Effects Of EDDS And Plant Growth Regulator On Enhancing Phytoextraction Of Cd By Galinsoga Parviflora

Galinsoga parviflora is a Cd-hyperaccumulator discovered by our research group previously. Similar to most hyperaccumulators, the Cd recovering efficiency of Galinsoga parviflora is recovering Cd is restricted by low biomass and bioavailability of heavy metals in soils.Using clalating agents and plant growth regulators could enhance the bioaccumulation ability of heavy metals, then enhancing phytoremediation efficiency.In this study, EDDS, GA3,2,4-EBL were used to processes the plant tests for research the characteristics of physiological,biochemical characteristics and Cd-hyperaccumulator during the development of Galinsoga parviflora under different processing conditions. The results showed:(1) All treatments of EDDS were significantly increase the activity of POD and APX in the leaf of Galinsoga parviflora(p<0.05), and showe a trend of rising with the growing concentration of EDDS. When the concentration of Cd is 50 mg·kg-1, adding 2mmol·kg-1 of EDDS could make the activity of POD and APX of Galinsoga parviflora respectively increase by 29.80%(p<0.05)and 31.16%(p<0.05), but the activity of SOD and CAT was 15.49%(p<0.05)and 28.65%(p<0.05)lower than the control group.(2) The concentration of EDDS in 2 mmol·kg-1 found best result to promote of the Cd-hyperaccumulator of Galinsoga parviflora.In different concentrations (5,25,50mg·kg-1) of cadmium, adding 2 mmol·kg-1 EDDS could make the Cd content and accumulation in the aerial part of Galinsoga parviflora increase from 23.48% to 33.86%(p<0.05) and from 20.98% to 30.70% (p<0.05)compared with the control group.(3) Spraying GA3 and 2,4-EBL could promote the growth of Galinsoga parviflora under cadmium stress. With the increase of concentration of plant growth regulators, the biomass in the aerial part of Galinsoga parviflora showed a trend of increasing firstly and then a decreasing trend, and are larger than the control group. Spraying 10-5mol·L-1 GA3 and 10-8mol·L-2,4-EBL made the organisms in the aerial part of Galinsoga parviflora respectively increase from 22.23% to 27.17% (P<0.05)and from 14.35% to 20.41%(p<0.05)compared with the control group.(4) 10-6mol-L’1 GA3 improves the cadmium accumulation in the aerial part of Galinsoga parviflora, which increases from 22.23% to 25.94 %(p<0.05)compared with that of the control group. Spraying 2,4-EBL could reduce the cadmium accumulation in the aerial part of Galinsoga parviflora.(5) Integration of plant growth regulators with a suitable concentration and chelating agents not only improves the biomass of Galinsoga parviflora under Cd stress, but also promotes the absorption and accumulation of Galinsoga parviflora on Cd.10-6mol·L-1 GA3+EDDS makes the organisms in the aerial part of Galinsoga parviflora respectively increase from 10.05% to 13.39% (p<0.05), the cadmium accumulation in the root part and aerial part of Galinsoga parviflora increase from 29.10% to 45.16%(p<0.05)and from 51.89% to 62.88%(p<0.05)compared with the control group, which also makes the metal extraction rate of Galinsoga parviflora increase from 52.44% to 65.38%(p<0.05).