Abstract: The esterase isozyme in the root tissues and the contents of endogenous hormones such as Z, ZR, IAA, GA, and ABA, in the different parts of root system for the creeping-roofed and noncreepingrooted alfalfa plants were measured at various growing stages (May 16th, June 25th, August 9th and Sept.21th).The dynamics of esterase isozyme and endogenous hormones in the creeping-rooted and noncreeping rooted alfalfa plants and the relationship between the formation and growth of adventitious bud and the hormone contents were compared and analysed.It is showed that the esterase isozyme bands in the root system of creeping-rooted and noncreepingrooted alfalfa are obviously different, the band numbers of esterase isozyme in the creeping-rooted alfalfa plant is significantly higher than those in the noncreeping-rooted alfalfa plant.It means that the esterase isozyme in the alfalfa root system is consistent with the gene expression of its creeping-rooted character.The analysis results also showed that the peak contents of Z+ZR, GA₃ and IAA in the crown and root tissues of creeping-rooted and noncreeping-rooted alfalfa plants are at the vigorous growing stage (June 25th and August 9th).The ABA content increases along with the continuous growth and development.The seasonal change of Z+ZR, IAA and GA, in the creeping-rooted plant is different from that in the noncreeping-rooted plant, while those in the noncreeping-rooted plants of two different genotypes are similar.The ratio of IAA/(Z+ZR), or (IAA + GA₃)/(Z + ZR) in the root system of creeping-rooted plant are lower than that of noncreeping-rooted plant.It is concluded that the initiation and growth of stem primordia is associated with the contents of Z+ZR, IAA and GA₃.The distribution of endogenous hormones in the different root tissues of creeping-rooted alfalfa is uneven.The formation of expansion in horizontal root of creeping-rooted alfalfa is related with the significant increase of ondogenous GA₃.

Key words: Creeping-rooted alfalfa, Endogenous hormone, Esterase isozyme

摘要： 在植物生长发育的不同阶段(5/16、6/25、8/9、9/21)测定了根蘖苜蓿和非根蘖苜蓿植株根组织中的酯酶同工酶及根系不同组织部位中五种内源激素(Z、ZR、IAA、GA₃和ABA)含量,并比较、分析根蘖植株与非根蘖植株酯酶和内源激素动态及根蘖植株根蘖芽的形成和生长与激素的关系。研究结果表明,根蘖与非根蘖苜蓿植株根组织酯酶同工酶带数明显不同,根蘖苜蓿植株明显高于非根蘖苜蓿植株2～4条谱带,这说明苜蓿根组织酯酶同工酶可能与苜蓿根蘖性状的基因表达有关。根系中内源激素分析结果表明,根蘖与非根蘖苜蓿植株根颈和根组织中(Z+ZR)、IAA、GA₃含量均在植物生长发育旺盛时期(6/25、8/9)最高。ABA含量随植株生长发育而呈上升趋势。根蘖植株的(Z+ZR)、IAA、GA₃和ABA含量在整个生育期中的变化趋势与非极蘖植株不同,而来源于根蘖型品系中非根蘖植株与当地品种主根植株的变化规律相似。根蘖苜蓿植株根系中IAA/(Z+ZR)低于非根蘖植株。苜蓿植株根系中内源激素(Z+ZR)、IAA、GA₃含量与苜蓿根蘖芽形成和生长有关。根蘖植株根系内不同组织部位内源激素分布不一致,根蘖苜蓿植株水平根膨大与内源激素GA₃含量显著增加有关。

关键词: 根蘖苜蓿, 内源激素, 酯酶同工酶