英语语法分析

The integument grew fast and overgrew the nucellus.

珠被生长较快，并逐渐包围珠心。

The nucellus is usually degraded and absorbed as the endosperm develops.

珠心通常在胚乳发育时被分解和吸收。

The female archesporium differentiates from the single cell under the epidermis of nucellus.

雌性孢原处于珠心表皮之下，为单细胞。