Research On Physiology And Accumulation Characteristics Of Debregeasia Orientalis C. J. Chen Under Cadmium, Copper And Phosphorus Stress

According to a field survey and a pot experiment, we studied the physiology and accumulation characteristics of Debregeasia orientalis C. J. Chen taken from Baofeng copper mine of Ya’an, Sichuan, China under three single pollution of cadmium, copper and phosphorus. A plot experiment was conducted to study the ability of Debregeasia orientalis for phytoremediation to the Cd, Cu and P polluted soils. The main results were showed as follows:(1) Debregeasia orientalis had showed great ability of accumulation to Cd that when Cd treatments were low the plant was promoted but it was inhibited when Cd treatments were high. The plant height, root length, biomass and photosynthesis and transpiration characteristics of the plant were first enhanced and then reduced with the Cd concentration increased. The plant height, root length and biomass started reduced when Cd treatment was60mg/kg. The photosynthesis and transpiration characteristics were highest at Cd60mg/kg treatment. The POD and CAT activity, GSH and SP content in leaves and roots enhanced firstly and then weakened. The concentration and accumulation of Debregeasia orientalis in shoots and roots were increased when the stress levels of Cd were low and weakened at high Cd levels. Cd concentrations in shoots and roots exceeded100mg/kg when the soil Cd concentration was90-150mg/kg. Shoot and root accumulation of Cd reached maximum of4021.90μg/pot and1757.13μg/pot when the soil Cd concentration was120mg/kg. BCF values of Debregeasia orientalis shoots were more than1.0at the soil Cd concentration of5,30-90mg/kg, the TF exceed1.0when the soil Cd concentration was30、60mg/kg.(2) The growth of Debregeasia orientalis was weakened by Cu significantly, and the accumulation of Cu in the plants and roots promoted under Cu treatments. The root length, plant height, biomass and photosynthesis and transpiration characteristics of Debregeasia orientalis increased firstly and then decreased with the Cu concentration increased. The root length became to decrease at Cu900mg/kg treatment, and the plant height, biomass were inhibited at the soil Cu concentration of600mg/kg, photosynthesis and transpiration characteristics of Debregeasia orientalis started weakened at Cu1200mg/kg. The POD and CAT activity, GSH and SP content in leaves and roots of Debregeasia orientalis enhanced at low Cu treatments then inhibited at high Cu treatments. Debregeasia orientalis had some accumulation ability of Cu, the Cu content of the plant increased steadily at Cu treatments, and Cu concentrations in roots were more than in shoots. Shoot and root accumulation of Cu reached a maximum of396.93μg/potand397.48μg/pot when the soil Cu concentration was600and300mg/kg. The BCF and TF values were all less than1.0.(3) Debregeasia orientalis had strong tolerance of P, and the accumulation ability was fistly increased and then decreased. With increasing rates of added P, the root length, biomass and photosynthesis and transpiration characteristics of Debregeasia orientalis were increased at low P treatments and weakened when P treatments were high. But plant height enhanced at the P treatments. The root length and intercellular CO2concentration weakened with the turning points of P35mg/kg but still more than the control. The highest value of plant height was58.33cm at40mg/kg treatment.The biomass in roots and conductance to H2O in leaves decreased when P concentration was30mg/kg, and the highest biomass in shoots was16.54g at35mg/kg treatment. The values of photosynthetic rate and transpiration rate weakened with the turning points of P25mg/kg. Under P stress, the POD and CAT activity, GSH and SP content in leaves and roots of Debregeasia orientalis were firstly increased and then decreased. Debregeasia orientalis had strong accumulation ability of P. The concentration and accumulation of P in shoots and roots were enhanced at low P levels and decreased at high P levels, the concentration and accumulation in shoots were higher than in roots. The highest concentration in shoots was7.57g/kg, the accumulation with maximum values of103.77g/pot for shoots. The values of BCF of shoots was0.18-0.65and the TF value were all greater than1. Debregeasia orientalis could absorb P that beyond the soil limit, and had some accumulation ability of P.Generally speaking, Debregeasia orientalis had some tolerance and accumulation ability of Cd, Cu and P, being a bioremediation plant which was good at controlling the Cd, Cu and P pollution in soil.