改良剂对镉污染土壤上小白菜镉积累转运及生理特性的影响

Effects of amendments on cadmium accumulation and transport and the physiological characteristics of pakchoi cabbage in cadmium-contaminated soil

为了缓解土壤镉污染对小白菜的胁迫,以园林绿色废弃物堆肥、生物炭和腐植酸为复合改良剂,研究了不同改良剂添加量对土壤理化性状、小白菜生物量、镉积累转运、叶片色素含量和生理特性的影响。结果表明:随着改良剂施用量的增加,土壤pH值、EC值和有机质含量增加,土壤有效态镉含量降低。施用改良剂后,小白菜根和叶的生物量分别提高了46%~53%和30%~64%。改良剂添加显著降低了小白菜根和叶中镉含量,同时根和叶的富集系数(BAF)分别降低了12%~30%和34%~49%,转运系数(TF)显著低于对照,但仍大于1。改良剂施用显著提高了小白菜叶片中的叶绿素a、叶绿素(a+b)和类胡萝卜素含量。小白菜的丙二醛(MDA)含量、超氧化物歧化酶(SOD)和过氧化物酶(POD)活性、脯氨酸含量等抗逆性指标明显降低。研究表明,改良剂施用改善土壤理化性状,提高小白菜生物量和叶片色素含量,降低抗逆性指标,同时显著降低小白菜对镉的积累转运。

In order to alleviate the stress of soil cadmium pollution on pakchoi cabbage.In this study,green waste compost,biochar,and humic acid were used as composite amendments to examine the effects of different levels of addition on soil physiochemical properties and the biomass,cadmium accumulation and transportation,leaf pigment content,and physiological characteristics of pakchoi cabbage.The results showed that with an increase in the amounts of amendments applied,there were increases in soil pH and electrical conductivity values and organic matter content,whereas available cadmium content decreased.In response to amendment,there were also increases in the biomass of pakchoi cabbage roots and leaves of 46%~53%and 30%~64% respectively.Furthermore,the bioaccumulation factors of roots and leaves decreased by 12%~30% and 34%~49%,respectively,whereas although the translocation factor was significantly lower than that of the control,it was still greater than 1.In addition,the contents of chlorophyll a,total chlorophyll(a+b),and carotenoids in the leaves of pakchoi cabbage were significantly increased by the application of amendments.There were also significant reductions in the contents of malondialdehyde and proline and the activities of superoxide dismutase and peroxidase in pakchoi cabbage.In general,the application of amendments improved soil physicochemical properties,increased the biomass and leaf pigment contents of pakchoi,reduced indices of stress resistance,and significantly reduced the accumulation and transportation of cadmium in pakchoi cabbage.