Morphological and Physiological Responses to Iron Deficiency in Crops

缺鐵植株之形態變化為幼葉黃化，生長受到抑制，根伸長停止根尖直徑增加，產生多數之側根及根毛且有轉運細胞的發生。生理方面，雙子葉及部份單子葉植物根表皮細胞可增加氫離子釋放，分泌酚類化合物及增進細胞膜還原能力。經由這類適應機制，植株得以增加鐵之吸收，缺鐵植株地上部可能經由篩管傳達信息至根部產生上述高效鐵利用生理反應。 Iron-deficient plants manifested a number of common morphological changes include growth. inhibition, chlorosis of young leaves, arrest of root elongation, enlargement of the diameter of root tips, radical increase in the number of lateral roots and root hairs and the formation of transfer cells. Physiologically, in the rhizodermal cells of dicotyledons and some monocotyledons, a sharp upsurge of proton release and of phenolic compounds secretion were evident. The reducing capacity of plasmalemma was also found to be strengthened. These coping measures adopted by the affected plants for the enhancement of iron absorption are highly effective physiological responses that seems triggered by the distress signals conveyed to the roots from the above-ground portion by way of the phloems