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Physiological Response of Polygonum hydropiper,Comnyza canadensis,Polygonum perfoliatum and Phytolacca americana to Manganese Toxicity

2007; Soil and Water Conservation Society; Linguagem: Inglês

1941-3300

Cheng Zheng-xin,

Pesticide and Herbicide Environmental Studies

Four herbaceous plants,Conyza canadensis,Polygonum hydropiper,Polygonum perfoliatum and Phytolacca americana response differently to a wide range of Mn2+ treatments(control,2 000,4 000,8 000,16 000 μmol/L),suggesting that the degree of tolerance or toxicity varies widely in different species.The objectives of this study were first to determine whether there were differences in the physiological responses among the four herbaceous plants based on the malondialdehyde(MDA),membrane permeability(MP),root activity(RA),soluble sugar(SS),chlorophyll and soluble protein contents and second to assess whether there were some correlation between these indexes and Mn overground tissue concentrations.The results indicated that there were some correlation between the physiochemical values and Mn concentrations in plants' overground tissues due to increasing Mn2+ supply.According to the hydroponic culture experiments,16 000 μmol/L Mn2+ significantly(P0.05) promoted the contents of MDA(Phytolacca americana was exceptive),MP and the overground Mn content when compared to the control respectively and these indexes in Polygonum hydropiper increased most while Phytolacca americana rose less.Meanwhile,the soluble sugar(SS),as well as the contents of chlorophyll nearly maintained the same level as each control in Conyza canadensis,Polygonum perfoliatum and Phytolacca americana in comparison with Polygonum hydropiper,whereas,the content of soluble protein didn't show the obvious tendency.The results also implied that Conyza canadensis,Polygonum perfoliatum and Phytolacca americana could enhance the tolerance to Mn stress under high treatments by maintaining lower contents of MDA and MP,higher root activity(RA),steady contents of SS and chlorophyll and the three herbaceous plants,which were satisfied with the standard of Mn phytoaccumulators can be expected during the phytoremediation application.