鹤顶兰胚珠发育过程及受精前后同工酶的变化

The Relationship Between Ovule Development and Isozymes after Pollination in Phaius tankervilliae (Aiton) Bl

通过光学显微镜观察发现:鹤顶兰[Phaius tankervilliae(Aiton)Bl.]授粉后10d胎座出现指状突起,20d形成胚珠原基,24d大孢子母细胞发生,30d功能大孢子形成,41d发育为成熟的八核胚囊,而后完成双受精发育成早期球形胚。用聚丙烯酰胺凝胶电泳的方法研究鹤顶兰从指状突起出现到早期球形胚形成的全过程中酯酶(Est)、酸性磷酸酶(Acp)的变化发现:这一过程中Est表达有7个同工酶位点,Acp有5个同工酶位点,两者均在八核胚囊时期变化最显著。Est-7和Acp-4在整个发育过程中都有表达;在八核胚囊时期特异表达的位点有Est-4和Acp-3;而Acp-2只在这一时期不表达。Est-1在八核胚囊时期和大孢子母细胞减数分裂中期表达。授粉后Est和Acp的酶位点变化说明与胚珠发育相关的一系列基因表达有时序性,位点Est-4、Acp-2和Acp-3是否直接参与了八核胚囊发育的控制,有待于进一步的研究。

Under microscope, the nucellar filament of Phaius tankervilliae （Aiton） B1. could be observed on 10^th day after pollination, archesporial cell on 20^th day, megasporocyte on 24^th day, the functional megaspore on 30^th day; and 8-nucleate embryo sac on 41^th day. And then double fertilization finish and early globular embryo emerge. The researches on isozymes indicated that some varieties of isozyme loci present during the embryo development. There are 7 esterase （Est） loci and 5 acid phosphatase （Acp） loci during the periods between nucellar filament and early globular embryo; Both of Est and Acp appeared the most diversity in the stage of 8-nucleate embryo sac. Est-7 and Acp-4 always express in the whole developmental stages , and Est-4 and Acp-3 just express in the stage of 8-nucleat embryo sac of Phaius tankervilliae （Aiton） B1. , but Acp-2 express in all developmental stages except the 8-nucleat embryo stage. Est-I only express in the stage of 8-nucleat embryo sac and metaphase of meiosis. Further studies should be done to confirm if Est-4, Acp-2 and Aco-3 could regulate the development of 8-nucleat embryo sac.