外源生长素对烟草(Nicotiana tabacum L.)小孢子早期胚胎发生的影响

Influence of Exogenous Auxin on Microspore Embryogenesis in Tobacco

烟草(N icotiana tabacum L.)小孢子胚胎发生系统,不仅可以提供大量可供处理的小孢子胚,还由于小孢子胚胎发生的不同步性,可同时提供从2-3细胞原胚到分化胚一系列胚胎以供研究。利用这一便利系统,探讨了外源生长素处理对小孢子胚胎发育的影响。使用3种浓度的IAA:1、3、10μm o l/L,分别对不同发育时期烟草小孢子胚进行了处理,结果发现,对不同发育时期的小孢子胚,生长素处理的效果明显不同。外源生长素对胚胎发生有促进作用,表现为2-3细胞比例与非处理组相比升高,而当小孢子发育到小球形胚后,加入外源生长素对小孢子胚的进一步发育却表现出明显抑制作用。这说明在小孢子胚胎发育过程中早期和晚期发育对生长素的需求是不同的,且对生长素的敏感程度亦不同。反映了生长素调控机制在两个不同发育时期的差异。

Microspore embryogenesis system of tobacco （Nicotiana tabacurn L. ） was employed in the experiments, which offered excellent material of embryos at different stages for the test of auxin treatments. When treated with exogenous auxin of diverse concentrations, 1μmol/L, 3μmol/L, 10μmol/L of IAA,embryos at early and later stages showed different responses. Auxin enhanced the formation of 2-3 cell embryos and early globular embryos,but inhibited the formation of later globular embryos and the embryo differentiation. The experiments revealed that two phase, early and later,of embryogenesis showed different sensitivity to auxin treatment ,which reflects different mechanism of auxin regulation in those two developmental processes.