161.

What does the filiform apparatus do at the entrance into ovule?

• It helps in the entry of pollen tube into a synergid

• It prevents entry of more than one pollen tube into the embryo sac

• It brings about opening of the pollen tube

• It brings about opening of the pollen tube

Importance of day length in flowering of plants was first shown in 

• Lemna

• tobacco

• Cotton 

• Cotton 

Male gametes in angiosperms are formed by the division of

• microspore

• generative cell

• vegetative cell

• vegetative cell

Which one of the following is surrounded by a callose wall?

• Microspore mother cell

• Male gamete

• Egg

• Egg

Parthenocarpic tomato fruits can be produced by

• Removing androecium of flowers before pollen grains are released

• Treating the plants with low concentrations of gibberellic acid and auxins

• Raising the plants from vernalized seeds

• Raising the plants from vernalized seeds

Long filamentous threads protruding at the end of a young cob of maize are

• anthers

• styles

• ovaries

• ovaries

Conifers differ from grasses in the

• production of seeds from ovules

• lack of xylem tracheids

• absence of pollen tube

• absence of pollen tube

The arrangement of the nuclei in a normal embryo sac in the dicot plants is

• 2+4+2

• 3+2+3

• 2+3+3

• 2+3+3

An enzyme that can stimulate germination of barley seeds is

• α-amylase

• lipase

• protease

• protease

In a cereal grain the single cotyledon of embryo is represented by

• coleorhiza

• scutellum

• prophyll

• prophyll