黄瓜、番茄和大豆对缺铁胁迫适应性反应的差异

THE DIFFERENCE OF IRON DEFICIENCY INDUCED ADAPTABLE REACTION AMONG CUCUMBER,TOMATO AND SOYBEAN

黄瓜、番茄和大豆同是双子叶植物，缺铁诱导的适应性机制都属于机理Ｉ，但是它们在适应缺铁胁迫的具体反应上却各有不同。黄瓜、蕃茄缺铁时主要表现为近根尖处膨大、变粗，根毛增多，发育成具有转移细胞特征，并主动向外分泌大量Ｈ＋，使根系对Ｆｅ（Ⅲ）还原能力显著增强，从而提高了根际中铁的有效性。大豆则主要是依靠根尖膨大、变粗，表皮、皮层中积累大量酚类物质来还原难溶性Ｆｅ３＋化合物。植物基因型之间对缺铁胁迫的这种反应上的差异，给铁高效基因型筛选和遗传育种工作提供了广阔的前景。

Although cucumber,tomato and soybean as dicots have been previously classified as the same type of plant(namely mechanismⅠ plant) according to their reaction to iron deficiency,actually their specific reactions to iron deficiency stress were different respectively.Under iron deficiency condition cucumber and tomato significantly increased their iron reducing capacity by root tip swelling,root hair increasing,epidermal transfer cell formation.They actively increased H + secretion.As a result,their rhizospheic iron availability was increased.In contrast,soybean mobilizes rhizospheic sparingly soluble ferric oxide mainly by root tip swelling and by accumulation of phenolic materials in epidermis and cortex.The difference of iron deficiency induced stress reaction between different plant genotypes open a broad prospect for selection and breading of high iron efficient plant species.