The pollen grains of rice and wheat lose their viability inminutes of their release
30
10
60
90
A.
30
Pollen viability is the period for which pollen grains retain the ability to germinate. It is little in flowers which are pollinated in bud condition. Eg, it is 30 minutes in rice and wheat. It depends upon environmental conditions of temperature and humidity.
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
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
Sporopollenin is a constituent of pollen exine. It can be degraded by the action of
enzymes
high temperature
strong acids
cannot be degraded
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
