| Along with the development of agriculture, irrigation of agricultural wastewater, fertilization of sludge and phosphatic fertilizer, Cd pollution for farmland soil become more and more serious. In particular, the rice safety is affected by the pollution of paddy field. Cd pollution problem has become a threat to the soil ecological safety and an important factor of restricting the sustainable development of agriculture. How to reduce the infect of Cd on rice become a urgent problems to be solved. Therefore, this article used two copies of rice with different cumulative absorbility of cadmium as experimental material, and researched the influence of the root morphology of rice seedlings, distribution of chemical form of Cd and content of GSH under Cd stress with handling by different concentration of Ca. Main research results are as follows:(1) The root morphology of rice seedlings has different reaction under different concentration of Ca, Cd. Only under the stress of Cd, two copies of root morphologies of rice seedlings shows that low Cd concentration promote root growth, high Cd concentration inhibit the growth. Under the stress of Cd and adding Ca, two copies of root morphologies of rice seedlings shows the situation of increasing first, then decreasing along with the increasing of Ca concentration. There is discrepancy between different materials. The specific performance is as below: Under the stress of Cd, handling with low cadmium (1mg/L) promote the growth of rice seedling root, but If handling with higher cadmium (5mg/L), it obviously retrains rice seedlings, root dry weight, total root root, Surface area and volume number. Whether in low cadmium (1mg/L) or higher cadmium (5mg/L), low concentration of Ca (80,160 mg/L) obviously promote the increasing of root dry weight, rice seedlings, total root surface, root volume, root number. And high concentration of Ca (320mg) inhibit the growth of root. Under the stress of Cd and different concentration of Ca, different under two kinds of rice seedlings, with 0.4 mm diameter than the root, the diameter of than 0.2 mm the root growth..Ca (80mg/L, 160mg/L) could promote growth of rice seedling roots and ease the infect of cadmium to rice. Either handling with Cd alone or with calcium and cadmium, the influence to E2B is significantly greater than Yixiang B, and the indexes of E2B is higher than Yixiang B.(2)With the increasing concentration of the cadmium ion, the total content and different charges of cadmium ion content in two kinds of rice seedlings increased. And the discrepancy was existed between two kinds of rice seedlings. When the concentration of the calcium ion increased in the instances mentioned before, the total content and different charges of cadmium ion content descended firstly and rose after separately. After the change, the significant differences existed in two kinds of rice seedlings. When the leaves and roots of rice seedlings was treated with cadmium ion solution only, the extract of sodium chloride solution and acetic acid solution is advantage form, followed by water, ethanol extract and the hydrochloric acid extract. With the increase of the concentration of the ambient cadmium ion solution, the proportion of preponderant state in the water and ethanol fraction of rice seedlings roots descended, while the proportion of preponderant state rose gradually in the water fraction of rice seedling leaves. Compared with the two kinds of examples, E2B total compared with different chemical form Cd content Cd content than the lower body is sweet B, Ethanol extraction ratio of water, add hydrochloric acid and the highest proportion of extraction, the body is difficult to move the Cd. Under cadmium stress in the amount of the element calcium 80mg/L, 160mg/L after seedling leaves and roots of rice in sodium chloride and acetic acid extraction state extraction is still advantage, followed by water extraction form ethanol extract and configuration, When 80mg/L for calcium concentration or 160mg/L, rice seedlings of ethanol extract roots and water extraction, while the proportion of rice seedlings in leaf extract and water is ethanol extraction proportion of big changes, Rice seedlings and acetic acid hydrochloric acid extraction of increasing proportion of state. When 320mg/L calcium to rice seedlings, instead of the normal amount of cadmium than for calcium, cadmium ethanol and water extraction proportion of state for calcium than normal. Either alone or with calcium cadmium to interact with E2B calcium cadmium and cadmium in chemical form of cadmium effect significantly greater than Yixiang B is.(3) the glutathione (GSH) content has different reaction in different concentration of Ca, Cd. There is discrepancy between different materials. When the rice seedlings were stressed by single cadmium (Cd) for 7days, the increasing cadmium concentration would enhance the content of GSH. The content level of GSH in rice seedlings being stressed for 14 days began to drop after rising first. Its roots and leaves both showed the same trends. The results showed that the synthesis of GSH was severely restrained by cadmium. The longer the stress was, the clearer the final effects were. The calcium of low and moderate concentration (80, 160 mg/L) would improve the level of GSH in rice stressed by cadmium, which slowed the degression speed of GSH and alleviated cadmium (Cd) toxicity to rice seedlings. At the same time, the results indicated that the calcium of low and moderate concentration (80, 160 mg/L) showed better alleviation to the rice seeding of low cadmium concentration (1mg/L) than that in high concentration (1mg/L). But the calcium of high concentration (320 mg/L) would restrict the synthesis of GSH. The amounts of GSH in rice plants treated by calcium and cadmium for 7 days were obviously higher than that treated for 14 days. The effects of calcium on the roots were clearly greater than on the leaves. During the whole process, the content of GSH in Cd-resistant rice species E2B always showed higher than the sensitive species YixiangB. The effects of the stress on YixiangB were more notable than E2B, when treated calcium and cadmium for 7 days. On the contrary, the effect on E2B was more remarkable than the other when treated for 14 days.
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