不同品种菜心对镉抗性的研究

以对镉（Cd)抗性不同的两个菜心品种特青60天和迟心2号为试验材料,用盆栽土培试验的方法研究了在不同浓度Cd处理下（0mg/kg,1.0mg/kg,3.0mg/kg,10.0mg/kg)Cd在菜心体内及迁移的差异，并探讨了造成差异的机理。研究结果表明：Cd处理下，特有60天茎叶中积累的Cd比迟心2号的少，在高Cd浓度（10.0mg/kg)下，与对照相比，特青60天的干重明显增加，而迟心2号的干重则显著降低。进一步分析研究发现，在相同的Cd上，特青60天中Cd的迁移率较小，特别是在30mg/kg Cd处理下比迟心2号的低5．62％；根系细胞壁中的Cd所占的比例比迟心2号的高；特青60天根系中全硫（S）的含量比迟心2号的高，而且随着Cd处理浓度的增加，全S含量提高，但迟心2号中S含量的变化趋势与之不同；持青60天根系汁液的pH值比迟心2号的高，且汁液中Cd的含量比迟心2号的低；相关分析的结果显示；根系汁液中的Cd含量与茎叶汁液中Cd的含量呈显著的正相关关系。以上的结果可能造成了特青60天中Cd在根系内的活性和迁移能力较低，减少了Cd由根系向茎叶的迁移，从而使特青60天对Cd的抗性高于迟心2号。

Studies on the Resistance to Cadmium in Different Cultivars of Brassica parachinensis

The differences of translocation and accumulation of cadmium (Cd) in Brassica parachinensis of different Cd-resistant cultivars,Chixin-2 and Teqing-60,and their mechanisms were investigated with pot experiment in greenhouse under the different Cd treatment (0mg/kg,1.0mg/kg,3.0mg/kg,10.0mg/kg).The results showed that,at the same Cd treatment,the resistant cultivar Teqing-60 accumulated fewer Cd in shoots than Chixin-2.Under the higher Cd concentration (10.0mg/kg),dried weight of Teqing-60 was significantly increased,while that of Chixin-2 was remarkably decreased,compared to the control.In Chixin-2,dried weight of shoot and root were decreased by 52.54% and 68.85%,respectively.Furthermore,the translocation rate of Cd from root to shoots was lower in Teqing-60,especially under the 3.0mg/kg Cd treatment,lower by 5.62%,than that in Chixin-2.But the proportion of Cd in root cell wall in Teqing-60 was higher than that in Chixin-2.The total sulfur content in root were higher.Moreover,total sulfur in Teqing-60 were raised by 25.78% to 43.50%,but that in Chixin-2 were reduced by 1.0% to 32.60%,after adding Cd to soil.And pH value of root sap in Teqing-60 were higher than that in Chixin-2,higher by 1.02 pH unit,specially under 3.0mg/kg Cd treatment.Cd content in root sap was lower for Teqing-60,accordingly,the activity and translocation ability of Cd in Teqing-60 were lower than that in Chixin-2.And the Cd content in root sap were positively correlated with that in shoot (R 2=0.8151,n=8).The above results might be the reasons why the resistance of Teqing-60 to cadmium was higher than that of Chixin-2.