| A total of 10 rice homozygous stem type mutants were obtained through MNU mutagenesis in the laboratory,including seven dwarf stem mutants and three multi tillering stem mutants.A total of 9 rice homozygous leaf type mutants were obtained,including five homozygous thin rolled leaf mutants and four homozygous wide leaf mutants.Through a series of characterization and identification of these 19 mutants,including the determination of changes in agronomic traits during their growth and development,the production and identification of paraffin sections,the determination of photosynthetic pigment content,the analysis of endogenous hormone content,and the analysis of genetic patterns by crossbreeding with Liaoyan 6 and breeding it to F2generation,the final comparison was made with the reported rice plant trait mutants,Furthermore,mutants with novel plant traits were screened out,as follows:1.The agronomic traits during the growth and development process of OSPM1-OSPM19were characterized,and the biological characteristics of the mutant plants were obtained.2.About the production and identification of OSPM1-OSPM19 paraffin sections,it is concluded that the main reason for the dwarf mutant OSPM1 plant to become shorter in the dwarf stem character of OSPM1-OSPM7 is that the length and width of parenchyma cells in the longitudinal section of the stem are significantly shortened,the main reason for OSPM2 plant to become shorter is that the length of parenchyma cells in the longitudinal section of the stem is significantly shortened,and the main reason for OSPM3 plant to become shorter is that the number of parenchyma cells in the longitudinal section of the stem is reduced,The shortening of OSPM4plants is due to the extremely significant shortening of the width of longitudinal parenchyma cells and the significant shortening of cell length.The reason for the shortening of OSPM5 plants is due to the shortening of the length and width of longitudinal parenchyma cells.The reason for the shortening of OSPM6 plants is that the length and width of longitudinal parenchyma cells are reduced by nearly the same proportion at the same time.The reason for the shortening of OSPM7 plants is due to the shortening of longitudinal parenchyma cells.The dwarfing of OSPM8-OSPM10 is also related to the changes of longitudinal parenchyma cells.The narrowing of OSPM11-OSPM15 leaves is associated with a decrease in the size and number of vascular bundles,while leaf curling is associated with changes in the volume and number of vesicular cells.Except for OSPM17,the leaf width of the OSPM16-OSPM19 mutant is related to an increase in the volume of the midrib and the number of vascular bundles of different sizes.3.The chlorophyll content of flag leaves during the heading stage of four homozygous wide leaf mutants was measured,and it was found that the reason for the deepening of leaf color in OSPM16-OSPM19was due to an increase in both chlorophyll a and chlorophyll b content.However,the chlorophyll a and chlorophyll b content of these four mutants were inconsistent.4.The determination of endogenous hormone content of OSPM1-OSPM15 showed that only OSPM5 had less auxin content in OSPM1-OSPM7,and the dwarfing of other plants had nothing to do with less endogenous auxin content,and the dwarfing of these seven dwarfing mutants was not caused by less endogenous gibberellin content in plants;The increase of tiller number of OSPM8-OSPM10 was not related to the deficiency of plant endogenous auxin content;With regard to OSPM11-OSPM15,only OSPM14 contains less auxin,gibberellin and cytokinin,which is an important reason for OSPM14’s short plant size and flag leaf curl.The flag leaf curl of the other four thin leaf mutants has nothing to do with endogenous hormone defects.By comparing with the reported endogenous auxin related mutants,onlyγ-rl,the concentration of endogenous auxin in the mutant is significantly lower than that in the wild type.The reason for the leaf curl of the mutant is that the volume of vesicular cells decreases and the number increases,while the leaf curl of OSPM14 is caused by the volume increase and number increase of vesicular cells,which is inconsistent with the reported mutation traits.Therefore,OSPM14 is a new mutant formed by the gene mutation involved in the synthesis of endogenous auxin.5.Genetic pattern analysis revealed that all 7 dwarf mutants were regulated by one pair of single cryptic nuclear genes.The three multi tillering mutants are all controlled by a pair of single cryptic nuclear genes.Except for OSPM14,which is a pair of single dominant single cell nuclear genes,the remaining OSPM11,OSPM12,OSPM13,and OSPM15 are all regulated by a pair of single dominant single cell nuclear genes.Except for OSPM17,which is regulated by a pair of single recessive nuclear genes,the other broad leaf mutants are regulated by a pair of single recessive nuclear genes.Compared with the reported wide leaf mutants and leaf color mutants through literature review,there is no wide leaf mutant with increased midvein volume due to the increase in the number of midvein air chambers,and this series of mutants also have dark green leaves,so OSPM16,OSPM18,and OSPM19 are all new mutants.Ultimately,it is clear that OSPM14,OSPM16,OSPM18,and OSPM19 are all novel mutants. |
