Stages of Ovule and Gametophyte Development in Phalaenopsis.

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Time after Pollination Ovary and Megagametophyte Microgametophyte
unpollinated inner carpel walls appressed to each other, meristematic protuberances present but quiescent mature, 2-celled pollen grains contained in the pollinia
2 days hair cell growth from inner ovary epidermis begins, cell division begins pollen hydrated
4 days protuberances develop pollen begind to germinate, vacuoles visible in pollen grains
1 week placentae (carpels?) separate vegatative and generative nucleii move into pollen tubes
2 weeks hair cells fill ovary locule, first branching of meristematic protuberances pollen tubes enter ovary (10 days)
4 weeks further branching of meristematic protuberances many pollen tubes in ovary
5 weeks ovule primordia obvious, but no long file of cells inside and no archesporial cell
6 weeks archesporial cell present. ovule primordia begin to bend pollen tubes reach ovary bottom
6-7 weeks integuments are initiated, outer first at bend in ovule
7 weeks further development of the integuments pollen tubes change direction of growth to reorient towards ovules. Growth along inner epidermis
8 weeks megaspore mother cell formed, suspended in early prophase. Inner integument halfway up m.m.c.
10 weeks inner integuments sealed and outer integuments almost equal in length. Nucellar cells compressed. Meiosis begins. generative cell divides to form two sperm cells (9-10 weeks), pollen tubes at ovule area
11 weeks Meiosis continues and finishes, outer integuments reach fully extended length pollen tubes in between ovules
12 weeks 2-nucleate to mature embryo sac (11-13 weeks population of ovules is undergoing megaspore to mature embryo sac development) as embryo sacs mature, they are fertilized by pollen tubes
14 weeks mature embryo sacs or fertilized embryo sacs with 2-celled embryos only