英语语法分析

An extine with its specific pattern had already been formed, when microspores were released from tetrads.

当小孢子从四分体中释放出来，特殊类型的外壁已经形成。

The results showed that the type of microsporic tetrads of the simple flower is belong to tetrahedral type and the mature pollen is two-celled with bristles on the surface.

单瓣紫花木槿的小孢子母细胞经过减数分裂形成四面体状的四分体，成熟花粉是二细胞型花粉，圆球型，表面有刺毛。