Question
Answer
- Upon falling on the stigma, the pollen grain uses the nutrients from the stigma to germinate and from a pollen tube.
- The pollen tube grows down the style.
- The tube nucleus takes a leading position followed by the generative nucleus.
- The generative nucleus divides by mitosis to form two male gamete nuclei;
- The nuclei passes through the micropyle into the ovary.
- On arrival at the embryo sac ,the tube nucleus degenerates one male gamete nucleus fuses with the polar nuclei to form a triploid primary endosperm .
- The other male gamete nucleus fuses with the functional egg to form a diploid zygote. This is known as double fertilization.
- The integument becomes the testa while the zygote is differentiated into plumule and radical.
- The primary endosperm becomes the endosperm tissue.
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