Unisexuality of flowers prevents from Biology Sexual Reproduction in flowering Plants Class 12 Nagaland Board
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Sexual Reproduction in flowering Plants

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Biology

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Biology

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CBSE Gujarat Board Haryana Board

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Class 10 Class 12

Unisexuality of flowers prevents

  • autogamy, but not geitonogamy

  • Both geitonogamy and xenogamy

  • geitonogamy, but not xenogamy

  • autogamy and geitonogamy


A.

autogamy, but not geitonogamy

The transfer of pollen from the anther to stigma is called pollination. Autogamy also called self-pollination involves the transfer of pollen grains on one flower to the stigma of the same flower. Self-pollination occurs only in bisexual or hermaphrodite flowers.

Geitonogamy involves the transfer of pollen grains from a male flower to the stigma of the female flower of the same plant. Thus, geitonogamy operates only in monoecious plants ie, the plants having male and female flowers on different places. 

Allogamy or xenogamy knew as cross-pollination involves the transfer of pollen grains of the male flower to the stigma of the gentically different female flower. It takes place via, various agencies like wind, water, insects etc.

The transfer of pollen from the anther to stigma is called pollination. Autogamy also called self-pollination involves the transfer of pollen grains on one flower to the stigma of the same flower. Self-pollination occurs only in bisexual or hermaphrodite flowers.

Geitonogamy involves the transfer of pollen grains from a male flower to the stigma of the female flower of the same plant. Thus, geitonogamy operates only in monoecious plants ie, the plants having male and female flowers on different places. 

Allogamy or xenogamy knew as cross-pollination involves the transfer of pollen grains of the male flower to the stigma of the gentically different female flower. It takes place via, various agencies like wind, water, insects etc.

556 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
2359 Views

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

C.

nutrition
1827 Views

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

A.

ovary
1446 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
1265 Views