The tetrasporophyte wrapped by callose is of simultaneous type.

四呈四面型，被胼胝壁所包围。

These results indicate that callose metabolism is active and very important not only in microsporogenesis but also in microgametogenesis in rice.

营养细胞的细胞中继续积累胼胝，花粉熟对胼胝在小孢子发育过程中的功能进行了讨论。