Studies On The Accumulation, Mechanism And Influencing Factors Of Cadmium Absorption Of Four Species Of Iris L.

The mechanisms and influencing factors of Cd absorption, accumulation and tolerance of four species of Iris L., Iris pseudacaorus,I. tectorum,I. halophila and I. lactea var. chinensis were studied by hydroponic culture with different contentrations of Cd supplied with CdCl₂·2.5H₂O. The main results as follows:1 The Cd tolerance and accumulation of four species of Iris L.Effects of cadmium on the tolerance and accumulation of I. pseudacorus, I. tectorum, I. halophila and I. lactea var. chinensis were studied by hydroponic culture with different concentrations of Cd. The result indicated that the contents of Cd in the leaves of four species exceeded 100ug/g, the standard of Cd hyperaccumulator, and the specy of the highest Cd content was I. lactea var. chinensis, reached 170.97ug g^-1 and the lowest, I. tectorum, 120.65ug g^-1 at 10 mg L^-1 Cd treatment. And the biomasses of four Iris species were not significantly different compared with the control. The content of Cd in the leaves of four species were increased as the Cd concentration increased and the content of Cd in the leaves of I. lactea var. chinensis, I. tectorum, I. halophila and I. pseudacorus were 528.84, 471.73, 347.11 and 299.8ug g^-1 respectively at 80 mg L^-1Cd treatment and the dry weight (DW) of leaves of these species were dropped 28.9%, 56.7%, 31.9% and 36.6% respectively. The leaf dry weight(DW) of I. lactea var. chinensis and I. halophila were no-significant difference compared to the control at 80 mg L^-1Cd treatment(P>0.05). The ratio of Cd contents in the leaves and roots (L/R) of I. lactea var.chinensis was highest reached 0.85. All the results showed that I. lactea var. chinensis was much better in Cd absorption and translocation than other three species.2 The effects of different Cd concentrations on physiological and biochemistry properties of Iris lactea var. chinensis and I. tectorumThe results in the research showed that all the Cd treatments were poisonous to I.