磷对水稻镉的亚细胞分布及化学形态的影响

Effects of phosphorus on subcellular distribution and chemical speciation of cadmium in rice

为了探讨磷对水稻耐镉性的影响,采用盆栽实验,以沈农315(耐性)和花粳1417(敏感性)水稻为研究对象,对分蘖末期水稻根系及茎叶中镉的亚细胞分布以及化学形态进行比较分析。结果表明:增施磷肥显著降低了两品种水稻的镉含量,沈农315根系镉含量明显高于花粳1417,茎叶镉含量低于花粳1417;两品种各部位细胞壁镉的分配比例随磷的增加而明显增加,细胞器镉的分配比例逐渐降低。镉的化学结合形态整体上呈现为氯化钠提取态>醋酸提取态>去离子水提取态>乙醇提取态>盐酸提取态,其中醋酸提取态所占比例随磷增加而增加,沈农315和花粳1417的增幅分别为19.70%~31.32%、10.05%~16.36%,氯化钠提取态显著降低,降幅分别为23.38%~40.11%、22.55%~39.56%。由此说明,增施磷肥能有效增加水稻对镉的耐受性,且不同品种表现不同。

To determine the effect of phosphorus on cadmium tolerance in rice, a pot experiment was carried out with two genotypes of rice：Shennong315, a cadmium-tolerant variety, and Huajing1417, a cadmium-sensitive variety. The subcellular distribution and chemical form of cadmium in these two varieties were analyzed at the end of the tillering stage of rice. The results showed that the application of phosphate fertilizer significantly reduced the cadmium content of the two cultivars. The content of cadmium in roots of Shennong315 was higher than that of Huajing1417, and the content of cadmium in stem and leaves was lower than that of Huajing1417. The proportion of cadmium in the cell wall of the cultivars increased significantly with increase in phosphorus, and the proportion of cadmium in the organelle gradually reduced. The chemical binding morphology of cadmium overall proceeded in the order sodium chloride extract acetic acid extract distilled water extractethanol extracthydrochloric acid extract. The proportion of acetic acid extract increased with increase in phosphorus. Shennong315 increased by 19.70%-31.32% and Huajing1417 increased by 10.05%-16.36%. The proportion of sodium chloride extract was significantly decreased with increase in phosphorus. Shennong315 fell by 23.38%-40.11% and Huajing1417 fell by 22.55%-39.56%. Therefore, the application of phosphate fertilizer can effectively increase the tolerance of rice to cadmium, and different varieties have different performances. This study provides a scientific basis for the use of phosphorus to alleviate cadmium toxicity in rice.