煤基腐殖酸对外源砷胁迫下玉米生长及生理性状的影响

Effects of coal-based humic acids on growth and some physiological characters of maize stressed by exogenous arsenic

为了筛选用于砷污染土壤治理的煤基腐殖酸,采用盆栽实验研究了施用不同种类和浓度的煤基腐殖酸及EDTA对外源砷胁迫下玉米株高、株鲜重、株干重、根干重、砷积累量、叶片抗氧化酶(POD,SOD和CAT)活性和脯氨酸含量的影响。结果表明,11种供试煤基腐殖酸均促进了玉米生长,提高了叶片POD、SOD和CAT活性。其中6和10号腐殖酸可降低土壤砷活性和显著抑制玉米吸收和积累砷,而8和9号腐殖酸增加了土壤活性砷和显著促进了玉米对砷的吸收和累积,且不同程度地强于EDTA。除8和9号外,其余腐殖酸均可明显降低玉米叶片脯氨酸的含量。EDTA可显著促进玉米吸收和积累砷,且加剧了砷对玉米的危害。因此,8和9号供试煤基腐殖酸可以替代EDTA活化土壤砷,与植物配合以提高砷污染土壤的植物修复速度和效果,而6和10号供试煤基腐殖酸则可用于土壤砷钝化剂,以保证作物产品的安全。

In order to select coal-based humic acids for strengthening the phytoremediation of As-polluted soil, a pot experiment was conducted to study the effects of different kinds and concentrations of coal based hu- mic acids and EDTA on the plant height, shoot fresh weight, shoot dry weight, root dry weight, arsenic accumu- lation, antioxidant enzymes （POD, SOD and CAT） activities, proline contents of maize （Zea Mays） stressed by exogenous arsenic. The results showed that 11 kinds of experimental coal-based humic acids all promoted the growth of maize and increased the POD, SOD, and CAT activities in leaves at various degrees. The No. 6 and I0 humic acids decreased the As activity of soil and significantly inhibited the absorption and accumulation of maize to arsenic, but the No. 8 and 9 humic acids increased the As activity of soil and significantly promoted the absorption and accumulation of maize to arsenic and stronger than EDTA at various degrees. All experimental hu- nic acids significantly reduced the contents of proline in leaves of maize except No. 8 and 9 hunic acids. EDTA significantly increased the absorption and accumulation of maize to arsenic and aggravated the damage of arsenic stress to maize. Therefore, the No. 8 and 9 coal-based humic acids may replace EDTA as activators for increasing the activity of arsenic in soils and increase the speed and effect of phytoremediation of As-contaminated soils co- ordinating with plants, while the No. 6 and 10 coal-based humic acids may be used as inhibitors of soil arsenic for ensuring the safety of crop products.