2:magnified 2 000 times by sem, each pollens are closely linked, there were plasmodesmata between pollens and tapetum, callose accumulated to form callose wall which thicken gradually;
ⅰ -2:扫描电镜2 000倍,各花粉间紧密相连,花粉间及绒毡层间有胞间连丝存在,胼胝质累积形成胼胝质壁并逐渐加厚;
magnified 1 500 times by sem, the plasmodesmata were disappeared, the pollens separated with each other natively, the callose wall dissolved entirely;
ⅲ -2:扫描电镜1 500倍,花粉间胞间连丝消失,各花粉间自然分离,胼胝质壁完全溶解;
the formation of the callose wall occured at the pmc stage.
pmc胼胝质壁的形成是在花粉母细胞时期开始的;