Question

What happens to embryo sac after fertilisation

Answer 1

The structure of embryo sac before and after fertilisation, embryo and endosperm development and transfer cell distribution in Phaseolus radiatus were investigated using light and transmission electron microscopy. The synergids with distinct filiform apparatus have a chalazal vacuole, numerous mitochondria and ribosomes. A cell wall exists only around the micropylar half of the synergids. The egg cell has a chalazally located nucleus, a large micropylar vacuole and several small vacuoles. Mitochondria and plasrids with starch grains are abundant. No cell wall is present at its chalazal end. There are no plasma membranes between the egg and central cell in several places. The zygote has a complete cell wall, abundant mitochondria and plastids containing starch grains. Both degenerated and persistant synergids might serve as a nutrient supplement to proembryo. The wall ingrowths will occur in the central cell, basal cell, inner integumentary cells, suspenser cells and endosperm cells. These transfer cells may contribute to embryo nutrition at different stages of embryo.