| Through physical and chemical mutagenesis generated loss-of-function mutant and obtained function mutant gene illustrated the functions of genes. It was one important way to study functional genomics.We obtained a rice mutant hk759obtained from wuyunjing7by heavy ion irradiation.On the study, we mainly researched the agronomic characters, physiological and biochemical, the environment factors and regulation mechanism of helical formed and genetic analysis. The experiment conclusions as follows:1Study on characteristics of mutant hk7591.1The helical growth characteristics of mutant expressed during the whole plant growth and the whole plant organs. The mutant showed helical growth at seeding stage. The mutant showed anticlockwise helical growth in the root, leaves, stem and grains at mature stage. At mature stage, the mutant also showed tiller angle increased, plant type loosed, dwarf, leaf half rolled and part helical. The root length and number of mutant also significantly increased. The helical degree was significantly enhanced. The hull dehiscence rate was high.1.2The helical form was conducted by uneven growth of cells. We observed it from the longitudinal section of helical stems by paraffin section. In the normal part of mutant, the number and length and width ratio between left and right epidermal cells were the same. But in the helical part of mutant, the inner epidermal cells length of the helical part were smaller than the outside epidermal cells length of the helical part. Only were88%of the outside epidermal cells of the helical part. The inner epidermal cells width of the helical part was1.08times wider than the outside.1.3Genetic analysis showed that the mutant was controlled by a single recessive gene and its genetic stability. The mutant gene was mapped on2suspected sites.2. Study on helical mechanism of mutant hk7592.1. The helical growth characteristic was relation to light. With the light intensity, increased, the helical degree and the helix number of mutant were reduced. The diameter of the helical coil was increased. Then move the plant from the dark to the normal light. The helical degree of mutant was increased with growth time increasing under dark condition in early days.2.2. The helical growth characteristic was relation to root exudates.hk759could induce the aboveground of wild type showed different helical growth. Separated the aboveground and the underground of hk759and wild type respectively, the former would show weak helical growth; the later would not show helical growth. As number of the mutant touched wild type underground increasing, the ratio of helical growth plant and helical degree were increased. The helix number of mutant was increased and the diameter of the helical coil was reduced. The helical degree was more tightly.2.3The helical growth characteristic was relation to endogenous hormone IAA of rice. We determined IAA, ABA and GA content of hk759and wild type rice seedlings at three leaves stage by HPLC. IAA content of mutant seedlings was6.15μg·g-1. It increased by 46.7%compared with the wild type. The content of ABA was0.355μg·g-1reduced by27.7%compared with the wild type. Content of GA was2.52μg·g-1. It had no significant changes compared with wild type.The exogenous hormone responsiveness experiment indicated, compared to wild type hk759was more sensitive to IAA. As the IAA content increasing, the helical degree of hk759was enhanced. The helix number of mutant was increased and the diameter of the helical coil was reduced. The helical degree was more tightly. When the IAA content reached8mg·L-1, the helix number was2.72, and the diameter of the helical coil was only3.42cm. There were2.06times and82.3%of blank control respectively. |
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