str of pollen grain
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structure of pollen grain:
1. pollen grains develop from the diploid microspore mother cells in pollen sacs of anther
2. pollen grain is haploid, unicellular, uninucleate oval shaped structure.
3. pollen grain is a double layered sporoderm-outer exine and inner intine.
a. exine: it is the outer, thick and resistantnt layer. it is composed of sporopollenin which provides resistance to a pollen grain from physical and biological decomposition.
b. intine: it is the inner layer of sporoderm which is composed of cellulose and pectin.
At certain places the exine remains thin. the thin areas are known as germpore.
in monocots, there is only one germpore for pollen grain(uniporate) while in dicots there are three germ pores (triporate)
pollen grain or microspore is the first cell of male gametophyte or immature male gametophyte.
the branch dealing with the study of pollen grain characteristics is known as palynology.
insect disseminated pollen grains have a covering of yellow sticky substance called pollenkitt. the surface is otherwise spiny.
internally the pollen grain has
1. tube or vegetative cell with degenerating nucleus, vacuolate cytoplasm rich in starch and unsaturated oils and
2. one generative cell(60%) or two male gametes derived from it.
1. pollen grains develop from the diploid microspore mother cells in pollen sacs of anther
2. pollen grain is haploid, unicellular, uninucleate oval shaped structure.
3. pollen grain is a double layered sporoderm-outer exine and inner intine.
a. exine: it is the outer, thick and resistantnt layer. it is composed of sporopollenin which provides resistance to a pollen grain from physical and biological decomposition.
b. intine: it is the inner layer of sporoderm which is composed of cellulose and pectin.
At certain places the exine remains thin. the thin areas are known as germpore.
in monocots, there is only one germpore for pollen grain(uniporate) while in dicots there are three germ pores (triporate)
pollen grain or microspore is the first cell of male gametophyte or immature male gametophyte.
the branch dealing with the study of pollen grain characteristics is known as palynology.
insect disseminated pollen grains have a covering of yellow sticky substance called pollenkitt. the surface is otherwise spiny.
internally the pollen grain has
1. tube or vegetative cell with degenerating nucleus, vacuolate cytoplasm rich in starch and unsaturated oils and
2. one generative cell(60%) or two male gametes derived from it.
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