Abstract:

The relationship between the effect of exogenous jasmonic acid (JA) on the induction of secondary laticifer differentiation and the distribution of JA in the seedling of Hevea brasiliensis Mull. Arg. was investigated with the aid of experimental morphological and radioisotope technique. Most radioactivity of 3H-JA sustained in treated site within one hour while no radioactivity was detected in new shoot and the radioactivity in upper leaf was much less than that in the parts below the treated site, suggesting that JA was mainly transported downwards in the shoot of H. brasiliensis. Mechanical wounding hindered the en-trance of exogenous JA remarkably while held back the entered JA to the regions around wounded site. The effect of exogenous JA and mechanical wounding on the induction of the secondary laticifer differen-tiation was limited to treated site where high level of JA was expected. Mechanical wounding reduced the effect of exogenous JA on the differentiation of secondary laticifer, which could be ascribed to the hindrance of mechanical wounding to the entrance of exogenous JA. It was concluded from the combined data that a high accumulation of JA was required for inducing the secondary laticifer differentiation in H. brasiliensis.

机械伤害和外施茉莉酸对巴西橡胶树次生乳管分化的局部效应及其与茉莉酸分布的关系
田维敏 史敏晶 于凤义  吴继林  郝秉中  崔克明

(1. 北京大学生命科学学院, 北京 100871;
2. 中国热带农业科学院橡胶栽培研究所热带作物栽培生理学农业部重点开放实验室, 儋州 571737;
3. 华南热带农业大学农学院, 儋州 571737; 4. 中国农业科学院原子能利用研究所, 北京 100094)
摘要: 采用同位素示踪技术和实验形态学的方法揭示茉莉酸在木本植物巴西橡胶树(Hevea brasiliensis Mull.
Arg.)中的分布和运输的特点,并分析其与机械伤害和外施茉莉酸对巴西橡胶树次生乳管分化的诱导效应之间的关系。外施的茉莉酸进入体内后，在较长时间内大部分集中在施用部位。机械伤害阻止外施的茉莉酸进入体内，同时，又使进入的茉莉酸阻滞在受伤部位的附近。与茉莉酸在草本植物中可以向上和向下运输的情况不同，茉莉酸在木本植物巴西橡胶树中主要是向下运输的。机械伤害和外施茉莉酸对巴西橡胶树次生乳管分化的诱导效应是局部的，只在受伤和施用茉莉酸部位的树皮中诱导次生乳管的形成。机械伤害削弱外源茉莉酸对次生乳管分化的诱导效应，这与机械伤害阻止外源茉莉酸进入有关。研究结果表明,体内高水平的茉莉酸是诱导巴西橡胶树次生乳管分化所必需的。
关键词： 巴西橡胶树； 茉莉酸； 机械伤害； 同位素示踪；乳管分化

通讯作者。E-mail: <ckm@pku.edu.cn>。