砷镉复合污染条件下硫对小麦砷镉积累的影响及其生理生化机制

减少农作物可食部位砷镉积累，对保障食品质量安全具有重要意义。研究表明，在植物对砷/镉的吸收与代谢过程中，硫与砷/镉之间存在着显著的相互作用，外源硫的施加可以分别减少砷和镉向植物地上部的转移。然而，在砷镉复合污染条件下，硫是否可以同时降低小麦籽粒中砷镉的含量以及硫对植物砷镉吸收、转运和积累的影响尚未见报道。本项目拟通过水培和土培试验，研究硫对小麦体内砷镉吸收、积累和分布的影响。并从土壤中砷镉的赋存形态及其生物有效性、砷镉在植物组织和细胞水平的分布、砷镉在植物体内存在的化学形态、植物体内非蛋白巯基化合物（半胱氨酸、谷胱甘肽和植物螯合肽）的变化、植物螯合肽合成酶基因和ABCC转运蛋白基因的表达与砷镉积累的关系等方面深入研究硫对小麦砷镉积累的影响机制。

In the interest of better food safety, it is important to reduce arsenic (As) and cadmium (Cd) accumulation in the edible parts of crops and vegetables. Recent studies have showed that sulfur (S) application could alleviate As and Cd toxicity to plants and restrict As and Cd translocation to shoots. However, the effects of S on As and Cd uptake, translocation and accumulation in plants is unknown when the plants grown in soil contaminated with both As and Cd. The influence of S on As and Cd accumulation in wheat grains is unclear so far. In this project, we will study the effects of S on As and Cd accumulation and distribution in wheat plants exposed to As and Cd under hydroponics and pot experiments. Furthermore, we will provide further insights into the physiology and biochemical mechanisms of the influence of S on As and Cd accumulation in wheat plants through 1) study the fractions of As and Cd in the soil and their bioavailability to wheat, 2) determine the As and Cd chemical forms and subcellular distribution in different parts of wheat plants, 3) analyze the relationship between As accumulation, Cd accumulation and phytochelatins concentration in wheat plants, 4) study the role of phytochelatins synthase gene and ABCC transporter gene expression in As and Cd accumulation in wheat plants.