Characterization Of A Novel Yellow Leaf Color Mutant Ygm And A Low-temperature-sensitive Purple-stripe-leaf1 (PSL1) Mutant In Common Wheat

Wheat is one of the most important food crops in China,and its yield will directly affect the food security of our country.Under the current situation of reducing the area of arable land nationwide,the problem of increasing wheat yield is important.The key factors affecting wheat yield are the photosynthetic efficiency of wheat,and the photosynthetic efficiency is closely related to the development of wheat chloroplast.Therefore,it is of great significance to explore the genetic and physiological mechanisms of wheat chlorophyll synthesis and chloroplast formation and development.In this study,the following studies were carried out on the near-isogenic lines of yellow-green wheat and the newly discovered low-temperature sensitive wheat-stripe leaf stripe mutations: 1.The main physiological indexes and chloroplast ultra-structure of the near-isogenic lines of yellow-green wheat were measured and observed.2.The phenotypic changes,thermo-sensitive characteristics,main physiological indexes,chloroplast ultra-structure,photosynthetic pigment content,photosynthetic characteristics,agronomic traits,antioxidant enzyme activities and genetic characteristics of low-temperature sensitive wheat white-stripe mutants were measured,observed and analysis.The results show that:1.The results of yellow-green wheat: In order to study the main physiological characterization,morphology and ultra-structure of chloroplast on the yellow-green leaf color mutant,three near-isogenic lines(NILs)(xantha line 1-20 YY,yellow-green line 1-20 YG and green line 1-20GG)derived from this mutant were used by examination of the content of soluble substances,activity of a series of antioxidant enzymes,and morphology and ultra-structure of chloroplast.The results laid a foundation for further study of the biological mechanism of this wheat yellow-green leaf color mutant.2.The results of the study on low temperature sensitive wheat purple-stripe leaf color mutants PSL1: Through the study found that this leaf color mutant is a chlorophyll-less mutant whose genetic is controled by cytoplasm,and it affected by temperature?Its offspring will separate the three phenotypes,including P type,Ps type and G type,causing leaf color changes in temperature 5? or less,and leaf color will gradually returned to normal greenwhen temperature is 6? or higher.There were a significant difference in the main physiological indexes,photosynthesis indexes and chloroplast ultrastructure between mutant and wild type after the leaf color changed.The expression quantity of leaf soluble matter content and antioxidant enzyme activity reduced in the period of mutation,then back to normal level after the leaf color to normal.Distribution and ultrastructure of the chloroplast also have a series of changes when mutation occurs,such as distribution of chloroplast messy,shape without rules,stroma and grana thylakoid cracking and so on,these changes can be restored after the leaf color returned to normal.The above results will provide a basis for further study of the material and provide theoretical basis for the research of the wheat photosynthesis mechanism.