What does the filiform apparatus do at the entrance into ovule? from Biology Sexual Reproduction in flowering Plants Class 12 Nagaland Board
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Sexual Reproduction in flowering Plants

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CBSE Gujarat Board Haryana Board

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Class 10 Class 12

What does the filiform apparatus do at the entrance into ovule?

  • It helps in the entry of pollen tube into a synergid

  • It prevents entry of more than one pollen tube into the embryo sac

  • It brings about opening of the pollen tube

  • It guides pollen tube from a synergid to egg


A.

It helps in the entry of pollen tube into a synergid

In most cases, the mature embryo sac contains 7-cells and nuclei. The cells are arranged egg apparatus (two synergid cell and one egg cell,) a central cell with two nuclei and antipodal cells ( 3 in number). The synergid cells occur laterally to the egg cell. These cells are characterised by finger- like projections called filiform apparatus towards the micropylar end. Fill form apparatus is formed due to invaginations of cell wall into the protoplasm and is made up of pectocellulosic fibres evolved in the non-cellulosic sheath. Secretion of chemotactic substances for the attraction of pollen tube during fertilisation is the function of synergies. One synergid becomes degenerate during pollen entry into the embryo sac and thus, provides a way for the entry of pollen tube into the embryo sac.

In most cases, the mature embryo sac contains 7-cells and nuclei. The cells are arranged egg apparatus (two synergid cell and one egg cell,) a central cell with two nuclei and antipodal cells ( 3 in number). The synergid cells occur laterally to the egg cell. These cells are characterised by finger- like projections called filiform apparatus towards the micropylar end. Fill form apparatus is formed due to invaginations of cell wall into the protoplasm and is made up of pectocellulosic fibres evolved in the non-cellulosic sheath. Secretion of chemotactic substances for the attraction of pollen tube during fertilisation is the function of synergies. One synergid becomes degenerate during pollen entry into the embryo sac and thus, provides a way for the entry of pollen tube into the embryo sac.

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The fertilization occurs in the :
  • ovary
  • ovule
  • embryo sac
  • nucellus.

A.

ovary
1446 Views

The female gametophyte of a typical dicot at the time of fertilization is:
  •  8-celled
  • 7-celled
  • 6-celled
  • 4-celled

B.

7-celled
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The innermost layer of anther is tapetum whose function is :
  • dehiscence
  • mechanical
  • nutrition
  •  protection.

C.

nutrition
1827 Views

Simultaneous meiotic division of microspore mother cells leads to :
  • tetrahedral tetrad
  • linear tetrad
  •  isobilateral
  • decussate tetrad.

A.

tetrahedral tetrad
1487 Views

In a bisexual flower when the gynaecium matures earlier than anther, it is called as :
  • protandry
  • protogyny
  • herkogyny
  • None of the above.

B.

protogyny
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