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
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
C.
If assertion is true but reason is false
Commenlia produce two types of flowers-
(i) Chasmogamous: These flowers are similar to flowers of other species with exposed anthers and stigma.
(ii) Cleistogamous: These flowers do not open at all. In these flowers, anther and stigmalie close to each other. When anther dehisce in the flower buds, pollen grains come in contact with the stigma to effect pollination. Thus, cleistogamous are invariably autogamous as there is no chance of cross- pollen landing on the stigma.
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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