The condition where anthers and stigma are placed at different positions to prevent autogamy is called:
[Sexual-Reproduction-in-Flowering-Plants] [class-xii]
Correct Option: B
Answer: Heterostyly/Position difference
Explanation: In some other species, the anther and stigma are placed at different positions so that the pollen cannot come in contact with the stigma of the same flower.
The pollen tube enters the ovule through the:
[Sexual-Reproduction-in-Flowering-Plants] [class-xii]
Correct Option: C
Answer: Micropyle
Explanation: Pollen tube, after reaching the ovary, enters the ovule through the micropyle.
Which structure guides the entry of the pollen tube into the synergid?
[Sexual-Reproduction-in-Flowering-Plants] [class-xii]
Correct Option: C
Answer: Filiform apparatus
Explanation: Many recent studies have shown that filiform apparatus present at the micropylar part of the synergids guides the entry of pollen tube.
The process of removal of anthers from a bisexual flower bud is called:
[Sexual-Reproduction-in-Flowering-Plants] [class-xii]
Correct Option: B
Answer: Emasculation
Explanation: Removal of anthers from the flower bud before the anther dehisces... is referred to as emasculation.
Bagging is done to:
[Sexual-Reproduction-in-Flowering-Plants] [class-xii]
Correct Option: B
Answer: Prevent contamination of stigma with unwanted pollen
Explanation: Emasculated flowers have to be covered... to prevent contamination of its stigma with unwanted pollen. This process is called bagging.
Syngamy results in the formation of:
[Sexual-Reproduction-in-Flowering-Plants] [class-xii]
Correct Option: B
Answer: Zygote
Explanation: One of the male gametes moves towards the egg cell and fuses with its nucleus thus completing the syngamy. This results in the formation of a diploid cell, the zygote.
The primary endosperm nucleus (PEN) is formed by the fusion of:
[Sexual-Reproduction-in-Flowering-Plants] [class-xii]
Correct Option: B
Answer: Male gamete and two polar nuclei
Explanation: The other male gamete moves towards the two polar nuclei... and fuses with them to produce a triploid primary endosperm nucleus (PEN).
Which of the following seeds retains the endosperm (albuminous)?
[Sexual-Reproduction-in-Flowering-Plants] [class-xii]
Correct Option: D
Answer: Castor
Explanation: Albuminous seeds retain a part of endosperm... e.g., wheat, maize, barley, castor.
The root tip of a dicot embryo is covered with:
[Sexual-Reproduction-in-Flowering-Plants] [class-xii]
Correct Option: B
Answer: Root cap
Explanation: The root tip is covered with a root cap.
In grasses, the scutellum is situated:
[Sexual-Reproduction-in-Flowering-Plants] [class-xii]
Correct Option: C
Answer: Laterally
Explanation: In the grass family the cotyledon is called scutellum that is situated towards one side (lateral) of the embryonal axis.