at maturity

详细解释:【经】 到期

例句：

An opening at definite places at maturity to release or expose the contents, such as seeds from a fruit or pollen from an anther.开裂，裂开到达成熟期时在一定的位置裂开的口子，以释放或显露出内含物，如从果实的裂口处释放出来的种子或从花粉囊中散发出的花粉