Nutrition

As the phosphate is found in both DNA and RNA hence phosphorus is the pan of both DNA and RNA.

Potassium is macroelement of plants. Deficiency symptoms of K are-mottled interveinal chlorosis appears first in older leaves, marginal or apical yellowing or scorch and curling, die back, bushy habit, shorter internodes, loss of apical dominance, cereals may show lodging, loss of cambial activity, plastid disintegration and increase in rate of respiration.

Chlorosis is a condition in which leaves produce insufficient chlorophyll. As chlorophyll is responsible for the green colour of leaves, chlorotic leaves are pale, yellow or yellow-white. Chlorosis is typically caused when leaves do not have enough nutrients to synthesise all the chlorophyll they need. It can be brought about a combination of factors including a specific mineral deficiency in the soil, such as iron or magnesium.

Denitrification i.e. conversion of fixed nitrates back into the atmospheric nitrogen is carried out by denitrifying bacteria e.g., Pseudomonas
While Nitrosomonas and Nitrococcus convert ammonia into nitrites and Nitrobacter converts nitrites to nitrates

Function of zinc a micronutrient in plant is activation of enzymes. In especially carboxylases, carbonic anhydrases and several other type of dehydrogenases. It maintain normal auxin content in plant. There, it is essential for a large number of metabolic process. Enzyme carbonic anhydrase provide during photosynthesis and evolves the gas during respiration. Deficiency of this element can cause chlorosis of leave shortening of internode. Rosselle of apple and peach, mottled leaf of citrus and white bud of maize diseases in plant are due to the deficiency of nutrient.

Free nitrogen gas, i.e., molecular nitrogen cannot be directly utilised by plants. It has to be fixed into nitrogenous compounds prior to utilisation. Most plants absorb nitrogen in the form of (nitrate) or (ammonium ion). Nitrate is the most important source of nitrogen to the plants. It can accumulate in the cell sap of several plants and take part in producing osmotic potential. However, it cannot be used as such by the plants It is first reduced to nitrite and then to ammonia Ammonia then combines with some organic acids to produce amino acids, which then form various types of nitrogenous compounds.

The denitrification process involves the release of free from its compounds like amino acids. In nitrogen cycle Pseudomonas bacteria are involved in the process of denitrification.

Magnesium is a macro nutrient. Micro nutrients are essential elements that are needed by plants in small amount. They include and . Macro nutrients, on the other hand, are those essential elements that are required by plants in larger amount. The examples include and .