When the plants are grown in magnesium deficient but urea rich soil, the symptoms expressed are:
1. yellowish leaves
2. colourless petiole
3. dark green leaves
4. shoot apex die.

Select the mismatch.

(1) Frankia                      Alnus

(2) Rhodospirillium            Mycorrhiza

(3) Anabaena                   Nitrogen fixer

(4) Rhizobium                 Alfa-fa

Which is essential for the growth of root tip?
(1) Zn

(2) Fe

(3) Ca

(4) Mn

In which of the following, all three are macronutrients?
(1) Iron, copper, molybdenum

(2) Molybdenum, magnesium, manganese

(3) Nitrogen, magnesium, phosphorus

(4) Boron, zinc, manganese

During biological nitrogen fixation, inactivation of nitrogenase by oxygen poisoning is prevented by

(1) leghaemoglobin

(2) xanthophyll

(3) carotene

(4) cytochrome

Auxin can be bioassayed by

1. Avena coleoptile curvature

2. hydroponics

3. potometer

4. lettuce hypocotyl elongation

Minerals known to be required in large amounts for plant growth include

1. Phosphorus, potassium, sulphur, calcium

2. calcium, magnesium, manganese, copper

3. potassium, phosphorus, selenium, boron

4. magnesium, sulphur, iron, zinc

Deficiency symptoms of nitrogen and potassium are visible first in

1. senescent leaves

2. young leaves

3. roots

4. buds

The most abundant intracellular cation is

1. Na⁺

2. Ca²⁺

3. H⁺

4. K⁺

The first stable product of fixation of atmospheric nitrogen in leguminous plants is

1. ${\mathrm{NO}}_2^{-}$

2. ammonia

3. ${\mathrm{NO}}_3^{-}$

4. glutamate