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501 questions in this collection · Page 5 of 51
Question 41 of 501
📘 CLASS XII
Sexual Reproduction In Flowering Plants
In which of the following plants does Polyembryony commonly occur?
In many Citrus and Mango varieties, nucellar cells develop into embryos. Occurrence of more than one embryo in a seed is referred to as polyembryony.
Question 42 of 501
📘 CLASS XII
Sexual Reproduction In Flowering Plants
Removal of anthers from a flower bud before dehiscence is called:
If the female parent bears bisexual flowers, removal of anthers from the flower bud before the anther dehisces is necessary. This step is referred to as emasculation.
Question 43 of 501
📘 CLASS XII
Sexual Reproduction In Flowering Plants
The innermost wall layer of a microsporangium is usually:
The microsporangium is generally surrounded by four wall layers. The innermost wall layer is the tapetum.
Question 44 of 501
📘 CLASS XII
Sexual Reproduction In Flowering Plants
Which cell of the pollen grain has abundant food reserve and a large irregularly shaped nucleus?
The vegetative cell is bigger, has abundant food reserve and a large irregularly shaped nucleus.
Question 45 of 501
📘 CLASS XII
Sexual Reproduction In Flowering Plants
The generative cell of a pollen grain is:
The generative cell is small and floats in the cytoplasm of the vegetative cell. It is spindle shaped with dense cytoplasm and a nucleus.
Question 46 of 501
📘 CLASS XII
Sexual Reproduction In Flowering Plants
Pollen viability in Rice and Wheat is approximately:
In some cereals such as rice and wheat, pollen grains lose viability within 30 minutes of their release.
Question 47 of 501
📘 CLASS XII
Sexual Reproduction In Flowering Plants
Which family typically maintains pollen viability for months?
In some members of Rosaceae, Leguminoseae and Solanaceae, they maintain viability for months.
Question 48 of 501
📘 CLASS XII
Sexual Reproduction In Flowering Plants
A multicarpellary, apocarpous gynoecium is found in:
The pistils may be free (apocarpous) as in Michelia. Papaver has a syncarpous pistil.
Question 49 of 501
📘 CLASS XII
Sexual Reproduction In Flowering Plants
The protective envelopes of the ovule are called:
Each ovule has one or two protective envelopes called integuments.
Question 50 of 501
📘 CLASS XII
Sexual Reproduction In Flowering Plants
The mass of cells enclosed within the integuments having abundant reserve food material is:
Enclosed within the integuments is a mass of cells called the nucellus. Cells of the nucellus have abundant reserve food materials.