子叶和未来称为下胚轴的主轴延长。
并多数发生于于叶与下胚轴的深层。胚性细胞团周围细胞退化，使其与周围组织之间形成间隙。
The surrounding cells of the embryonic cell groups degenerate, such there is the space between the groups of cell and the surrounding tissue.
本文就高浓度生长素对菜豆下胚轴切段伸长的抑制作用与乙烯释放的关系进行了讨论。
The relationship between the inhibition of hypocotyl segments elongation at high concentration of IAA and the IAA-induced ethylene production was discussed.
应用推荐