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

1. It helps in the entry of pollen tube into a synergid

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

3. It brings about opening of the pollen tube

4. It guides pollen tube from a synergid to egg

Which one of the following is resistant to enzyme action?

(1) Cork

(2) Wood fibre

(3) Pollen exine

(4) Leaf cuticle

Male gametes in angiosperms are formed by the division of:

(1) microspore

(2) generative cell

(3) vegetative cell

(4) microspore mother cell

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

(1) Microspore mother cell

(2) Male gemete

(3) Egg

(4) Pollen grain

What would be the number of chromosomes in the cells of the aleurone layer in a plant species with 8 chromosomes in it synergids ?

(1) 16

(2) 24

(3) 32

(4) 8

Parthenocarpic tomato fruits can be produced by :

(1) removing androecium of flowers before pollen grains are released

(2) treating the plants with low concentrations of gibberellic acid and auxins

(3) raising the plants from vernalized seeds

(4) treating the plants with phenylmercuric acetate.

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

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

(1) 2+4+2

(2) 3+2+3

(3) 2+3+3

(4) 3+3+2

In angiosperms, microsporogenesis and megasporogenesis

(1) occur in anther

(2) form gametes without further divisions

(3) involve meiosis

(4) occur in ovule

Flowers are unisexual in

(1) pea

(2) cucumber

(3) china rose

(4) onion