蚕豆胚珠发育过程中淀粉动态的观察

蚕豆胚珠发育过程中淀粉动态变化如下:1.发育早期,整个胚珠中未见淀粉粒。其后首先在合点区出现淀粉,而后从合点向珠孔逐渐扩大分布范围。2.珠心和内、外珠被中均含有淀粉粒,尤以内珠被的淀粉增长迅速,数量多、个体大。受精后,内珠被解体,淀粉出现在外珠被细胞中,推测营养物质可通过整个胚囊表面进入其中。3.合点与胚囊之间的珠心细胞特化或长形。可能有助于营养物质进入胚囊。4.功能大孢子中贮存丰富的淀粉粒,它和珠心细胞一起是胚囊发育时的营养来源。5.卵细胞受精后,所含淀粉粒的数量和大小明显增长,随着合子和胚细胞的分裂,其中贮存的淀粉逐渐被消耗,到多细胞球形胚时完全消失。6.胚乳核周围始终未出现淀粉粒。7.胚器官分化之后,子叶和胚轴等处逐渐出现淀粉粒,其中生长活跃的结构如生长点、维管束等不贮存淀粉。8.子叶中的淀粉粒含量迅速增加,颗粒特大,是种子内营养物质的最终贮存场所。

OBSERVATIONS ON THE DYNAMICS OF STARCH DURING OVULAR DEVELOPMENT IN Vicia faba L.

The dynamics of starch during ovular development in Vicia faba has been investigated by the PAS reaction,the results are summarized as follows; 1. No starch reaction was found at the initial stage of ovular development. As the ovule develops starch grains appeared first in the ehalazal region, and then extended toward the micropylar end. 2.Starch grains were present in nucellus, inner and outer integuments, especially the quantity and size of starch grains in the inner integument around the embryo sac increased rapidly, at anthesis it seems that the nutrients were absorbed from adjacent tissue via entire surface of embryo sac. 3. Some specialised nucellar cells between the vascular bundle and the chalazal end of embryo sac were often present and elongated, this might facilitate nutrient absorption of embryo sac throughchalazal end. 4. A large amount of starch deposit found in functional megaspore and nucellar cells are presumably as the nutrient source in the developmental process of embryo sac. 5. After fertilization, the starch within zygote increased obviously in size and content, and completely disappeared at later stage of proembryo. 6. There was no starch in endosperm at any developmental stage. 7. After differentiation of embryo, the starch deposit reappeared gradually within cotyledon, embryonalaxis and etc. it's content and size increased rapidly within cotyledon.