Studies On Morphological And Physiological Of Two Rice Leaf Mutants

Rice yield is closely related to the photosynthetic function and leaf cell senescence.To clarify its physiological mechanism and gene regulatory network can provide theoretical references for high-yield rice breeding.In this study,two mutants of leaf color and early leaf blight are obtained by radiation mutation of cobalt 60.The changes of main morphological and physiological indexes of the two mutants are studied.The main conclusions are as follows:?1?The plant height of the leaf color mutant F7-27 is significantly shorter than that of the wild-type plant,and its flag leaf angle is smaller,and the leaves are short and narrow.After the three-leaf stage,the green leaves become pale,and the color remains until the mature stage.There is no significant difference between the mutant and the wild type in panicle number per plant,grain number per panicle and panicle length,but the seed setting rate and 1000 grain weight decrease,and the grain length and grain thickness decrease.The amylose content of the mutant decreased significantly,but the protein content changed little.The peak viscosity,cool paste viscosity,final viscosity and setback value of RVA decrease significantly,while the breakdown value increase.The chlorophyll content of the mutant decrease,and the cell morphology and leaf surface structure of the mutant are almost the same as those of the wild type.The results show that the shape of chloroplast is irregular,and a large number of starch granules are accumulated in the chloroplast,osmiophilic granules were significantly reduced,and the lamellar structure of chloroplast matrix was loose and irregular.The chlorophyll fluorescence parameters of the mutant f7-27,such as Fo,Fm and Fv,decreased,but Fv/Fo and Fv/Fm are almost the same as those of the wild type,indicating that the mutant and the wild type have the same potential photochemical activity and the maximum photochemical efficiency of PS?original light energy,but the ability of light capture and absorption of mutant is lower than that of wild type.?2?The plant height,panicle number per plant,grain number per panicle,seed setting rate and 1000 grain weight of f5-155 are significantly decreased,and the leaves are longer and narrower,and the grain type is also longer and narrower.The amylose content and protein content of the mutant are decline,and the peak viscosity,final viscosity and cooling value of RVA increase,and the peak time decrease.The results of paraffin section show that there is no obvious change in the cell morphology of the mutant leaves.However,the bristles,tubercles and epidermal cells of the mutant are destroyed,the wax layer on the surface of the leaves become fuzzy,and the stomatal opening is smaller,and the leaves show signs of withering and senescence.The mutant show a significant decrease in chlorophyll content.The results of Evans blue staining show that a large amount of H₂O₂ is accumulated in the leaves of the mutant,and there are a lot of cell necrosis.The chlorophyll fluorescence parameters Fo,Fm,Fv,Fv/Fo,Fv/Fm of the early leaf withering mutants are all significantly reduced,indicating that the light energy absorption and transformation capabilities of the mutants have decreasedCompared with the wild type,the two mutants showed significant changes in plant morphology,and physiological functions showed that the content of chlorophyll was reduced,and the photosynthetic capacity of leaves was reduced,which led to the reduction of biological yield,seed setting rate and grain yield of the two mutants.At the same time,it also affected the accumulation of protein and starch in the mutant grain and the viscosity of starch.The chloroplast structure of the leaf color mutant is abnormal,and the cells of the early leaf withering mutant die prematurely.This study clarify the main characteristics of these two mutants,laying the foundation for further gene mining and functional analysis.