植物激素在大叶落地生根胎生苗无性繁殖过程中的作用

THE ROLE OF PHYTOHORMONES IN ASEXUAL PROPAGATION IN KALANCHOE DAIGREMONTIANA LEAVES

植物的生长和发育是指未分化的分生组织成为成熟植物组织结构的过程。在这个过程中,生长素和细胞分裂素都扮演着非常重要的角色。由于国内外研究对胎生苗产生过程中,这两种激素的作用存在争议,没有形成一致的结论。而且关于植物激素对大叶落地生根胎生苗无性繁殖的作用还未进行过研究,所以本文对此进行了深入研究。通过施用生长素和细胞分裂素、以及相应的激素抑制剂,统计胎生苗发生的时间、数量和叶幅变化情况。生长素(2,4-D)诱导产生的胎生苗发育不完整,胎生苗很难继续发育成长。而细胞分裂素(6-BA)诱导产生的胎生苗发育完整,能成长为成年植株。生长素和细胞分裂素同时作用时,两者拮抗作用不明显,但以生长素的作用为主。生长素抑制剂(TIBA),不会阻碍胎生苗的产生,但会使叶片发育出现畸形(胎生苗叶片不是对称产生)。细胞分裂素抑制剂(PR)抑制在切割叶片中胎生苗的产生。以完整叶片为外植体,实验结果表明细胞分裂素对控制胎生苗产生时间起决定性作用,经过PR处理的外植体,胎生苗产生所需时间是最短的;以切割叶片为外植体,当抑制细胞分裂素以后(PR)处理,胎生苗就不能产生,强有力的说明了在胎生苗的产生过程中,细胞分裂素是引起胎生苗产生的关键因子。在胎生苗的发育过程中,首先起作用的激素也是细胞分裂素,6-BA处理的胎生苗叶片直径明显大于其他处理。

Plant growth and development means meristem that undifferentiated cells becoming mature plant tissues.Two plant hormones,cytokinin and auxin,are known to play important roles in controlling meristems activity.As the role of hormones in plantlet primordium development on leaf explants is controversial,a thorough ex-periment was studied here.2,4-D,6-BA and corresponding hormone inhibitors were used in the experiment,three indicators:the growth time of plantlet shoots,total number of plantlet shoots and the size of plantlet were analyzed with SPSS software.The plantlet induced by 2,4-D was not complete that hard to grow up,while the plantlet induced by 6-BA was robust to grow.The antagonism effect of two phytohormones was not obvious,but 2,4-D played a major role.Auxin inhibitors(TIBA),which not impeded plantlet formation,but could cause deformed plantlet.In contrast,cytokinins inhibitor(PR)was completely inhibited the formant of plantlet in cutting blade.Cytokinins was crucial in control the formation time of plantlet in unbroken leaf explant because the time was shortest under the treatment of PR.The plantlet was completely inhibited after the use of PR in cutting blade explant.These results strongly indicated that cytokinins is the key factor in induce the plantlet formation.As well as in the growth process,cytokinins was the first acting hormone due to the size of plantlet leaves under 6-BA treatment was greater than in the other treatments.