施氮对镉胁迫下黑麦草生长和生理特性的影响

以灰漠土为供试土壤，通过盆栽模拟试验研究了施氮对镉胁迫下黑麦草生长和生理特性的影响。结果表明，在土壤镉含量为6mg／kg的水平下施用氮肥后，黑麦草地上部分生物量和平均株高增加显著，施氮200mg（N）／kg（土）和400mg（N）／kg（土）地上生物量分别是空白对照组（CK1）地上生物量的2．96倍和2．29倍。各处理组黑麦草地下部分生物量有所下降，但差异不显著（P〉0．05）。施氮肥可增加土壤镉生物有效态向黑麦草地上部分转移，依次为CK2组的1．20倍、1．39倍、1．43倍和1．92倍。在Cd胁迫下，随施氮量增加，黑麦草细胞脂膜受氧化程度增加，MDA、POD和CAT呈上升趋势，SOD有所下降，其中除POD外，400mg（N）／kg（土）施氮组与对照均呈现极显著差异（P〈0．01）。在土壤镉浓度为6mg／kg条件下，施氮肥（50～400rag（N）／kg（土）]有助于镉向黑麦草体内迁移，黑麦草同时表现出良好的生理防御能力。

Effect of Nitrogen Application on the Growth and Physiological Characteristics of Lolium multiflorum under Cd Stress

This paper studied the effect of nitrogen application on the growth and physiological character- istics of Loliurn multiflorum under Cd stress in grey desert soil by using pot experiment.The results indi- cated that when N application was used,the content of total Cd in soil was 6 mg/kg,the aboveground bio- mass and average plant height of Loliurn multiflorurn increased obviously.And the aboveground biomass in treatments of 200mg（N）/kg（soil） and 400mg（N）/kg（soil） were 2.96 and 2.29 times that of blank control group （CK1） ,respectively. However, the underground biomass of Lolium multiaqorurn decreased, but not significant.Nitrogen application could promote transfer the bio-available state of soil Cd to the above part of cadmium grassland, each group was nearly 1.20,1.39,1.43 and 1.92 times more than CK2 group.Under the Cd stress conditions,the degree of oxidation of cell lipid membranes in Loliurn multiflorum increased with the amount of nitrogen increasing.And MDA,POD and CAT showed a significant increasing tendency,ex- cept for SOD.MDA,CAT and SOD treated with 400 mg（N）/kg（soil） had significant difference compared with the control （P 〈 0.01）.When Cd content was 6 mg/kg, nitriogen application E50-400 mg（N）/kg（soil）] could promote transfer Cd to Lolium rnultiflorum, and Loliurn multiflorurn showed good physiological defensive ability also.