提高植物体内铁再利用效率的机理

The mechanism of Fe availability and reutilization in higher plants, as affected by nitrogen from (nitrate and ammonium) and exogenous hormone, was studied in nutrient solution under controlled conditions. Apart from the biochemical and physiological assays, the isotopic techniques and centrifugation method were used in this study. The results showed: (1) Compared with nitrate supply, ammonium improved 15 and 5 percentage of Fe reutilization in bean and maize, respectively; (2) Compared with nitrate treatment, ammonium application decreased 0.2~0.5 pH unit of leaf apoplast, and increased significantly active Fe concentration; (3) The decrease of apoplast pH induced by ammonium was the one of main reason leading to higher percentage of Fe2+ of total Fe in roots fed with ammonium than that of nitrate treatment; (4) Exogenous hormone such as ethylene and zetin could increase Fe availability in young leaf of plants and improve Fe nutrition of plants. In summary, the main mechanism which ammonium ameliorated Fe nutritional status of higher plants was concluded as following: ammonium supply led to the decrease of apoplast pH in leaf and root, the increase of Fe bioavailability and reutilization efficiency

应用营养液培养方法，通过研究（1）铵态氮、硝态氮对玉米和菜豆根、叶细胞原生质膜上ATP酶活性、铁跨膜运输、铁的活化、质外体PH和体内铁再利用的影响；（2）遮光和乙烯对ダ弦镀欣刍幕罨驮倮玫挠跋欤教痔岣咧参锾迥谔倮眯实幕怼⒏闱迤涞骺氐墓丶蹋⑻岢隼弥参镒陨砬绷唇饩鋈碧侍獾纳镅揪逗拖嘤Φ呐┮档骺卮胧