| Morphological Observation, Genetic Analysis And Gene Mapping of Three Mntants Involved InReproductive Development In Rice(O. Sativa L)The acquisition and research on the mutants related to reproductive development played an important role in uncovering the function and interaction of genes in reproductive process, especially in floral development. Research on rice reproductive mechanism is significant both in theory and in human agriculture. The mutant strains called in this paper leafy head(lhd), fizzle panicle(fzp) and degenerated reproductive organs (dro) were found by our research group, and the genes involved were named as lhd(t), frp(t) and dro respectively. lhd and dro were found in a double haploid(DH) population from the cross between Taiwanjing and Gui630 derived by anther culture. fzp was obtained from the progeny of the cross between V2OB and HualB. We have conducted researches on lhd, fzp and dro in three aspects: morphological and anatomical observation, genetic analysis and gene mapping, setting strong foundation for further research, for example, gene expressing and gene cloning, in the near future.The lhd mutant plants were shorter in height, had much more small leaves which appeared to be clump, and produced many leafy braches with small leaves at the top of the stems simultaneously with the heading of normal plants. Thus, i/id mutant plants did not enter the stage of reproductive development. Based on anatomical observations of the growing point, shoot apex of lhd was smaller than the normal plants at the vegetable stage. During the panicle primordial differentiation of normal plants, lhd plants tended to generate many branches and leaves. Corresponding to the four stages of development: bract primordial differentiation, the first rachis primordial differentiation, the second rachisprimordial differentiation and flower primordial differentiation, the course of development branches and leaves in lhd plants was divided into four stages: the preliminary stage of the growing point changing to a shoot apex, the first braches development, the second braches development, and the leaf buds development from the braches. It is obvious that lhd(t) was the key gene controlling inforescence primordial differentiation in rice, however, it probably took its effects on the preliminary stage of vegetable growth.The fzp mutant plants looked like normal plants, but had less tillers than the normal ones. Instead of spikelet differentiation and development, fzp mutant plants developed a block of rachis braches. Based on anatomical microscope observations, the development stage of the first and the second rachis braches appeared to be normal, but small braches, instead of spikelets, continued to be produced. It seemed that these branches appeared to produce multiple rachillas. Thus, fzp(t) was the key gene controlling spikelet primordial differentiation and development, and probably took its effects on the stage of tillering.The phenotype of dro mutant plants seemed to be normal. However, the spikelets of dro were larger than the normal ones, and it s stamens and pistils were totally degenerated, with many lays of glumes instead. Based on anatomical observations, flower primordial differentiation in dro plants tended to be normal at the preliminary stage. After that, the traits of flower primordial became different between dro plants and normal ones. Pistils and stamens were developed in normal plants, instead of many lays of glumes in dro plants. It is obvious that dro was the key gene controlling floral organ primordial differentiation and development in rice, and probably took its effects in the preliminary stage of the floral organ primordial differentiation.Progeny derived from lhd, fzp and dro heterozygotes, showed a good fit to 3:1 ratio of the normal plants to the mutant plants. These three mutants were controlled by a single recessive gene. However, when lhd(t), fzp(t) and dro genes are put into genetic backgrounds largely different from the original mutant plants,...
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