切关系,有自主性,也有相关性。 4.试验征明:水稻植株内养分能互相协调成一个完整的有机联系,看来分蘖植株对水稻体内营养物质有调节的良好影响。特别应当指出的是乳熟期分蘖植株竟有1/3的光合产物转向主茎穗部积极参与主茎结实器官形成,这无疑地对增加主穗重起着有利作用。     

水稻OsTB1基因的结构及其表达分析

TCP基因是一类植物中新发现的、可能具有转录因子活性的基因家族,成员包括金鱼草的Cyclodiea (Cyc)、玉米的Teosinte Branched1 (TB1)以及水稻中的PCF1、PCF2等.玉米的TB1基因有维持玉米顶端优势的作用,与分蘖的发生密切相关;水稻和玉米同属禾本科,在发育的过程中都有分蘖的发生.通过筛选水稻的基因组文库,得到了水稻中的一个TB1同源基因Oryza sativa Teosinte Branched1 (OsTB1).该基因不含内含子,基因编码一个长度为388个氨基酸的蛋白,在氨基酸水平上与TB1的同源性为70%,含有保守的TCP区和R区,是属于TCP基因家族的一个成员.RT-PCR和mRNA原位杂交分析结果表明,OsTB1在水稻的侧芽中有很强的表达,在花序中有较弱的表达.以上结果显示该基因可能在水稻侧芽和花序的起始和发育过程中起重要作用.     

施氮对水稻植株和颖果发育及稻米品质的影响

以'扬稻6号'和'粳稻941'为材料,在施氮总量相同条件下分别设置低分蘖肥高孕穗肥和高分蘖肥低孕穗肥2个施氮处理,通过盆栽试验研究施氮量和施氮时期对水稻植株生长、颖果发育和稻米品质的影响.结果表明:水稻植株鲜重、干重、分蘖数和株高随分蘖期氮肥用量增加而增加;增加孕穗期氮肥用量比例能显著提高抽穗期水稻剑叶和颖果光合速率、颖壳叶绿素含量、呼吸速率、颖果CAT及SOD活性;增加孕穗期氮肥用量还能提高水稻籽粒出糙率、精米率、整精米率,降低稻米垩白率,改善稻米的碾米品质和营养品质.因此,增加分蘖期施氮比例能促进水稻植株生长,而提高孕穗期施氮量则有利于水稻颖果发育和稻米品质改善.     

DMT1编码一个丝氨酸/半胱氨酸蛋白酶调控水稻分蘖并参与干旱胁迫响应

水稻分蘖的形成是一个复杂的过程,受到环境及遗传因素的影响,合适的分蘖可以显著提高水稻产量.本研究利用甲基磺酸乙酯(ethyl methanesulfonate, EMS)诱变粳稻秀水11得到一份矮化、多分蘖突变体,将其命名为dwarf and multiple tillers 1(dmt1),并对其进行表型观察,生理生化分析,遗传分析,基因定位和激素处理.结果发现,在dmt1在分蘖期出现株高变矮,叶片面积变小,分蘖数增多等特征.遗传分析表明,该dmt1为单隐性核基因控制,图位克隆的结果显示, DMT1位于第4染色体上,编码一个丝氨酸/半胱氨酸蛋白酶,是NAL1的等位基因.亚细胞定位的结果表明, DMT1蛋白在细胞核、细胞质和叶绿体上均有表达.为探究该基因突变是否会影响水稻对激素的敏感程度,本研究通过施加外源激素发现dmt1地上部分对NAA敏感程度降低,而地下部分对于GA3敏感程度升高.并且在dmt1中生长素合成相关基因表达量降低.通过干旱处理发现dmt1的耐旱能力下降,在干旱胁迫下dmt1的发芽率降低.由实验可得, DMT1突变会导致植株产生株高变矮,分蘖增多的表型,通过qRT-PCR...     

虫压胁迫对抗虫转基因水稻生长发育及产量性状的影响

在大田条件下,以转基因抗虫水稻Bt63、R1和R2及非转基因水稻汕优63(对照)为材料,设置高、低两种虫压环境条件,研究虫压胁迫对转Bt抗虫基因水稻生长发育及产量相关性状的影响.结果表明： 抗虫水稻在虫压胁迫条件下可充分体现出外源基因的抗性特点.在高虫压条件下,3种转Bt基因水稻受螟虫危害程度远低于对照植株,株高、分蘖数、地上部鲜质量、穗长、穗质量、单株穗数、单株实粒数、实粒质量、结实率、千粒重等生长发育和产量指标均高于对照,但仅株高、分蘖数和穗长3个指标与对照有显著差异.因此,抗虫外源Bt基因的引入对水稻结实性不会产生负面效应,高虫压胁迫条件对抗虫转基因水稻产量的影响较小.     

水稻主茎和分蘖的一些生理生化特性的研究

前言水稻主茎和分蘖的生理生化特性,在水稻营养和水稻生产上都有重大意义。有关主茎与分蘖间营养物质转移方面,目前国内外有许多研究成果。但目前为止,有关分蘖的增产效果,人们还没有得到一致的结论,在探讨主     

The Plant Architecture of Rice (<Emphasis Type="Italic">Oryza sativa</Emphasis>)

Plant architecture, a collection of the important agronomic traits that determine grain production in rice, is mainly affected by factors including tillering, plant height and panicle morphology. Recently, significant progress has been made in isolating and collecting of mutants that are defective in rice plant architecture. Although our understanding of the molecular mechanisms that control rice tillering, panicle development and plant height are still limited, new findings have begun to emerge. This review, therefore, summarizes the recent progress in exploring the mechanisms that control rice plant architecture.     

Tillering and panicle branching genes in rice

Rice (Oryza sativa L.) is one of the most important staple food crops in the world, and rice tillering and panicle branching are important traits determining grain yield. Since the gene MONOCULM 1 (MOC 1) was first characterized as a key regulator in controlling rice tillering and branching, great progress has been achieved in identifying important genes associated with grain yield, elucidating the genetic basis of yield-related traits. Some of these important genes were shown to be applicable for molecular breeding of high-yielding rice. This review focuses on recent advances, with emphasis on rice tillering and panicle branching genes, and their regulatory networks.     

水稻耐盐碱性生理和遗传研究进展

水稻是对盐碱中度敏感的作物,其耐盐碱性因品种、生育阶段、器官、土壤盐碱类型等而存在差异。盐碱胁迫对水稻的伤害主要表现为延迟种子发芽时间、降低发芽率、抑制生育进程、阻碍幼穗分化、推迟分蘖时间、减少分蘖数、降低产量和品质。本文论述了近年来在水稻耐盐碱生理机理、转运蛋白、遗传和数量性状位点的分子检测、分子信号传导以及基因克隆转化方面的研究进展,并对今后的研究工作提出了建议。     

Identification and functional analysis of the MOC1 interacting protein 1

Rice tillering is one of the most important agronomic traits that determine grain yields.Our previous study has demonstrated that the MONOCULM1(MOC1)gene is a key component that controls the formation of rice tiller buds.To further elucidate the molecular mechanism of MOC1 involved in the regulation of rice tillering.we performed a yeast-two-hybrid screening to identify MOC1 interacting proteins(MIPs).Here we reported that MIP1 interacted with MOC1 both in vitro and in vivo.The overexpression of MIP1 resulted in enhanced tillering and reduced plant height.In-depth characterization of the context of MIP1 and MOC1 would further our understanding of molecular regulatory mechanisms of rice tillering.     

Branching in rice

Rice branching, including the formation of tillers and panicle branches, has been well investigated over the past several years because of its agronomic importance. A major breakthrough in elucidating rice tillering in the recent years was the discovery of strigolactones, a specific group of terpenoid lactones that can inhibit axillary bud outgrowth. Since that discovery, new tillering mutants, that is, dwarf 27 (d27) or dwarf14 (d14, also reported as d88 or htd2), have been identified with reduced strigolactone levels or strigolactone response. DWARF27 (D27) and DWARF14 (D14) probably act on strigolactone biosynthesis and signal transduction, respectively. Additionally, several genes controlling panicle branches have been identified recently. DEP1 and IPA1/WFP are essential dominant/semidominant regulators that determine rice panicle branches and thus affect the grain yields. More importantly, dep1 and ipa1 alleles have been shown to be applicable for the improvement of rice grain yields in molecular breeding.     

miRNA对水稻生长发育的调控

MicroRNA(miRNA)是一类小的非编码RNA,它们主要在转录后水平对靶mRNA进行切割或抑制mRNA的翻译来调控基因的表达. miRNA通过对靶基因的调控参与植物的生长发育、胁迫应答和代谢过程.在水稻中,已经发现并初步验证了许多与生长发育相关的miRNA,它们对水稻不同器官和形态发育发挥着重要作用.本文综述了水稻miRNA的发生和调控机制、靶基因的预测,重点介绍了miRNA对水稻生长发育和形态建成的研究进展,并对研究过程中存在的问题进行了讨论.为更好地了解miRNA及其靶基因在提高水稻产量和品质方面的作用,进一步解析miRNA在水稻中的调控机制提供参考.     

Genetic modification of plant architecture and variety improvement in rice

The structure of the aerial part of a plant, referred to as plant architecture, is subject to strict genetic control, and grain production in cereal crops is governed by an array of agronomic traits. Rice is one of the most important cereal crops and is also a model plant for molecular biological research. Recently, significant progress has been made in isolating and collecting rice mutants that exhibit altered plant architecture. In this article we summarize the recent progress in understanding the basic patterning mechanisms involved in the regulation of tillering (branching) pattern, stem structure and leaf arrangement in rice plants. We discuss the relationship between the genetic modification of plant architecture and the improvement of pivotal agronomic traits in rice.     

Inhibition of tillering in cereals by substituted 2-phenoxypropionic acids

The properties of various mono- and di-substituted analogues of 2-phenoxypropionic acid as inhibitors of tillering were investigated on wheat, barley and rice. Highest levels of activity were shown by (R)2-Cl,5-Cl, (R)2-Cl,5-F, and (R)2-Cl,5-methyl analogues. Few or no signs of phytotoxic effects (leaf chlorosis or necrosis) were evident on wheat or barley following spray application of these compounds. Rice was both more susceptible to inhibition of tillering and phytotoxic effects. However, almost complete inhibition of tillering was achieved by application of some compounds to rice with little or no phytotoxicity. Comparisons were made between the properties of these compounds and commercially used phenoxyacetic and phenoxypropionic herbicides and plant growth regulators. Dichlorprop inhibited tillering in rice, fenoprop in wheat and rice, and fluroxypyr in wheat, all without phytotoxic effects.     

独脚金内酯调控水稻分蘖的研究进展

水稻(Oryza sativa)作为世界上最主要的粮食作物之一, 对其主要农艺性状调控机理的研究具有重要意义。分蘖是水稻生长发育过程中一种特殊的分枝, 它不仅是与水稻产量密切相关的重要农艺性状, 也是揭示高等植物侧枝生长发育机制的理想模型。独脚金内酯(strigolactone, SL)是一类新型植物激素, 能够抑制植物分枝的生长发育。近年来, 关于SL合成与信号在调控水稻分蘖方面的研究取得了重要进展, 但对其信号转导的下游组分的研究还相对匮乏。该文综述了SL合成途径、信号途径及下游靶基因调控水稻分蘖的研究进展, 并与在拟南芥(Arabidopsis thaliana)、豌豆(Pisum sativum)和矮牵牛(Petunia hybrida)中的研究进行了比较, 同时还对如何挖掘SL途径的新组分进行了讨论。     

水稻不同生育期对荧光物——铕吸收运行的研究初报

本文为探索稻田生态系统营养关系定量分析研究方法的环节之一。作者首次采用标记示踪法测定了水稻在秧苗期,分蘖期,壮苞期,抽穗期,乳熟期等5个生育期吸收铕的情况为：同一处理浓度下,水稻根、茎、叶的铕含量在分蘖期最高,抽穗期最低,水稻中铕含量随生育期呈低-高-低-高的变化规律,秧苗期根、茎、叶的铕含量相近且低;分蘖期叶中铕含量比根和茎明显高;其它3个生育期茎与叶中铕含量相近并且比根部含量高。