The tetrasporophyte wrapped by callose is of simultaneous type.

四分体呈四面体型，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.

营养中继胼胝，花粉成熟对胼胝在小孢子形成和发育过程中功能进行了讨论。