水培拟南芥中芥子油苷组成与含量的初步分析

利用HPLC-MS联用分析方法测定了水培拟南芥莲座叶和根中芥子油苷的组成和含量。水培拟南芥莲座叶和根中检测到的主要芥子油苷分别为10种和12种,其中8种为两者共有。脂肪族芥子油苷和吲哚族芥子油苷在莲座叶和根中的含量相差很大,莲座叶中脂肪族芥子油苷含量是根的3.65倍,而根中吲哚族芥子油苷的含量是莲座叶的1.51倍。莲座叶中含量最高的是脂肪族的4-甲基亚磺酰丁基芥子油苷,占芥子油苷总量的42.62%,而根中则是吲哚族的1-甲氧吲哚基-3-甲基芥子油苷的含量最高,占芥子油苷总量的29.37%。     

Light perception in higher plants

Photosynthetic plants depend on sunlight as their energy source. Thus, they need to detect the intensity, quality and direction of this critical environmental factor and to respond properly by optimizing their growth and development. Perception of light is accomplished by several photoreceptors including phytochromes, blue/ultraviolet (UV)-A and UV-B light photoreceptors. In recent years, genetic, molecular genetic and cell biological approaches have significantly increased our knowledge about the structure and function of the photoreceptors, and allowed the identification of several light signal transduction components. Furthermore, this research led to fruitful interaction between different disciplines, such as molecular biology and ecology. It is safe to assume that we can expect more milestones in this research field in the upcoming years.     

两种拟南芥coi1突变体的鉴定与初步分析

COI1(coronatine-insensitive 1)蛋白是茉莉酸信号途径的信号开关,coi1突变体是茉莉酸信号调控机制研究中的重要实验材料。对从拟南芥生物资源中心购买的两种COI1(At2g39940)的T-DNA插入突变体SALK-095916和SALK-045434,通过基因型分析筛选获得了纯合突变体。进一步的基因表达检测和茉莉酸敏感性试验表明,两种纯合突变体中COI1基因的表达量分别约为野生型植株的40%和50%,突变体幼苗对茉莉酸的敏感性显著降低。获得的SALK-095916(命名为coi1-22)和SALK-045434(命名为coi1-23)纯合突变体可以作为实验材料在进一步的茉莉酸信号途径机制研究中使用。     

Ethylene-induced nitric oxide production and stomatal closure in <Emphasis Type="Italic">Arabidopsis thaliana</Emphasis> depending on changes in cytosolic pH

We investigated changes in cytosolic pH and nitric oxide (NO) during ethylene-induced stomatal closure in Arabidopsis thaliana using pharmacological, laser scanning confocal microscopy (LSCM), and spectrophotography techniques. Treatment with ethephon (a direct source of ethylene when applied to plants) and 1-aminocycloaminopropane-1-carboxylic acid (ACC, an ethylene precursor) resulted in a rapid accumulation of NO and cytosolic alkalinization in guard cells. Acetic acid (a weak acid) and sodium orthovanadate (NaVO3; a plasmalemma H+-ATPase inhibitor) reduced stomatal closure induced by ethylene and blocked ethylene-induced activity of nitrate reductase. However, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO), a NO scavenger, had no effect. These results suggest that NO production is downstream of the rise in cytosolic pH in A. thaliana.     

拟南芥温敏雄性不育突变体atms1的获得及表型分析

从甲基磺酸乙酯（ethylmethane sulfonate,EMS）化学诱变建立的野生型拟南芥（Col-0）突变体文库中筛选到1株突变体.在低温16 ℃时,该突变体的雄性育性与野生型没有显著差异,花粉染色呈现100%可育.随着培养环境温度的升高,突变体花粉育性逐渐下降,因此,该突变体为一温敏雄性不育突变体,并被命名为atms1（ambient temperature-sensory male sterility 1,即环境温度敏感雄性不育1）.花药切片结果显示,在23 ℃以下,该突变体花药各个发育时期的形态与野生型花药没有显著的差异;而27 ℃处理1周后的突变体花药呈现多种表型：同一朵花中各个花药的发育时期出现显著分化,花粉母细胞胼胝体单薄,绒毡层发育滞后于同时期的野生型花药.遗传分析确定,atms1的不育表型是由单个隐性核基因控制的.     

新疆塔尔巴哈台山南麓拟南芥生存群落的种间联结特征

为揭示影响拟南芥分布的主要生物因素,本研究对塔尔巴哈台山南麓拟南芥(Arabidopsis thaliana)生存群落内16个主要物种做种间联结性分析,结果表明:物种总体联结方差比率为1.474,表现为显著正联结。其中有65.83%的种对表现出正关联,余下表现为负关联;χ2检验为显著或极显著关联的种对有35对,其中正关联26对,负关联9对;有77.5%的种对关联强度指数(OI)0.6,χ2检验联结性多不显著;优势种对间的OI值基本都0.6,多为显著或极显著正联结。去势对应分析表明,主要优势种都聚集在排序图中央,种间联结紧密,而次要种则零散于其周缘,连接性较弱。16个物种分成2个生态种组,但组间界限不明显。拟南芥与群落主要优势种关系密切,对其依赖性较强,表明群落优势种是影响拟南芥生存分布的主要生物因素。     

拟南芥（Arabidopsis thaliana）种群间及近远缘种表型整合的分化研究

表型整合是生物形态、生理和功能之间以及三者之内特征的相关性。表型整合的进化是生物进化研究的重要内容。拟南芥（Arabidopsis thaliana）是植物遗传、生理和进化生物学研究的模式植物,但目前采用现代比较方法,将拟南芥形态与生理功能特征相结合研究表型整合较少。本研究选取了石河子（新疆）、青河（新疆）、浙江、美国（哥伦比亚）等拟南芥四个种群,以及新疆境内小拟南芥（Arabidopsis pumila）、南芥（Arabis auriculata）和庭荠（Alyssum desertorum）等拟南芥近远缘种作为实验材料,在同一环境下,研究形态、光合生理、生活史等特征,以及表型整合特征在种内和种间的分化特点。结果表明：石河子种群与另外三种种群之间的单个特征差异明显,各种群在两两特征之间相关格局分化较大。共同主成分分析（CPCA—Common Principal Component Analysis）发现石河子、青河、浙江三种中国种群的整合格局相同,而美国种群与其它三个拟南芥种群间的共同主成分相对较少;物种整合格局的分化与系统关系的远近有较大的关系,同时也与自然选择压紧密相关。     

一个拟南芥C2H2锌指蛋白的结构域分析

At3g23140是拟南芥中仅含有一个C2H2锌指结构的转录因子,主要含有N端的C2H2锌指结构和C端的类似EAR两个结构域.将〖WTBX〗〖STBX〗At3g23140〖WTBZ〗〖STB3〗中仅含C2H2锌指结构区域不同长度的两个基因片段〖WTBX〗〖STBX〗A1〖WTBZ〗〖STB3〗(240 bp),〖WTBX〗〖STBX〗A2〖STB3〗〖WTBZ〗(410 bp)克隆到植物表达载体pMON530 35S启动子的下游,并转化野生型拟南芥.经过筛选得到稳定遗传的T3代纯合转化子.对转基因植株研究表明, 35S::〖WTBX〗〖STBX〗A2〖STB3〗〖WTBZ〗转基因植株的内源乙烯释放量明显低于野生型,这与〖WTBX〗〖STBX〗At3g23140〖STB3〗〖WTBZ〗插入失活突变体〖WTBX〗〖STBX〗cs16966〖STB3〗〖WTBZ〗的表型是一致的,而35S::〖WTBX〗〖STBX〗A1〖WTBZ〗〖STB3〗转基因植株的内源乙烯释放量与野生型没有明显区别.表明A2片段的过量表达产生了显性抑制的作用,这种显性抑制效应很可能是由于 A2蛋白片段与〖WTBX〗〖STBX〗At3g23140〖STB3〗〖WTBZ〗表达产物所调控的核酸序列竞争结合所导致.而A2片段C端所含有的非锌指结构域是At3g23140蛋白与靶基因序列结合所必需的.     

Cellulose synthesis: mutational analysis and genomic perspectives using Arabidopsis thaliana

Cellulose microfibrils containing crystalline β-1,4-glucan provide the major structural framework in higher-plant cell walls. Genetic analyses of Arabidopsis thaliana now link specific genes to plant cellulose production just as was achieved some years earlier with bacteria. Cellulose-deficient mutants have defects in several members of one family within a complex glycosyltransferase superfamily and in one member of a small family of membrane-bound endo-1,4-β-glucanases. The mutants also accumulate a readily extractable β-1,4-glucan that has short chains which, in at least one case, are lipid linked. Cellulose could be made by direct extension of the glucan chain by the glycosyltransferase or, as the mutant suggests, by an indirect route which makes lipid-linked oligosaccharides. Models discussed incorporate the known enzymes and lipo-glucan and raise the possibility that different CesA glycosyltransferases may catalyse different steps. Received 5 January 2001; received after revision 25 April 2001; accepted 25 April 2001