| In order to understand the dwarfing mechanism of dwarf mutants of common wheat variety Shaannong 33, agronomic traits, stem cell cytology, GA3 reaction of seedling, endogenous hormone, and dwarf gene were analysed. The reasons for dwarfing were analyzed from plant growth and development, stem anatomical characteristics, and the effects of hormones. The results showed that compared with the wild-type Shaannong 33, the plant height of dwarf mutants was significantly decreased. The decline in plant height was not related to the number of internodes, but mainly due to the shortening of the internode length, among which, the dwarfing effects of peduncle and the fourth internode were obvious. Microscopic observation of the cells showed that the reduction in plant height was caused by the shortening of the cell length and the decrease in the size of the cells, of which, the shortening of the cell is the main factor. GA3 reaction at the seedling stage showed that 13 dwarf mutants were GA-insensitive or weak-sensitive, indicating that there is a problem with the GA transduction pathway, the mutation site may be in the GA transduction pathway. From the results of endogenous hormone determination, the content of endogenous GA3 in 12 dwarfing materials was increased compared with that in Shaannong 33. Only one material was decreased slightly, while the content of endogenous CTK was decreased compared with that in Shaannong 33. It can be speculated that the accumulation of GA3 and the decrease of CTK affected the growth and development of the plants. By dwarf gene detection, 13 dwarf mutants and Shaannong 33 all contained Rht-D1b gene with a wide range of applications. It is inferred that dwarf mutants may also contain other dwarfing genes. |
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