Effects Of Water-soluble Organic Matter On The Growth And The Element Uptake Of Rice

This study was conducted to investigate the effect of the water-soluble organic matter (WSOM) extracted from peat and rice straw on the growth and the element uptake of rice by water culture. The effect of excess copper and cadmium on the absorption of other nutrient elements by the rice was also studied.The results showed that the two WSOMs promoted the tillage and the growth of the rice, and mitigated the poisonous symptoms induced by Cd and Cu. The growth of the root was promoted more significantly than that of the above-ground part. The WSOM extracted from rice straw has shown a stronger effect than that extracted from peat. The two WSOMs had no significant effect on the photosynthesis characteristics of the leaves.The WSOMs not only increased the uptake of Cd, but also promoted the translocation of Cd form root to stem and leaf when Cd was added. Under the conditions that excessive Cu was incorporated, however, the effect of the WSOMs on the uptake and translocation of Cu was more complicated.The addition of Cd significantly enhanced the absorption of Ca, Mg and Fe while inhibited that of Cu and Mn by the root. The excess of Cu significantly promoted the uptake of Fe by roots, but inhibited the translocation of Fe from root to the above-ground part. The content of K, Zn and Mn in the above-ground part was decreased by the excessive Cu. When excessive Cd or Cu was added, the WSOMs had some effects on the absorption and translocation of other elements which were quite complicated.