科研之友
微信
新浪微博
Facebook
分享链接
摘要
Organic ligands in soils affect the availability of trace metals such as Zn to plants. This study investigated the effects of two of these ligands, citrate and histidine, on Zn uptake by wheat under hydroponic conditions. Uptake of Zn-65 in the presence of these ligands was compared to uptake in the presence of EDTA at the same free Zn concentration (Zn2+ similar to 50 nM). In the presence of citrate Zn root uptake was enhanced similar to 3.5 times and in the presence of histidine, by a factor of similar to 9, compared to the EDTA treatments. Citrate uptake was slightly reduced in the treatment containing ligands and Zn compared to the treatment containing the same ligand concentration but no Zn. In addition, a higher uptake of Zn than of citrate was observed. This suggests that the enhanced Zn uptake was primarily due to increased supply of Zn2+ by diffusion and dissociation of Zn-citrate complexes at the root surface. Histidine uptake was much higher than citrate uptake and not influenced by the presence of Zn. As histidine forms stronger complexes with Zn than citrate, the results suggest that the enhancement of Zn uptake in the presence of histidine was in part due to the uptake of undissociated Zn-histidine complexes.
- 出版日期2013-11-6
