烯效唑诱导小麦植株形态变化及其与内源激素的关系

UNICONAZOLE-INDUCED MORPHOLOGICAL CHANGE AND ITS RELATION TO ENDOGENOUS HORMONES IN WHEAT SEEDLNGS

小麦种子用1mg·L-1的烯效唑浸种，其幼苗茎秆矮化粗壮，叶色浓绿，根系发达。处理植株的内源GA含量剧烈下降，根系中尤为明显。地上部分的IAA含量有较大增高。ZRs含量在幼苗生长前期的地上部分也有增加，但在根系中却稍低于对照。整个植株ABA含量与对照无显著差异。结果表明：烯效唑可能通过改变内源激素水平间的平稳关系而调控植株的形态变化，其中内源IAA／GA比增高是烯效唑诱导小麦矮化和促进根系生长的主要原因。IAA、ZRs的变化对植物横向生长、叶绿素合成也有促进作用。

Wheat (Triticum aestivum cv. Ganchun No. 18) seeds were soaked with 3. 4 μmol/L uniconazole for 18 hours. The soots length of treated plants were about 50% -60% that of the control,but the roots length,the roots and shoots diameter were increased. Leaf chlorophyll level was also stimulated. Quantitative analyses of endogenous GAs, IAA,ZRs and ABA were performed using ELISA technique. The treated plants contained much less GAs than control, and the reduction of GAs in roots were more than in shoots. Endogenous level of IAA in the shoots were increased markedly by uniconazole,ZRs leves were only increased in the shoots of 5-12 days seedlings. No significant differences of IAA and ZRs in roots were observed. Levels of ABA were similar between the treated plants and control. Our results indicate that regulation of uniconazole to the morphological changes of wheat seedlings may be mediated by the change of endogenous hormonal balances. The high IAA/GAs ratio is a major reason for uniconazole-induced stem reduction and root growth. Changes of IAA and ZRs levels in the treated wheat seedlings have effects of stimulating transverse growth and chorophyll synthesis.