植物生長抑制劑DOWCO 242對於大豆初期生長及其莖內PEROXIDASE, IAA-OXIDASE活性影響之研究

Abstract

DOWCO 242是一種新合成的植物生長抑制劑，以低濃度的DOWCO 242 (10 ppm)處理大豆種子3日，幼苗的生長即可受到極大的抑制：節間長度縮短、植凍高度降低，維管束細胞的分化延遲；此種抑制作用是DOWCO 242促進了IAA-oxidase，Peroxidase的活性，及降低莖內可抽取的IAA與GA3含量所致。 DOWCO 242對於植物生長的抑制效應，隨著幼苗生長日數的增加有逐漸減小的趨勢，此時幼苗莖內IAA-oxidase，Peroxidase活性相對的降低，而IAA及GA3的含量則相對地增加，最使使幼苗生長速率恢復。

Tetraisopentyl axnmonium bromide, designated DOWC0 242, is a newly synthetic growth retarding chemical. After the treatment of soybean seeds with 1, 5, 10, 25, 50 ppm of DOWCO 242, there was no effect on germinability, but the growth of radicl and shoots of the seedlings were retarded, and the higher the concentration of DOWCO 242 used, the larger the degree of inhibition demonstrated. As a result of treatment with 10 ppm DOWCO 242, the hypocotyl became shorter because of the inhibition of cell elongation of cortex and pith. DMC0 242 reduced the content of extractable IAA and GA3 in the stem of soybean seedlings, but promoted the activities of IAA-oxidase and peroxidase, that caused the reduction of plant height and retardation of differentiation of vascular elements in the stem. As the age of seedlings increased, the inhibitory effects of DOWCO 242 were weakened. After 10th days of growth, the growth rate of 10 ppm treated seedlings were gradually recovered; there were the declination of IAA-oxidase and peroxidase activities, and the restoration of IAA and GA3 content in the stem. Finally, the growth substances content, oxidase activities and growth rate were all recovered.