矮杆和半矮杆大豆突变体植株生长对外源GA3的响应

矮杆和半矮杆突变体是研究植物基因功能和培育高产作物新品种的重要材料。本研究以矮杆和半矮杆大豆突变体与各自野生型品种为材料, 利用外源赤霉素(GA₃)处理不同发育时期植株, 研究植株生长速率和成熟期株高性状发育对外源GA₃的响应及主茎纵向细胞的形态学变化, 分析两类突变体与各自野生型之间的内源赤霉素含量差异。结果表明, 外源GA₃(40 mg L^-1)对半矮杆和矮杆突变体的作用效果明显不同, GA₃处理后半矮杆突变体植株在不同测定时段的平均生长速率达到2.76 cm d^-1, 而矮杆突变体的平均生长速率仅为0.92 cm d^-1, 而且成熟期半矮杆突变体植株的平均高度、主茎平均节间长度与节间纵向细胞长度均显著超过对照, 外源GA₃能够恢复其正常的野生型株高表型; 而矮杆突变体较对照的上述3项增幅均明显小于半矮杆型, 外源GA₃不能恢复其正常的野生型株高表型。说明半矮杆突变体的植株生长对外源GA₃有明显响应, 为GA₃敏感型突变体; 而矮杆突变体仅在生育前期对外源GA₃有一定程度响应, 为GA₃钝感型突变体。半矮杆和矮杆突变体成熟期植株的内源GA₃₊₁含量均显著低于各自野生型品种, 这可能是二者表型矮化的生理原因。

Responses of Plant Growth of Dwarf and Semi-Dwarf Soybean Mutants to Exogenous GA3

Dwarf and semi-dwarf mutants are the valuable materials for investigating plant gene function and developing new crop variety with high seed yield and lodging resistance. In the present study, the developing plants of dwarf (df) and semi-dwarf (sdf) mutants and their wild-types (WTs) in different growth stages were treated with exogenous gibberellin A₃ (GA₃) in order to analyze responses of plant growth rate, plant height, and vertical cell length from the main stem to exogenous GA₃ (40 mg L^-1), as well as the endogenous GA₃₊₁ level differences between two types of mutants and their WTs. The results indicated that the responses of plant growth of the sdf and df mutants to the exogenous GA₃ were significantly different, demonstrating that GA₃ treatment led to the average rate (2.76 cm d^-1) of plant growth of the sdf mutant in different measuring-time intervals to be significantly higher than that (1.10 cm d^-1) of water treatment (control); but the average rate of plant growth (0.92 cm d^-1) of GA₃-treated df mutant was slightly higher than that (0.56 cm d^-1) of control, and moreover df mutant plants in the prophase of entire growth period only had a little response to exogenous GA₃. In addition, after GA₃ treatment the average plant height, internode length, and vertical cell length of the internode on the main stem of sdf mutant were much higher than those of df mutant, verifying the exogenous GA₃ treatment could recover plant height phenotype of WT-sd in sdf mutant, while not recover that of WT-d in df mutant. The node number on the main stem of two types of mutants was almost no response to GA₃. Based on above results we think that sdf is a GA₃-sensitive soybean mutant, and df is a GA₃-insensitive soybean mutant. Furthermore it was found that the endogenous GA₁₊₃ levels in sdf and df mutant plants were remarkably lower than that in their WT plants, which may be the physiological cause of dwarfism for sdf and df mutants.