AEBI 210 Lecture Notes - Pollen Tube, Pollen, Cotyledon
8 Jan 2013
School
Department
Course
Professor
Document Summary
Phylum anthophyta contains flowering plants, which are the largest plant group. Flowers in 3s, one cotyledon, parallel veins, scattered vascular bundles. Flowers in 4s or 5s, 2 cotyledons, netted veins, vascular bundles in a ring. 4 pollen sacs (microsporangia) have microsporocyctes with tapetum (nutrient tissue) Microsporocytes divide by meiosis into 4 pollen grains (n) Pollen grains have resistant sporopollenin outer walls arising from the tapetum. The intine (inner wall) is made of cellulose and pectin by the pollen cell. Spore cell divides by mitosis into a tube cell and generative cell. The generative cell divides into 2 sperm cells. Pollen grains are released when they are mature by the anther walls splitting. Each ovule is a nucellus with one megasporocyte covered with integument. Ovules are attached to the wall of the ovary placenta. Megasporocyte divide by meiosis into 4 megaspores (n) One megaspore forms a megagametophyte with 8 nuclei by mitosis.
