水稻根表胶膜浸提中根内元素溢出与浸提条件优化研究

Elements Leakage from Roots in Extracting Iron Plaque on the Rice Root Surface and Optimization of Extraction Conditions

浸提剂浸提水稻根表胶膜是研究根表胶膜形成及生态环境效应技术之一。DCB(柠檬酸钠-碳酸氢钠-连二亚硫酸钠)和ACA(抗坏血酸-柠檬酸钠-乙酸钠)是二种稻根胶膜浸提剂。研究结果表明,ACA浸提稻根溶液中钾离子浓度很低,不足DCB浸提剂的1%,说明ACA浸提剂对根细胞的损伤较小。ACA浸提水稻根表铁、锰、磷元素效率大于DCB,而且ACA浸提剂不含硫,浸提液能同时测定硫,便于研究硫对水稻根胶膜形成及效应。可见,ACA浸提方法总体优于DCB。ACA法的最佳浸提条件为:1g鲜根放入ACA浸提剂(抗坏血酸3.0g,0.3molL-1柠檬酸钠40ml,10%乙酸钠(pH5)5ml),振荡平衡时间2h。

Extracting elements from iron plaque of root surface of rice is a common technique to study the formation of iron plaque on root surface and its ecological significance. DCB （dithionite-citrate-bicarbonate） and ACA （ascorbic-citrate-acetic） were used to extract elements from iron plaque on root surface. The present study results showed that potassium concentration was significant lower in ACA-extractable solution than in DCD-extractable solution, less than 1% of DCD-extractable solution, which suggested that ACA extract solution caused less damage to root cells compared to DCB extract solution. The ACA solution had a higher extracting efficiency of Fe, Mn, P than DCB solution. Moreover, as ACA extract solution does not contain sulfur, the sulfur in solution could be simultaneously determined for investigating effect of sulfur on iron plaque formation and their ecological significance. So the ACA was rflore suitable for extraction of iron plaque than DCB. The optimum extraction conditions of ACA method was recommended as bellow： reagents of 3.0 g ascorbic, 40ml 0.3 tool L^-1 sodium citrate and 5ml 10% sodium acetic, the root fresh weight of 1 g, extraction time of 2 h.