两种油菜不同铅富集能力差异机理

通过水培试验和大田试验研究了秦油1号（QY-1）和三月黄（SYH）2种油菜对Pb的吸收富集能力，并从叶片的亚细胞结构和抗氧化酶活性等角度探究二者对Pb的耐性和解毒机制.结果表明，在水培条件下，2种油菜的生长均未受到明显的抑制，随着Pb胁迫的增加，油菜吸收的Pb更倾向于分配在根部，减弱向地上部的转运.同时，在高Pb处理浓度（20mg/L）下，SYH的地上部和根部的Pb含量分别比QY-1提高了17.03%和77.07%.油菜叶片中Pb亚细胞区隔化研究结果表明，将Pb区隔在生物解毒组分（金属富集颗粒组分和热稳定蛋白组分）中是油菜富集Pb的重要耐性机制，其中SYH在该组分中Pb的分布显著高于QY-1.此外，抗氧化系统是这2种油菜应对Pb胁迫的重要解毒机制，Pb胁迫下SYH体内过氧化物酶和过氧化氢酶活性显著高于QY-1，可更有效地应对Pb胁迫对其的毒害效应.大田试验表明，田间条件下2种油菜吸收的Pb更倾向于转运到地上，且SYH的富集系数、地上部和根部Pb含量均显著高于QY-1.综上，SYH具有更高的Pb富集能力，具有修复中轻度Pb污染土壤的应用潜力.

Mechanism of the two cultivars of rapes with different Pb enrichment ability

Hydroponic and field experiments were conducted to explore the Pb absorption and accumulation ability of two cultivars of rapes, QinYou No.1 (QY-1) and SanYueHuang (SYH). The subcellular compartmentalization of Pb and antioxidant enzyme activities were determined to clarify the differences in Pb tolerance and detoxification mechanisms between the two cultivars of rapes. The results showed that SYH was higher than QY-1 in the growth under different Pb stress concentrations. Both cultivars of rapes tend to distribute Pb in root rather than shoot under hydroponic conditions. Meanwhile, under 20mg/L Pb stress, Pb concentrations in root and shoot of SYH were significantly higher than QY-1by 17.03% and 77.07%, respectively. Moreover, the results of Pb subcellular compartmentalization in leaves of the two cultivars of rapes showed that the enrichment of Pb in biological detoxified metal factions (heat stable protein and metal-rich granule) played an important role in the detoxification of the two cultivars of rapes, which was significantly higher in SYH than QY-1. In addition, antioxidant system also played an important role in the detoxification of Pb. Peroxidase activity and catalase activity in leave of SYH were significantly higher than QY-1, which implied that SYH possess advantages to cope with Pb stresses over QY-1. In the field experiment, Pb could be translocated to aboveground part more effectively compared with hydroponic conditions. Moreover, bioconcentration factor (BCF) and Pb concentrations in both shoot and root of SYH were significantly higher than those of QY-1. Therefore, SYH has higher Pb accumulation ability and thus more suitable for the remediation of mildly and moderately Pb contaminated farmland soils.