Studies On Physiological Characteristics Of A Rice Dwarf Mutant And Its Regulation

Taking rice(Oryzn Satire L.) variety zhonghua11(ZH11) as control, the plantmorphological, physiological and biochemical characteristics and the regulation ofexogenous growth substances of CA648, a rice dwarf mutant line obtained bytransformation with the plasmid pDs1300 T-DNA into rice variety ZH11, werestudied in the paper. The plants of CA648 were treated with GA₃, IAA, Z and GA₃ atseedlings stage and GA₃ at mid tillering stage, then the biological characteristics wereanalyzed, and endogenous phytohormones, soluble sugar, soluble protein, theactivities of peroxidase and IAA oxidase were also determined. The main results areas follows1. There is no significant differences in the stem length during the seedling stage butthere are significant differences during tillering stage between CA648 and ZH11. Thecontent of endogenous GA₁₊₄ and IAA in CA648 is lower at the seedling stage buthigher at mid tillering stage than that in ZH11.2. After treated with three different plant growth regulators during the seedling period,CA648 plants at 2ed leaf stage was sensitive to the three plant growth regulators, andshowed the most sensitivity towards GA₃. The stem length and the 2ed sheathelongation rate of CA648 were 50.1% and 65.7 % respectively and the correspondingendogenous phytohormonal contents were increased accordingly. The results ofdifferent dosages of GA₃ treatment at different stages indicate that CA648 is a lifeperiod sensitive mutant within the whole life cycle.3. No significant differences of soluble sugar and soluble protein but significantdifferences of photosynthetic indexes, POD activity and IOD activity were observedat the mid tillering stage between CA648 and ZH11. 14d after mid tillering stage,POD activities of CA648 in leaf and stem was 43.0% and 16.8 % higher than that ofZH11. The IOD activities of CA648 in leaves was 77.4 % higher than that of ZH11.4. The plant height and soluble protein in CA648 raised with the concentration of GA₃The POD, IOD activities in leaves of CA648 reduced with the concentration of GA₃,but the POD activity in the stem of CA648 enhanced with the concentration of GA₃.The above results indicate that the morphological differences between CA648 andZH11 are correlated with phytohormones, soluble protein, POD and IOD activities.