关键词: 巨桉, 铅胁迫, 生长特性, 土壤类型, 富集特性

Abstract: To explore the effect of Pb stress on physiological characteristics and Pb accumulation of eucalypt (Eucalyptus grandis) s eedlings in three soil types (calcium purple soil, acid purple soil, and alluvial soil), a controlled pot-experiment cultivated with one-year old eucalypt seedlings, treated with four Pb concentrations (CK: 0 mg·kg^-1; T1: 200 mg·kg^-1; T2: 450 mg·kg^-1; T3: 2 000 mg·kg^-1), was conducted. The results showed that low levels of Pb stress promoted the growth of eucalypt seedlings and this promotion was the best in the calcium purple soil, but the high levels of Pb stress severely inhibited the growth. The biomass of each organ and total biomass increased first and then decreased with the increase of Pb concentration, and they were both maximum under T1 and minimum under T3. The Pb content of each organ showed a significant increased tendency with the increase of Pb concentration in three soil types. The Pb content of aboveground part was far less than that of belowground part, and the fine root had the largest content. The uptake of Pb in the calcium purple soil was less than other two soils. Eucalypt seedlings all showed certain absorption and bioaccumulation characteristic of Pb at different Pb levels, and the eucalypt seedlings grown in the acid purple soil had higher bioaccumulation coefficient and tolerance index relative to other soil types. This result suggested that eucalypt had a better repair effect in the Pb polluted acid soil.

Key words: Eucalyptus grandis, Pb stress, growth characteristic, soil types, bioaccumulation characteristic