ANGIOSPERM

THE MEGASPOROCYTE (MEGASPORE MOTHER CELL) IN THE FEMALE PLANT UNDERGOES MEIOSIS TO PRODUCE MEGASPORES. THEN THE MEGASPORE UNDERGOES THREE ROUNDS OF MITOSIS, CREATING 8 NUCLEI. THE CELL CLOSEST TO THE MICROPYLE OPENING DIFFERENTIATES INTO THE EGG CELL. WITH TWO SYNERGIDS BY ITS SIDE THAT AID THE POLLEN DOWN THE POLLEN TUBE. THREE ANTIPODAL CELLS FORM ON THE OPPOSITE END OF THE OVULE AND LATER DEGENERATE. THE LARGE CENTRAL CELL OF THE EMBRYO CONTAIN TWO POLAR NUCLEI. 

DURING DOUBLE FERTILIZATION, TWO SPERM NUCLEI  ENTER THE OVULE THROUGH THE POLLEN TUBE THEN THE MICROPYLE. ONE SPERM WILL FERTILIZE THE EGG FORMING A ZYGOTE (DIPLOID). THE OTHER SPERM WILL FUSE WITH TWO POLAR NUCLEI TO FORM THE ENDOSPERM (TRIPLOID) WHICH WILL NOURISH THE DEVELOPING EMBYO. THE ADVANTAGE OF DOUBLE FERTILIZATION IS TO ENSURE THAT THE ENDOSPERM WILL DEVELOP WHERE THE EGG IS FERTILIZED 

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