Question

Identify number of wrong statements from the following
A) Mn deficiency causes interveinal chlorosis starting first in old leaves
B) Calcium deficiency causes interveinal chlorosis starting first in young leaves
C) S deficiency causes chlorosis starting first in young leaves.
D) Mg deficiency causes chlorosis starting first in old leaves.
E) N 2 deficiency causes marginal chlorosis

Answer 1

Hint:- The term chlorosis refers to a condition in which the plants lack chlorophyll. Chlorophyll is the pigment required for green coloration of the leaves in plants. So, in plants with chlorosis, the leaves turn yellow and pale. Iron and manganese are the elements required by the plants to form chlorophyll and thus, impart green color to the leaves and perform photosynthesis.

Complete step-by-step solution:-
Chlorosis is caused due to nutritional deficiency in plants. The main element deficiency leading to chlorosis of leaves is iron. Mn deficiency usually occurs along with iron deficiency. This leads to lack of chlorophyll in the leaves. Due to the absence of the green pigment, the leaves turn yellow. This yellowing of leaves is interveinal and usually starts in younger leaves and then moves on to the older leaves. The midribs remain unaffected in manganese deficiency. The deficiency of Ca leads to necrosis of the tissues in growing parts of the plants and thus, leads to the stunted growth of plants. Sulphur deficiency in plants results in yellow or pale green leaves. This yellowing is experienced by the younger leaves of the plant. Magnesium deficiency in plants also results in chlorosis but here, the yellowing begins in the older leaves first. The deficiency of nitrogen in plants leads to reduced size of the leaves. Chlorosis is present throughout the leave and not marginal.
Thus, statements A, B, and E are incorrect.

Note:- To avoid chlorosis in plants, they have to be provided with sufficient amounts of water, so that they can pick up the required amount of nutrients. The change in the colour of the leaves is irreversible. The yellow leaves can’t be turned into green again. Poor watering and lighting are the commonest causes leading to chlorosis.