【作者】 杨扬；

【导师】 孙越；

【作者基本信息】 华东师范大学 ， 植物学， 2010， 硕士

【摘要】 uro(upright rosette)突变体是从T-DNA插入突变体库中筛选得到的一个叶发育异常的半显性突变体。这个突变体在幼苗生长时期,其莲座叶表现为竖直向上(偏下性)生长的方式,成熟植株表现出明显的顶端优势丧失、束间纤维发育异常、侧枝较野生型多、茎杆软等特征。前期研究成果表明了URO基因能够调节自由态生长素和结合态生长素之间的比例来调控生长素的动态平衡,uro突变体这些生长素相关的表型是由URO基因过量表达造成的。在培养过程中发现uro突变体对水分的需求量少于野生型,为了研究了uro突变体是否比野生型耐旱性提高以及如何提高,观察了突变体在干旱胁迫条件下的生长状态,测定了离体地上部分的含水量及失水率变化情况,并且施加了外源ABA考察突变体对ABA的敏感性变化,也考察了突变体根系发育情况及表皮毛分布,测定了突变体中丙二醛的含量,初步分析证明了突变体中植株衰老延缓,导致了耐旱能力的增强。为了更进一步研究URO基因的功能,通过将URO基因启动子连接GUS报道基因转化野生型拟南芥后,发现URO基因主要在营养生长期表达。URO基因主要作用与植株营养生长有关。本研究证明了uro突变体耐旱能力的确较野生型增强,初步探究了其耐旱机理,并且对URO基因的表达模式进行了分析,发现了URO基因的功能与营养生长有关,uro突变体中,由于URO基因过量表达,导致自由态生长素含量增加,可以增强植物的营养生长,延缓衰老从而达到抗旱效果。更多还原

【Abstract】 The Arabidopsis semi-dominant leaf mutant, upright rosette (uro), was obtained from a T-DNA insertion-population. The seedling of uro have a phenotype of upright-growing rosette leaves, when grown up, it displays pleiotropic phenotypes including loss of apical dominance, interfascicular fiber development anomaly, the number of lateral branch increased, softening and thicking of shoot stem.Our previously results show that the overexpression of URO gene in mutant caused these auxin-related phenotypes, because the gene alter IAA homeostasis throught control the proportion of free and conjugated IAA. It was found that the uro mutant needed less water than wild type. In order to study whether the uro mutant increased drought tolerance than wild-type and how to improve, mutant was observed under drought stress. At the same time, other studies were carried on. The water content of detached shoots and water loss rate was measured. The sensitivity of mutant to exogenous ABA, the development of root and trichome distribution was investigated, and the content of MDA was determination. The preliminary analysis shows that the senescence of uro mutant delayed that was caused enhancing drought tolerance.To further study the functions of URO genes, the analysis of gene expression patterns of URO, we connect gene promoter with GUS reporter, then transgenic wild type Arabidopsis thaliana.It was obtained that the URO gene major expressed in vegetative growth stage. The main function of URO has some connection with the vegetative growth.This study proved that the uro mutant has enhanced drought tolerance than wild type. We have studied the possible drought tolerance mechanism of uro mutant and analysis the URO gene expression pattern. The results indicate that the URO gene may involved in Arabidopsis vegetative development process through free IAA concentration regulation. The overexpression of URO gene in mutant caused an increase in the free IAA concentration. This change can enhance drought tolerance because the enhancement of vegetative growth can delay the senescence of uro mutant.更多还原