FUNCTIONS IN PLANTS

Chlorine is readily taken up by plants in the electrically charged form as chloride ion  (Cl ). Although chlorine occurs in plants as chlorinated organic compounds , chloride is the major form within plants, where it is bound only loosely to exchange sites or is a highly mobile free anion in the plant water. As an essential element, chlorine has several biochemical and physiological functions within plants.
 Chloride appears to be required for optimal enzyme activity of asparagine synthethase , amylase , and ATPase . In photosynthesis, chloride is an essential cofactor for the activation of the oxygen-evolving enzyme associated with photosystem II . Chloride may bind  to the polypeptides associated with the water-splitting complex of photosystem II, and it may stabilize the oxidized state of manganese by acting as a bridging ligand . Chloride concentrations required for biochemical functions are relatively low in comparison to concentrations required for osmoregulation

DIAGNOSIS OF CHLORINE STATUS IN PLANTS

1
SYMPTOMS OF DEFICIENCY
Visible deficiency symptoms for chlorine have been well characterized in several crops by growth of plants in chlorine-free nutrient solutions . The most commonly described symptom of chlorine deficiency is wilting of leaves, especially at the margins. As the deficiency becomes more severe, the leaves may exhibit curling, shriveling, and necrosis . Roots of chlorinedeficient plants have been described as stubby with club tips. Deficiency symptoms of chlorine are not commonly exhibited visually in most crops growing in the field, but symptoms are sometimes observed in wheat and coconut palm (Cocos nucifera L.). In chlorine-deficient wheat, the symptoms are expressed as chlorotic or necrotic lesions on leaf tissue . These symptoms that result from chlorine deficiency have been named ‘Cl-deficient leaf spot syndrome’ . It has also been shown that bromide  does not substitute for chloride in the prevention of deficiency symptoms . In coconut palm, the symptoms are exhibited as wilting and premature senescence of leaves, frond fracture, and stem cracking and bleeding .

2 
SYMPTOMS OF EXCESS
Chloride toxicity symptoms have been observed in many field, vegetable, and fruit crops . Curling of the leaf margins, marginal leaf scorch, leaf necrosis, and leaf drop are typical symptoms. Older leaves are usually the first to exhibit symptoms that may progress upward, affecting the entire foliage. Dieback of the terminal axis and small branches may occur in cases of severe toxicity. These symptoms of chloride toxicity occur in the absence of sodium, but they are also similar to symptoms of salt toxicity that occur when chloride is accompanied by sodium. Crops and cultivars within crops vary widely in tolerance to high levels of chloride, with corn being relatively tolerant to chloride  compared to soybean (Glycine max Merr.) .

What is fear chlorion crops?
Tomato,Tobacco,SugarCane,Apple,Grape,suger beet,orange,Water melon