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叶片的形态是理想株型的重要性状,叶片适度卷曲能提高水稻(Oryza sativa)群体的光能利用率,研究控制水稻叶片形态的相关基因能够进一步丰富株型理论。该研究在粳稻品系C275的群体中发现了1株自然变异的窄卷叶突变体nrl7(narrow rolled leaf 7)。与野生型相比,突变体的叶片变窄且向内卷曲;该突变体叶片连接中脉的泡状细胞严重变形,中脉与小叶脉之间的维管束数量均减少至1个。此外,突变体nrl7的株高、实粒数和实粒重均降低或减少,分别为野生型的88.46%、69.77%和68.98%,差异达极显著水平。叶片卷曲导致单叶光合速率减弱,与野生型相比,突变体的光合速率降低了17%,达极显著水平。突变体nr I7叶片的气孔导度、胞间CO2浓度和蒸腾速率则与野生型相比无明显变化。利用图位克隆的方法将目的基因定位于水稻第3染色体短臂上的分子标记RM5444和MM1300之间,物理距离约为185.14 kb。研究结果为该基因的克隆和进一步的功能分析奠定了基础。
Leaf morphology was an important trait of ideal plant type. Appropriate curling of leaves could improve the light energy utilization efficiency of Oryza sativa population. Studying the related genes controlling the leaf morphology of rice could further enrich plant type theory. In this study, a narrow-variant mutant nrl7 (narrow-rolled leaf 7) was found in a population of japonica rice lines C275. Compared with the wild type, the mutants’ leaves became narrower and curled inwardly. The bubble-shaped cells connected to the midrib of the mutant were severely deformed, and the number of vascular bundles between the middle and small veins was reduced to one. In addition, the mutant nrl7 plant height, grain number and grain weight were reduced or decreased, respectively, 88.46%, 69.77% and 68.98% of wild-type, the difference was extremely significant level. Leaf curl led to reduced single leaf photosynthetic rate, compared with the wild-type, the mutant photosynthetic rate decreased by 17%, reached a very significant level. Stomatal conductance, intercellular CO2 concentration and transpiration rate of mutant nr I7 leaves were not significantly different from those of wild type. Using the map-based cloning method, the target gene was located between the molecular marker RM5444 and MM1300 on the short arm of chromosome 3 of rice with a physical distance of 185.14 kb. The results laid the foundation for the cloning and further functional analysis of this gene.