Function and deficiency symptoms of Boron
i. It regulates the development and differentiation of vascular tissues, formation and lignification of cell wall.
ii. It is associated with reproductive phase in plants and under imbalanced nutrition it causes sterility and malformation in reproductive organs, flower, pollen grain,
iii. It is involved in carbohydrate metabolism, particularly in translocation of photosynthates.
iv. It boosts nodulation in legumes, regulates water absorption and is essential for synthesis of ATP, DNA, RNA and pectins.
v. Boron plays an important role in the development and differentiation of tissue, carbohydrate metabolism and translocation of sugar in plants.
As B is highly immobile in plant body, the deficiency first appears on younger growths and the external symptoms are accompanied with histological abnormalities particularly necrosis of phloem. The disorders are given several descriptive names in various crops like:
i. Heart-rot of sugar beet: The young central leaves of the crown do not expand and become severely curled. The petiole and the basal part of the midrib turn brown or black and become very brittle. Older leaves turn yellow with scorched or withered appearance. The entire crown becomes necrotic and starts decaying.
ii. Brown heart of root crops: Brown heart of root crops is characterized by dark spots on the thickest part of the root or splitting at center.
iii. Browning or hollow stem of cauliflower. Leaf margins become chlorotic and curled and lamina becomes brittle. The curd enlarges, turns brown, necrotic and starts decaying. The pith becomes hollow, necrotic and forms a large cavity.
iv. Top sickness of tobacco: The youngest leaves fail to open and remain pale green for some time which afterwards turn necrotic and disintegrate. The older leaves become thicker and very brittle. The auxiliary buds sprout and show same symptoms.
Function and deficiency symptoms of Chlorine
i. During photosynthesis chlorine helps in evolution of oxygen.
ii. It is a part of anthocyanin and affects protein synthesis.
iii. It increases turgor pressure.
Deficiency symptoms appear first as wilted leaves that subsequently can become chlorotic and bronze coloured.
Function and deficiency symptoms of Cobalt
i. Cobalt required for symbiotic and non-symbiotic nitrogen is fixation.
ii. It is a part of vitamin B-12.
Biological nitrogen fixation is reduced.
Function and deficiency symptoms of Sodium
Sodium (non-essential element)
Plants take sodium as a substitute for potash under deficient potash supply.
i. It maintains the osmotic pressure and plays a vital role in halophytes.
ii. It also regulates water uptake by plants. Plants take sodium as a substitute for potash under deficient potash supply.
The size and number of leaves in salt loving plants get reduced.
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