玉米碳水化合物分配缺陷突变体ygl3的光合特性及遗传分析

Photosynthetic Characteristics and Genetic Analysis of the Maize Carbohydrate Distribution Deficient Mutant ygl3

以快中子辐射诱变玉米自交系PH6WC筛选得到的碳水化合物分配缺陷突变体ygl3为材料,通过叶片内叶绿素含量和碳水化合物含量的测定、叶绿体结构显微观察、光合特性和遗传特性等进行分析。结果表明,与野生型相比,突变体叶绿体数目变少,形态松散,维管束鞘叶绿体积累了大量的淀粉,淀粉颗粒排列不规则且体积增大,导致了叶绿体的膨胀和膜结构的破坏;叶片中淀粉、葡萄糖、果糖的含量都显著高于野生型,表现出玉米碳水化合物分配缺陷的典型表型特征;突变体的叶绿素a、叶绿素b及总叶绿素含量都显著低于野生型;净光合速率(Photo)、气孔导度(Cond)、蒸腾速率(Trmmol)均极显著低于野生型,胞间二氧化碳浓度(Ci)高于野生型。遗传分析表明,(ygl3×Mo17)F_(2)分离群体突变型(黄化)与野生型(绿色)植株性状分离符合1∶3分离比例,表明该突变体受单个核隐性基因控制。

A carbohydrate distribution deficient mutant ygl3 derived from fast neutron radiation with an elite maize line PH6WC was used to determine leaf chlorophyll and carbohydrate content,microscopic observation of chloroplast structure,photosynthetic and genetic characteristics.The results showed that the ygl3 mutant chloroplast had fewer number and looser morphology,a large amount of starch accumulated in the chloroplasts of vascular bundle sheath,and the irregular arrangement and increased volume of starch particles lead to the expansion of chloroplasts and the destruction of membrane structure in comparison with the wild type.The contents of starch,glucose and fructose in the leaves were significantly higher,while the contents of chlorophyll a,chlorophyll b and total chlorophyll,and photosynthetic parameters,net photosynthetic rate(Photo),stomatal conductance(Cond)and transpiration rate(Trmmol),were significantly lower than those of the wild type,exhibiting typical phenotypic characteristics of carbohydrate allocation defects in maize.Genetic analysis showed that the separation ratio of mutant type(yellow)and wild type(green)in F_(2) population of ygl3×Mo17 was 1:3,explaining that the yellow mutant was controlled by a single nuclear recessive gene.