Multiple Choice QuestionsSporopollenin is a constituent of pollen exine. It can be degraded by the action of
enzymes
high temperature
strong acids
cannot be degraded
The pollen grains of rice and wheat lose their viability inminutes of their release
30
10
60
90
After doble fertilization, a mature ovule has
1 diploid and 1 haploid cell
1 diploid and 1 triploid cell
2 haploid and 1 triploid cell
1 haploid and 1 triploid cell
B.
1 diploid and 1 triploid cell
Double fertilization is the fusion of two male gametes with a female gametophyte. It is found only in Angiosperms.
In angiosperms, the pollen tube bursts open in one of the two synergids to release the two male gametes. One male gamete fuses with the egg to form a diploid zygote and is known as generative fertilization. The second male gamete descends down and fuses with the diploid secondary nucleus of the central cell to form a triploid primary endosperm cell and is known as vegetative fertilization.
After double fertilization, mature angiospermous ovule contains one diploid cell (zygote) and one triploid cell (endosperm).
Which of the following is not true for inbreeding?
It causes inbreeding depression after a few generations
It always increases the productivity.
It is used to produce a pure line.
It leads to homozygosity
The given figure shows L.S of the seed of maize. What do A, B, C and D represent?
A : endosperm, B : scutellum, C : plumule, D : coleoptile
A : scutellum, B : pericarp, C : radicle, D : coleoptile
A : endosperm, B : scutellum, C : radicle, D : coleorrhiza
A : scutellum, B : pericarp, C : plumule, D : coleorrhiza
Assertion : Commelina shows cleistogamy.
Reason : This reduces chances of inbreeding.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
What is the characteristic of tapetum
It does not store food.
It is multi-nucleated.
It is multi-layered structure.
It nourishes the megaspore
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