Unisexuality of flowers prevents from Biology Sexual Reproducti

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 Multiple Choice QuestionsMultiple Choice Questions

51.

An example of a seed with endosperm, perisperm and caruncle is 

  • Cotton

  • coffee

  • lily

  • lily

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52.

Which one of the flowing pairs of plants structures has haploid number of chromosomes?

  • Megaspore mother cell and antipodal cells

  • Egg cell and antipodal cells

  • Nucellus and antipodal cells

  • Nucellus and antipodal cells

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53.

Unisexuality of flowers prevents

  • autogamy, but not geitonogamy

  • Both geitonogamy and xenogamy

  • geitonogamy, but not xenogamy

  • geitonogamy, but not xenogamy


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.

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54.

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 brings about opening of the pollen tube

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55.

Importance of day length in flowering of plants was first shown in 

  • Lemna

  • tobacco

  • Cotton 

  • Cotton 

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56.

Male gametes in angiosperms are formed by the division of

  • microspore

  • generative cell

  • vegetative cell

  • vegetative cell

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57.

Which one of the following is surrounded by a callose wall?

  • Microspore mother cell

  • Male gamete

  • Egg

  • Egg

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58.

Parthenocarpic tomato fruits can be produced by

  • Removing androecium of flowers before pollen grains are released

  • Treating the plants with low concentrations of gibberellic acid and auxins

  • Raising the plants from vernalized seeds

  • Raising the plants from vernalized seeds

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59.

Long filamentous threads protruding at the end of a young cob of maize are

  • anthers

  • styles

  • ovaries

  • ovaries

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60.

Conifers differ from grasses in the

  • production of seeds from ovules

  • lack of xylem tracheids

  • absence of pollen tube

  • absence of pollen tube

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