Effects Of Cd、Pb And Their Compound Pollution On The Growth And Nutritional Quality Of Water Fennel And The Enrichment Characteristics

In this paper, we cultivated Tongcheng cress in the co-contaminated fields applied with 0, 1.0, 2.0, 3.0 mg·kg-1 Cd and 0, 400, 800 mg·kg-1 Pb, and studied different organs of water fennel on the absorption, distribution and accumulation of Cd and Pb to reveal the relationship between each other in various organs, and studied the index of absorption, distribution of Cd and Pb, morphological characters,physiological and biochemical, nutrient quality of water fennel. The main results are as follows:(1)Under the individual pollution of Cd, the plant fresh weight, mean root length and plant height increased at first and then descended with the Cd concentration increasing, and they were a bit better than the control group at low concentration. The root number was always decreasing. But the plant fresh weight, mean root length, root number and plant height all descended with increasing of the two elements under the individual Pb pollution and compound pollution.(2)The chlorophyll content, chlorophyll a and chlorophyll a/b value all declined with increasing external Cd concentration under single Cd pollution and ascended at low lever of Pb but descended at high lever of Pb under single Pb pollution. At the same time, Cd had synergistic effect on chlorophyll b while Pb had antagonistic effect on chlorophyll b content both in the individual pollution. The Cd and Pb combined pollution always had a greater impact on all the chlorophyll content than the individual pollution condition, and they all decreased as the pollution concentration increasing except chlorophyll a/b value.(3)The content of vitamin C, soluble protein and soluble sugar of petioles were effected by Cd, Pb and interaction of Pb and Cd significantly. Statistical population decreases with the increase of concentration of pollution. The content of vitamin C and soluble protein were strongly influenced by Pb concentration, while soluble sugar content was mainly affected by Cd concentration. Among them, the vitamin C content under the influence of compound pollution was most obvious which were significantly stronger than the single pollution.(4)The results showed that at the same level of treatment, the sequense of Cd content in different organs was: roots>petioles >leaves, while the Pb content in roots was much greater than that in petioles and leaves. The absorption of Cd and Pb to different organs of water fennel showed an increasing trend with the increase of Cdand Pb concentration, and the interaction effect of Cd and Pd on absorption also reached an extremely significant level. Moreover, Pb had synergistic effect on Cd content all the time while Cd had antagonistic effect on Pb content in the root, but had different synergistic on Pb content in the petiole and leaf. The heavy metal enrichment coefficient to underground part of plant was bigger than that of overground part.