Mineral Nutrition

| 185

MØLÝBDËÑÜM:

Plants obtain it as molybdate ions (MoO2

2+).

01

These enzymes participate in nitrogen cycle &

nitrate reductase nitrogen fixation. (AIPMT 1995)

03

It is a component of many enzymes such as nitrogenase

and nitrate reductase.

02

ÇHLØRÏÑË:

It is absorbed as

chloride anion (Cl^– )

It is essential

for the water-

splitting reaction

in photosynthesis

that leads to oxygen

evolution.

Along with Na⁺

& K⁺, it helps in

determining the

solute concentration

and the anion-

cation balance in

cells.

DËFÏÇÏËÑÇÝ SÝMPTØMS ØF ËSSËÑTÏÅL ËLËMËÑTS



Deficiency of an essential element causes retarded growth.



The morphological changes due to deficiency or absence of an element

are called deficiency symptoms.



The deficiency symptoms include chlorosis, necrosis, stunted growth,

premature fall of leaves and buds, and inhibition of cell division.



Deficiency symptoms vary from element to element.



If the elements are relatively immobile and are not transported out of

the mature organs, the deficiency symptoms appear first in the young

tissues. S and Ca are part of the structural component of the cell and

hence are not easily released.



The plant parts that show the deficiency symptoms depends on the

mobility of the element. For elements that are actively mobilised and

exported to young developing tissues, the deficiency symptoms appear

first in the older tissues, e.g.: nitrogen, potassium, magnesium deficiency

symptoms are visible first in the senescent leaves.