meg·a·spo·ro·gen·e·sis  (měg'ə-spôr'ə-jěn'ĭ-sĭs, -spōr'-)  n. pl. meg·a·spo·ro·gen·e·ses (-sēz) The formation of megaspores. |
| megasporogenesis (měg'ə-spôr'ə-jěn'ĭ-sĭs) Pronunciation Key
The formation of megaspores inside the ovules of seed plants. A diploid cell in the ovule, called a megasporocyte or a megaspore mother cell, undergoes meiosis and gives rise to four haploid megaspores. In most plants, only one of the megaspores then goes on to develop into a megagametophyte within the ovule, while the other three disintegrate. In the ovules of angiosperms, megasporogenesis takes place within a structure called a nucellus, and it is the megaspore farthest from the micropyle of the ovary that survives. |