Mention the difference between passive and active salt absorption.

3

(a)

Write two names for each of the following
(i) Free-living, nitrogen-fixing cyanobacteria.
(ii) Free-living, aerobic, nitrogen-fixing bacteria
(iii) Symbiotic, nitrogen-fixing bacteria.

3

(a)

A section of root nodule of chick-pea plant appears pink
(i) Name the pigment, responsible for pink colour.
(ii) What is the role of this pigment in the nodule formation?
(iii) Explain the process of biological nitrogen-fixation in the root nodules in short.

3

(a)

Describes nitrification along with the equations and the organisms involved in each step.

3

(a)

Name the most crucial enzyme found in root nodules for N₂-fixation. Does it require a special pink coloured pigment for its functioning? Elaborate.

3

(a)

Why is purification of water and nutrient salts, so important in studies involving mineral nutrition using hydroponics?

3

(a)

In what form do plants absorb phosphorus from the soil?Name one cell organelle and one organic molecule that require phosphorus in the cell.List any two phosphorus deficiency symptoms in leaves.

3

(a)

Describe two important functions of each of the elements P, Fe, and Zn in green plants. Mention deficiency symptoms of any two of these elements.

3

(a)

How are the terms critical concentration and deficient different from each other in terms of concentration of an essential element in plants?Can you find  the values of critical concentration and deficient minerals FE and Zn.

3

(a)

Why is that certain plants deficiency symptoms appear first in younger parts of the plant, while in others they do so in mature organs?

3

(a)

A farmer adds/supplies Na, Ca, Mg and Fe regularly to his field and yet he observes that the plants show deficiency of Ca, Mg and Fe. Give a valid reason and suggest a way to help the farmer to improve the growth of plants.

3

(a)

What are two macronutrients which are not obtained through soil as mineral nutrition? What is their importance?

3

(a)

Which enzyme is found in root nodules of leguminous plants? What role does it play?

3

(a)

What are various symptoms of deficiency in plants?

3

(a)

How different essential elements are absorbed by plant?

3

(a)