The ‘triple response to mechanical stress’ is related to the plant growth regulator:
1. Ethylene
2. ABA
3. Auxin
4. Cytokinin

To render the cells of abscission layer more sensitive to ethylene, an aging leaf produces less and less:
1. Cytokinin
2. Auxin
3. Gibberellin
4. ABA

The newly discovered PGR brassinosteroids have effects qualitatively similar to:
1. Auxins
2. Gibberellins
3. Cytokinins
4. Ethylene

The plant hormones that are produced by wounded plants and play a key role in controlling plant defences against herbivores as well as responsible for enchanting fragrance of jasmine are:
1. Brassinosteroids
2. Strigolactones
3. Jasmonates
4. Auxins

The most important colors in regulating photomorhogenesis in plants are:
1. Violet and Yellow
2. White and Black
3. Green and Orange
4. Red and Blue

Blue light photoreceptors in plant do not regulate:
1. Phototropism
2. Light induced opening of stomata
3. Light induces slowing of hypocotyls elongation
4. Seed germination

The biologically active form of the phytochrome is:
1.${\mathrm{P}}_{\mathrm{r}}$
2. ${\mathrm{P}}_{\mathrm{fr}}$
3. Both
4. None

When lettuce seeds illuminated by red light are then exposed to far red light:

1. ${\mathrm{P}}_{\mathrm{r}}$ is converted to ${\mathrm{P}}_{\mathrm{fr}}$ and germination is inhibited
2. ${\mathrm{P}}_{\mathrm{r}}$ is converted to ${\mathrm{P}}_{\mathrm{fr}}$ and germination is initiated
3. ${\mathrm{P}}_{\mathrm{fr}}$ is converted to ${\mathrm{P}}_{\mathrm{r}}$ and germination is inhibited
4. ${\mathrm{P}}_{\mathrm{fr}}$ is converted to ${\mathrm{P}}_{\mathrm{r}}$ and germination is initiated

Light passing through the green leaves of canopy trees above a seed:
1. stimulates its germination
2. inhibits its germination
3. does not affect its germination
4. causes abnormal germination in the seed

Etiolated seedlings become normal when exposed to:
1. Blue light
2. Green light
3. Red light
4. Far red light