Abstract:

Photosynthesis serves as the main way for crops to accumulate biomass in agricultural production， which primarily depends on a variety of photosynthetic pigments as well as complete chloroplast structure and function. Maize leaf color mutants are crucial to study the development of chloroplasts and improve photosynthesis capacity and maize yield. In this study， two maize inbred lines Z58 and B73 were used as control in order to compare the difference between morphological characteristics， photosynthetic pigment content and chlorophyll synthesis precursor content among three maize yellow leaf mutants yl?1 （yellow leaf?1， Z58 background）， yl?2 （yellow leaf?2， B73 background） mutated by ethyl methanesulphonate （EMS） and a natural yellow?leaf mutant yl?3 screened from Z58. The results showed that the three mutants exhibited different levels of yellowing phenotype throughout their growth cycle and no greening， dwarf plants， and delayed growth compared to the control. Total chlorophyll， chlorophyll a and chlorophyll b were significantly decreased （P<0.05）， while the ratio of chlorophyll a/chlorophyll b was significantly increased （P<0.05）. The content of various precursors for chlorophyll synthesis among the different mutants all decreased. The yellow leaf phenotypes of the three mutants may be caused by the abnormal synthesis of related tetrapyrrole compounds due to mutations in different genes. This study laid a theoretical foundation for locating the mutant genes that cause the yellow leaf phenotype of the three mutants and further exploring their utilization potential.

Key words: maize, leaf color mutant, photosynthesis, chlorophyll synthesis

摘要：

在农业生产中光合作用是作物积累生物量的主要方式，其主要依赖于多种光合色素和完整的叶绿体结构与功能。而玉米叶色突变体对于研究叶绿体发育、提高玉米光合作用能力和产量具有重要意义。以两个玉米自交系郑58（Z58）和B73为对照，对从甲基磺酸乙酯（ethyl methanesulphonate，EMS）处理后的不同玉米诱变群体中筛选到的2株黄叶突变体yl?1（yellow leaf?1，Z58背景）、yl?2（yellow leaf?2，B73背景）以及从玉米自交系Z58中发现的1株自然黄叶突变体yl?3（yellow leaf?3）等3个表型相似的玉米黄叶突变体的形态特征、光合色素含量、叶绿素合成前体物质含量进行了比较研究。结果表明，与对照相比，3个突变体在整个生长周期内均呈现不同程度的黄叶表型、不复绿、植株矮小、发育迟缓；叶片总叶绿素、叶绿素a和叶绿素b含量均显著降低（P<0.05），叶绿素a/叶绿素b比值显著升高（P<0.05）；不同突变体的各类叶绿素合成前体物质含量有不同程度的降低。3个突变体的黄叶表型可能是由不同基因的突变导致相关四吡咯化合物合成异常引起的。研究结果为定位引起3个突变体黄叶表型的突变基因和进一步探讨其利用潜力奠定了理论基础。

关键词: 玉米, 叶色突变体, 光合作用, 叶绿素合成