Plant Growth and Development

Auxin can be bioassayed by

1. potometer
2. lettuce hypocotyl elongation
3. Avena coleoptile curvature
4. hydroponics.

What causes a green plant exposed to the light, on only one side, to bend towards the source of light as it grows?

1. Light stimulates plant cells on the lighted side to grow faster.
2. Auxin accumulates on the shaded side, stimulating greater cell elongation there.
3. Green plants need light to perform photosynthesis.
4. Green plants seek light because they are phototropic.

Typical growth curve in plants is

1. stair-steps shaped
2. parabolic
3. sigmoid
4. linear.

Dr. F. Went noted that if coleoptile tips were removed and placed on agar for one hour, the agar would produce a bending when placed on one side of freshly-cut coleoptile stumps. Of what significance is this experiment?

1. It made possible the isolation and exact identification of auxin.
2. It is the basis for quantitative determination of small amounts of growth-promoting substances.
3. It supports the hypothesis that IAA is auxin.
4. It demonstrated polar movement of auxins.

A few normal seedlings of tomato were kept in a dark room. After a few days they were found to have become white-coloured like albinos. Which of the following terms will you use to describe them?

1. Mutated
2. Embolised
3. Etiolated
4. Defoliated

Which one of the following growth regulators is known as 'stress hormone'?

1. Abscisic acid
2. Ethylene
3. GA3
4. Indole acetic acid

During seed germination its stored food is mobilized by

1. ABA
2. gibberellin
3. ethylene
4. cytokinin.

The pineapple which under natural condition is difficult to blossom has been made to produce fruits throughout the year by application of

1. NAA, 2,4-D
2. Phenyl acetic acid
3. Cytokinin
4. IAA, IBA.

Which of the following best illustrates "FEEDBACK" in development ?

1. As tissue (X) develops, it secretes something that induces tissue (Y) to develop
2. As tissue (X) develops, it secretes something that slows down the growth of tissue (Y)
3. Tissue (X) secretes RNA which changes the development of tissue (Y)
4. As tissue (X) develops, it secretes enzymes that inhibit the development of tissue (Y)

Through their effects on plant growth regulators, what do the temperature and light control in the plants?

1. Apical dominance
2. Flowering
3. Closure of stomata
4. Fruit elongation