Dissolution of different zinc salts and Zn uptake by Sedum alfredii and maize in mono-and co-cropping under hydroponic culture

作     者：Cheng'ai Jiang Qitang Wu Shucai Zeng Xian Chen Zebin Wei Xinxian Long 

作者机构：College of Natural Resources and Environment South China Agricultural University College of Forestry South China Agricultural University 

出 版 物：《Journal of Environmental Sciences》 (环境科学学报（英文版）)

年 卷 期：2013年第25卷第9期

页      面：1890-1896页

核心收录：

学科分类：090706[农学-园林植物与观赏园艺] 0907[农学-林学] 09[农学] 0901[农学-作物学] 

基　　金：supported by the National Natural Science Foundation of China (No. 40571141  410713061) 

主　　题：zinc compounds dissolution co-cropping root exudates hydroponic 

摘      要：Previous soil pot and field experiments demonstrated that co-cropping the hyperaccumulator Sedum alfredii with maize increased Zn phytoextraction by S. alfredii and decreased Zn uptake by maize shoots. This hydroponic experiment was conducted to investigate whether the facilitation of Zn phytoextraction by S. alfredii resulted from improved dissolution in this co-cropping system and its relation to root exudates. S. alfredii and maize were mono-and co-cropped （without a root barrier） in nutrient solution spiked with four Zn compounds, ZnS, ZnO, Zn3（PO4）2 and 5ZnO·2CO3·4H2O （represented as ZnCO3 ） at 1000 mg/L Zn for 15 days without renewal of nutrient solution after pre-culture. The root exudates were collected under incomplete sterilization and analyzed. The results indicated that the difference in Zn salts had a greater influence on the Zn concentration in maize than for S. alfredii, varying from 210-2603 mg/kg for maize shoots and 6445-12476 mg/kg for S. alfredii in the same order： ZnCO3 〉 ZnO 〉Zn3（PO4）2 〉 ZnS. For the four kinds of Zn sources in this experiment, co-cropping with maize did not improve Zn phytoextraction by S. alfredii. In most cases, compared to co-cropped and mono-cropped maize, mono-cropped S. alfredii resulted in the highest Zn2＋ concentration in the remaining nutrient solution, and also had a higher total concentration of low molecular weight organic acids （LMWOA） and lower pH of root exudation. Root exudates did partly influence Zn hyperaccumulation in S. alfredii.