5,6-二氯吲哚乙酸对水稻幼苗芽鞘向地性的影响

5,6-Cl_2-IAA可以诱导水稻芽鞘产生斜向地性生长。其倾斜角度与外加5,6-Cl_2-IAA的剂量呈线性关系,其反应具有特异性(IAA,6-BA,ABA和BR均不能诱导这种反应)。反应可在2～3h后产生,它可作为5,6-Cl_2-IAA的生物检定依据。切除芽鞘顶尖或外加TIBA对这一反应无明显影响,另外乙烯生物合成抑制剂AVG也不能消除5,6-Cl_2-IAA诱导的斜向地性生长。

Effect of 5,6-Cl_2-IAA on Plagiogravitropism of Rice Coleoptile

Experiments were conducted with rice seedlings to determined the effects of a new auxin, 5,6-Cl_2-IAA, on the gravitropism of rice coleoptile. The results showed that 5,6-Cl_2-IAA induced plagiogravitropism in growing coleoptile of rice seedlings and the angle of inclination increased with the increase in dosage of 5, 6-Cl_2-IAA applied. Other known hormones, like IAA, 6-BA, ABA, GA_3 and epibrassinolide cannot cause plagiogravitropism, indicating the specificity of the response. Neither TIBA (an inhibitor of polar transport of IAA) nor decapitation, of coleoptile could counteract the effect of 5,6-Cl_2-IAA on plagiogravitropism in growing coleopfile of 4-day-old light-grown rice seedlings. In addition, AVG (an inhibitor of ethylene production) also could not overcome the plagiogravitropism induced by 5,6-Cl_2-IAA. These results suggested that the action of 5,6-Cl_2-IAA on the plagiogravitropism of rice coleoptile was independent of endogenous IAA or ethylene.