The stages of fertilization process in the plants
The fertilization process in the plants
The fertilization process is a process after the pollination process , and it is the process of fusion of the nucleus of the male cell ( the pollen grains ) with the nucleus of the female cell ( the ovum ) to form the zygote .
The flowers are the reproductive structures of angiosperms , They vary in the methods of reproduction , The process of fertilization in plants occurs when the gametes in haploid conditions meet to create a zygote which is diploid .
After the pollination process , the pollen grains sticks on the stigma which secretes sugary solution , then the pollen grain germinates forming a pollen tube which contain 2 male nuclei .
The pollen grains germinates after the carpel is pollinated , the pollen tube emerges and grows , it extends through the style till it reaches the ovule inside the ovary through the micropyle .
The pollen tube does not reach the ovary in a straight line , and there are two types of nuclei which are the vegetative tube and generative nuclei of the pollen grain that pass into the pollen tube .
The pollen tube grows through the style and curls to the bottom of the ovary and then near the receptacle , The pollen tube breaks into the ovule through the micropyle and then to the micropyle bursts into the embryo sac .
The end of the pollen tube degenerates ? In the embryo sac , the male nucleus fuses with the nucleus of the ovum ( the egg cell ) and forms a fertilized ovum which is known as a diploid zygote , This process is known as true fertilization or syngamy .
The other male gamete or nucleus enters into the embryo sac , and it fuses with the secondary nucleus which gives a triploid nucleus that called the primary endosperm nucleus , and it becomes a food source for the growing embryo .
The process of nuclear fission , where there is formation of primary endosperm nucleus is called triple fission , and the zygote undergoes successive divisions to form the embryo inside the ovule .
The ovule develops and becomes the seed while the ovary develops and becomes the fruit , and the fruits differ from each other according to the nature of the ovary .
If the ovary contains one ovule , it will give a fruit with a single seed as olives and peaches , and if the ovary contains many ovules , it will give a fruit with many seeds as the beans and the peas , In case of fruits with multiple seeds , multiple pollen grains are necessary to fertilize with each ovule .