一份水稻叶片反卷突变体的遗传分析及电镜显微观察

叶片是植物进行光合作用的重要器官。叶片适度卷曲能够提高水稻(Oryza sativa)生长中后期群体基部的光能利用率, 因而有利于水稻产量的提高。该研究首先在水稻T-DNA插入突变体库中发现一份叶片反卷的突变体。遗传分析表明, 该性状受到1对隐性核基因控制。扫描电镜观察结果显示, 突变体成熟叶片上下表皮的气孔发生了畸变; 且叶片上表皮气孔数目增多, 而下表皮气孔数目与野生型基本相同。叶片横切面电镜观察结果表明, 与野生型相比, 突变体叶片的泡状细胞数目和面积在早期(二叶期)就开始增加, 在成熟期更加明显, 这可能是导致叶片反卷的主要原因。

Genetic Analysis and Scanning Electron Microscopy of an Abaxial Rolled-leaf Mutant in Rice

The leafs has long been considered an important organ for photosynthesis. Moderate leaf rolling in rice leads to erect leaf canopies and increased photosynthetic efficiency, improving stress response by reducing transpirational water loss and radiant heat absorption, thereby increasing grain yield. Therefore, moderate leaf rolling is an ideal trait for rice breeding. During screening of rice T-DNA insertion lines, a stable mutant showing abaxial rolled-leaf phenotype was obtained. Genetic analyses of heterozygous F₁ progeny showed that the mutant phenotype segregated in a 3:1 ratio of wild-type and mutant-like plants, so the leaf-rolling phenotype was caused by a single recessive mutation. Scanning electron microscopy revealed that stomatal phenotypes of mature leaves were changed and stoma number was increased in the mutant compared with wild type. In cross sectons taken from similar positions, the bulliform cell number and area were larger in the mutant than the wild type, which suggests that the outcurved leaf phenotype may be caused by the increase in bulliform cell number and size.