Cotton fibres mainly contains

• cellulose

• glycogen

• protein

• lipid

How many haploid nuclei are present in a mature pollen grain

• One

• Two

• Three

• Four

Sporopollenin 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

Plants with inferior ovary usually bear

• pseudocarps

• berries

• aggregate fruits

• seedless fruits

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