Life Cycle of Flowering Plant 10th Class|Sporophyte And Gametophyte||Sexual Reproduction in Plants скачать в хорошем качестве

Life Cycle of Flowering Plant 10th Class|Sporophyte And Gametophyte||Sexual Reproduction in Plants

Plants have the kind of lifecycle in which there is alternation of generations. Gametophytes develop within the flowers of the plant. The female gametophyte or embryo sac develops from the megaspore. The ovule (megasporangium) contains a diploid megaspore mother cell. It undergoes meiosis and produces four haploid megaspores. One haploid megaspore survives and divides by mitosis to make eight haploid nuclei. Two nuclei migrate to the centre and fuse to form a fusion nucleus. One nucleus out of the remaining six forms the egg cell. The resulting structure, which contains seven cells: the egg, the five non-functional cells, and the fusion nucleus; constitutes the embryo sac. The male gametophyte or pollen grain develops from the microspore. An anther contains four pollen sacs (microsporangia), each of which contains many diploid the microspore mother cells. Each microspore mother cell undergoes meiosis and produces four haploid microspores. A microspore undergoes mitosis. The resulting two-celled structure is a pollen grain, which is the male gametophyte. One cell in the pollen grain is the tube cell, which will form the pollen tube. The other cell is the generative cell, which will form two sperms. The male gametophytes (pollen grains) contain sperms while the female gametophytes (embryo sacs) contain an egg. For fertilisation of the egg, the pollen grains are transferred from the anther to the stigma of the flower. This is called pollination. Pollination that involves just one flower, or flowers on the same plant is called self- pollination. In contrast, pollination that involves two flowers, of different plants of the same species is called cross-pollination. ➡️Fertilisation When a pollen grain reaches the stigma, its tube cell forms a pollen tube that grows through the stigma and the style. It reaches the ovary and enters the ovule through a small opening called the micropyle. The generative cell of the pollen grain forms two sperms, which enter the embryo sac to reach the egg. One sperm fuses with the egg and forms a diploid zygote. The zygote develops into an embryo. The second sperm fuses with the fusion nucleus and produces a triploid (3n) nucleus. This nucleus then develops into a tissue called the endosperm, which provides nourishment to the embryo. This process of the fusion of two sperms (one with the egg and the other with the fusion nucleus) is called double fertilisation. It is a unique characteristic of flowering plants. #lifecycleoffloweringplantsclass10 #lifecycleoffloweringplants #reproductivepartsoffloweringplants #alternationofgenerationofgenneration10th #doublefertilization10thclas #pollination10thclass #pollinationandtypesofpollination #Sporophyteandgametophytegeneration10thclass #malereproductivepartsofflowers #Femalereproductivepartsofflowers #megasporesandmicrospores10thclass #MaleGametophyteofplant10thclass #femalegematophyteofplants10th #embyrosacoffloweringplants10thclass