Tolerance And Accumulation Characteristics Of Plumbum In Herbaceous Plants

This research has selected 42 kinds of common herbaceous plants as materials and two hyper-accumulator plants as reference.The tolerance and accumulation characteristics of Plumbum in herbaceous plants were studied with pot experiment method in outdoor.The tolerance and enriched characteristics of herbaceous plants under Pb stress at 500 mg/kg and 2000mg/kg were primarily analyzed.At the same time the mechanism of Pb absorption and transport of herbaceous plants was discussed to evaluat the potential of herbaceous plants in Pb pollution remediation.The main findings are as follows:The herbaceous plants have a higher tolerance to low concentrations of Pb,and the average tolerance coefficient of plant height and root length of the 44 herbaceous plants were 0.91 and 0.85,respectively.The tolerance to high concentrations of Pb was reduced to 0.83 and 0.69,respectively.In terms of biomass,under low concentration stress,there are 28 kinds of reduction,16 kinds of increase,which increase the most significant is the Cosmos-high pole,its root biomass increase reached 75.15%.Under high concentration stress,there were 35 species of reduction,9 species of were increased,and the most significant increased was for the sorghum-F10,and the root biomass increase by 36.57%.Different herbaceous plants are quite different in absorption capacity of Pb,at the low concentration of Pb treatment,the highest content of Pb in the ground is Alkali Mao grass reached to 994.11 mg/kg,which is 2.15 times to the Vetiver,1.30 times that of Beggars-ticks.At the high concentration of Pb treatment,the highest content of Pb in the ground is Watercress,which is 2.02 times to the Vetiver,1.27 times that of Beggars-ticks.This shows that some plants have a high absorption capacity.The content of Pb in the shoots above 1000mg/kg at the concentration of 2000mg/kg,include Watercress,Alkali Mao grass,Elymus,Hollyhock,Bluegrass-Rhapsody,which has the potential characteristics of hyper-accumulators.Among the 44 herbaceous plants,in the low Pb treatment,the Blugrass-Excellent and Alkali Mao grass,which both the transport coefficient and the above-ground enrichment coefficient are greater than 1.In the high Pb treatment,both the transport coefficient and the above-ground enrichment coefficient are greater than 0.5,include Elymus,Alkali Mao grass,Beggars-ticks,Watercress,Hollyhock.