烯效唑对水稻幼苗内源IAA含量的影响

研究了烯效唑对3~H-IAA色氨酸合成3~H-IAA的效率及对IAA氧化酶活性的影响,以探讨烯效唑延缓植物生长的作用机理。结果表明,烯效唑对水稻(Oryza sativa L.)幼苗生长的控制效应与其降低内源IAA含量有关,烯效唑浸种处理降低水稻幼苗内源IAA含量有两条途径,其一是提高水稻幼苗IAA氧化酶活性,增强内源IAA的氧化;其二是阻抑内源IAA的合成。烯效唑除阻抑内源赤霉素的生物合成而延缓作物生长外,通过降低内源IAA水平也可能是其延缓作物生长的一个原因。

EFFECT OF PENTEFEZOL ON THE ENDOGENOUS IAA CONTENT IN RICE SEEDLINGS

Two rice (Oryza sativa L.) cultivars, tall cv. "Taizongyu 65" and dwarf cv."Jiangsu' ai" ,were used in the experiments to study the biological efficacy of pentefezol (S-07) to endogenous IAA in rice seedlings. When rice seeds were soaked in S-07 solution for a period of time, the rice seedlings were dwarfed as the content of endogenous IAA was reduced. The results indicated that S-07 enhanced the activity of IAA-oxidase and reduced the rate of transformation of 3H-tryptophan into H-IAA. Thus the endogenous IAA content of rice seedlings were reduced by S-07 treatment leading to subsequent retardation of the growth rate of seedlings. Moreover the rate of distribution of 3H-IAA in leaves and roots of rice seedlings were also reduced by S-07 treatment.