Study of V.S. of anatropous ovule through a permanent slide/relevant chart
Practical Notebook Biology Standard XII
Biology
Answeres
Practical Notebook
Standard XII
Class-12th
science
5. Study of V. S. of anatropous ovule through a permanent slide / relevant chart.
Ovule (megasporangium) is enclosed in the ovary.
There may be one or many ovules in an ovary.
Alm:
Study of anatropous ovule and functions of its various parts. . The ovule in which micropyle, chalaza, and funicle are not in one straight line and integuments run parallel to funicle is called as anatropous ovule. It is also called an inverted ovule and is the most common type of ovule, in angiosperms, The ovule shows two main parts - body and funicle. Body The body shows two integuments originating from the base of the ovule reaching up to the tip of the ovule.
The tip shows a small cleft, left by two integuments called a micropyle. The integuments enclose a mass of fertile, parenchymatous, diploid cells called nucellus. There is only one fertile cell located more or less in the center of the nucellus but towards the micropylar end of the ovule, this is called the megaspore mother cell. It finally develops into only one female gametophyte (embryo sac). In the monosporic embryo sac, the female gametophyte.
It is 8 - a nucleated and 7 - celled structure. Game Female gametophyte consists of egg apparatus, 2 - polar nuclei, and 3 - antipodal cells. Egg The egg apparatus is located closer to the micropylar end of the embryo sac. It consists of the central haploid egg cells and 2 supporting laterally placed haploid synergids. Mat In a mature female gametophyte, the 2 polar nuclei fuse to form the diploid secondary nucleus (definitive nucleus). Figure: Fig. V. S. of anatropus ovule
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