关键词: 施氮, 冬种绿肥, 土壤活性有机碳, 碳库管理指数, 水稻

Abstract: A pot experiment was conducted to study the cadmium (Cd) tolerance and enrichment of Hemerocallis fulva at different levels of Cd addition. The growth of H. fulva was stimulated when growing at Cd level 0.5 mg·kg^-1, but inhibited when the Cd level was higher than 5 mg·kg^-1. The greening and flowering periods of H. fulva- were prolonged at Cd level less than 5 mg·kg^-1. With the increasing concentration of Cd in the medium, the root activity and leaf chlorophyll and water contents decreased, leaf free proline and soluble sugar contents decreased after an initial increase, and leaf membrane permeability increased gradually. The absorbed Cd in H. fulva was more distributed in root than in shoot. With the increasing concentration of medium Cd, the Cd concentration in shoot and root increased, but the enrichment coefficient and translocation coefficient decreased. The maximum accumulation of Cd in H. fulva was 1.489 mg·plant^-1 when growing at Cd level 20 mg·kg^-1. Based on the growth characteristics and Cd-enrichment capability, H. fulva could be a potential plant used for the remediation of Cd-polluted soil when the soil Cd concentration was less than 1 mg·kg^-1.

Key words: nitrogen application scheme, winter green manure, active organic carbon, carbon pool management index, rice.