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It may inhibit the absorption of other nutrients: Excess zinc can inhibit the absorption and

transport of other nutrients, leading to mineral imbalances in plants.

16.11. Molybdenum

Molybdenum is a micronutrient required in trace amounts for plants and has important functions

in the plant. The main function of molybdenum is to play a critical role in nitrogen conversion
processes in plants [105]. The function of molybdenum in plants are:

Nitrogen Fixation: Molybdenum plays an important role in nitrogen fixation in plants.
Molybdenum is involved in the structure of enzymes (nitrogenases) that are effective in nitrogen

fixation and helps plants to utilize nitrogen in the atmosphere.

It helps nitrogen fixation by rhizobium bacteria. Root nodule bacteria also require Mo.

Reduction of Nitrate: Molybdenum is also involved in the conversion of nitrate to simpler

compounds, e.g., ammonia, in plants.

Increases the availability of P and S in the soil. Takes part in vitamin synthesis.

16.11.1. Molybdenum Deficiency

Molybdenum deficiency symptoms are often similar to nitrogen deficiency. Older and middle
leaves first undergo chlorosis. In some cases, leaf curling, growth, and flower formation are

restricted.

Problems in Nitrogen Fixation and Nitrate Reduction: Molybdenum deficiency reduces the

efficiency of nitrogen fixation and nitrate reduction in plants. Therefore, nitrogen uptake and

protein synthesis of plants may be affected.

Slow Growth and Development: Molybdenum deficiency can cause slow growth and

development in plants. Leaves of plants may be small and pale in color.

16.11.2. Molybdenum Excess

Toxicity: Excess molybdenum can cause toxicity in plants. High molybdenum levels can cause

spotting and burns on leaves (chlorosis with orange color and pigmentation).

It may inhibit the absorption of other nutrients: Molybdenum excess can lead to mineral

imbalances in plants by inhibiting the absorption and transport of other nutrients.

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