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Zinc deficiency occurs when plant growth is limited because the plant cannot take up sufficient quantities of this essential micronutrient from its growing medium. It is one of the most widespread micronutrient deficiencies in crops and pastures worldwide and causes large losses in crop production and crop quality. Almost half of the world's cereal crops are grown on zinc-deficient soils; as a result, zinc deficiency in humans is a widespread problem.〔 ==Symptoms== Visible deficiency symptoms include:〔 *Chlorosis - yellowing of leaves; often interveinal; in some species, young leaves are the most affected, but in others both old and new leaves are chlorotic;〔〔 *Necrotic spots - death of leaf tissue on areas of chlorosis; *Bronzing of leaves - chlorotic areas may turn bronze coloured; *Rosetting of leaves - zinc-deficient dicotyledons often have shortened internodes, so leaves are clustered on the stem; *Stunting of plants - small plants may occur as a result of reduced growth or because of reduced internode elongation; *Dwarf leaves ('little leaf') - small leaves that often show chlorosis, necrotic spots or bronzing; *Malformed leaves - leaves are often narrower or have wavy margins. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Zinc deficiency (plant disorder)」の詳細全文を読む スポンサード リンク
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