龙眼幼苗镁素吸收特性研究  

Characteristics of Magnesium Absorption by Longan (Dimocarpus longana. Lour) Seedlings

作　　者：李延[1] 刘星辉[1] 庄卫民[1] 

机构地区：[1]福建农业大学土地与环境学系,福州350002

出　　处：《热带作物学报》2001年第1期56-60,共5页Chinese Journal of Tropical Crops

基　　金：国家自然科学基金(49771053);福建省自然科学基金(F99020);福建省高校测试基金资助项目

摘　　要：龙眼镁素吸收曲线、电子探针分析以及代谢抑制剂对龙眼镁吸收影响等三方面的研究结果表明，龙眼镁素吸收特性取决于介质供镁状况，供镁浓度低（≤０．４０ ｍｍｏｌ／Ｌ）时，龙眼对镁的吸收受代谢控制，属主动吸收；供镁浓度高（＞０．４０ ｍｍｏｌ／Ｌ）时，属被动吸收。 Ｋ＋、Ｃａ２＋对镁的吸收有明显的抑制作用，但其机制并不相同。 Ｋ＋抑制 Ｍｇ２＋的吸收作用不是由于与Ｍｇ２＋竞争载体，而是Ｋ＋引起Ｍｇ２＋载体蛋白发生变构作用；Ｃａ２＋对Ｍｇ２＋吸收的影响可能与膜透性的改变有关。The characteristics of magnesium absorption by longan (Dimocarpus Longana.Lour) seedlings were investigated using hydroponic culture, electron x-ray microanalysis and inhibitors. The results indicated that magnesium absorption by longan seedlings depended on magnesium concentration in solution. When magnesium concentration was below 0.4 mmol/L, magnesium uptake was mediated by metabolism. When magnesium concentration was higher than 0.4 mmol/L, mag- nesium uptake was mainly mediated by non-metabolic factors. The presence of K+ or Ca2+ in the solution significantly depressed the Mg2+ uptake by longan Beedlings. It seemed that the depres- sion of Mg2+ uptake by K+ might not occur at carrier site but at allosteric binding site, and might bring about conformational chances in the carrier. The depression of Mg2+ uptake by Ca2+ might be related to the effect of Ca2+ on membrane permeability and magnesium transportain.

关 键 词：龙眼 吸收特性 镁素 矿物质营养 

分 类 号：S667.2[农业科学—果树学]