When nitrates are scarce in the soil where legumes are growing:
I. The plants secrete Nod factors that attract Rhizobia to their root hairs.
II. In turn the bacteria secrete flavonoids that stimulate the infection process in the plant.
1. Both I and II are correct
2. Only I is correct
3. Only II is correct
4. Both I and II are incorrect

The uptake of which of the following by a plant contributes maximum to its dry weight:
1. water and minerals through root hairs.
2. water and minerals through mycorrhizae.
3. carbon dioxide by leaves through stoma.
4. sugars in the root hairs.

All the following regarding bacteroid form of Rhizobium are true except:
1. It is a differentiated symbiotic form of nitrogen fixing Rhizobium
2. It is non-motile and non-reproductive
3. It has a more freely permeable membrane than free living Rhizobium
4. It is larger in size than the free living Rhizobium and spherical in shape

What percentage of the dry weight of a plant is made up of organic molecules?
1. 10%
2. 23%
3. 72%
4. 96%

Rhizobium:

It is vital to bubble air into the solute in hydroponic culture to:
1. evenly distribute the dissolved nutrients
2. provide oxygen to the root cells
3. inhibit the growth of fungi
4. inhibit the growth of anaerobic bacteria

More than 90% of the dry weight of plants is due to:

In the symbiotic relationship, rhizobia supply ammonia to the plant and in return receive:
1. Simple sugars
2. Fatty acids
3. Organic acids like malate and succinate
4. Amino acids

Plant growth and development mainly depend on:
1. nitrogen; phosphorus; oxygen
2. potassium; carbon; calcium
3. oxygen; carbon; hydrogen
4. phosphorus; nitrogen; potassium

If the leaves of whole plant show chlorosis, the mineral nutrient most likely to be deficient would be:
1. boron
2. manganese
3. nitrogen
4. calcium