| In this paper,the soil-cultivated Kandelia candel(L.) Druce seedlings were treated with various contents of Cd and Zn,and the effects on the physiological properties were measured.Hypocotyl germination and growth,chlorophyll content, soluble protein,antioxidase membrane protection system,MDA content,Zn,Cd absorption accumlation character were observed to inquire into the ecophysiological responses of mangrove Kandelia candel(L.) Druce to Zn,Cd phytotoxicity.The results were as follow:1 The shoot of viviparous propagules were promoted at first and then decreased with the increasing Cd contents,while the Zn contents were the same.And the shoot of viviparous propagules were decreased with the increasing Zn contents,while the Cd contents were the same.The survive rates of Kandelia candel(L.) Druce seedlings in difference Zn and Cd concentration were 100%.2 The height growth of stems of Kandelia candel(L.) Druce seedlings was restrained under the Cd treated.But the extent of the restraint became smaller when the seedlings were treated in 100 mg·kg-1 Zn concentration because of the antagonistic effects of Zn and Cd.The height growth of stems of Kandelia candel(L.) Druce seedlings was restrained obviously under high Zn,Cd concentration because of the cooperation of Zn and Cd.3 The area of leaves in different Cd concentration of Kandelia candel(L.) Druce seedlings was promoted step by step under 0 or 500 mg·kg-1 Zn concentration. 100 mg·kg-1 Zn concentration also can promote the area of leaves.4 Under 0 or 100 mg·kg-1 Zn concentration,the roots growth of of Kandelia candel(L.) Druce seedlings was promoted with the increasing Cd contents.Under 100 mg·kg-1 Zn concentration,the number of roots was reduced with the increasing Cd contents.5 The stem biomass of Kandelia candel(L.) Druce seedlings was reduced with the increasing Cd contents.The root biomass and leaf biomass showed significant difference in different time and concentration of Zn and Cd.Effects of different concentration of Zn and Cd on every part biomass were as follows:stem＞root＞leaf.6 The synthesis of chlorophylls of Kandelia candel(L.) Druce seedlings was reduced with the increasing Cd contents under 0 mg·kg-1 Zn concentration.But it was promoted at first and then decreased with the increasing Cd contents under 100 and 500 mg·kg-1 Zn concentration.The synthesis of chlorophylls of Kandelia candel(L.) Druce seedlings was restrained obviously under high Zn,Cd concentration because of the cooperation of Zn and Cd.The ratios of Ch1(a/b) increased at first and then decreased with the increasing Cd contents under 500 mg·kg-1 Zn concentration.The promotion to Chlb was heavier to Chla with low Cd contents.7 Low Cd concentration or low Zn concentration accelerated soluble protein content in roots and leaves of Kandelia candel(L.) Druce seedlings.Under 2.5 mg·kg-1 Cd concentration,the effects of Zn and Cd were antagonistic in root,while Zn cooperation in leaf.8 The transformation trend of SOD activities was similar in roots and leaves with different concentration of Zn and Cd when it was treated 110 days,But the transformation extent of leaves was larger than roots.The activities of SOD were accelerated both in roots and leaves under low Cd concentration.Zn cooperated with Cd,especially 500 mg·kg-1 Zn concentration.9 The transformation trend of POD activities was similar in roots and leaves with different concentration of Zn and Cd when it was treated 80 days,But the transformation extent of leaves was larger than root.The activities of POD were accelerated both in roots and leaves under low Cd concentration.Zn cooperated with Cd.10 The content and transformation extent of MDA in leaves were larger than in roots.The peroxidation of membrane fattiness was pricked up obviously under high Zn,Cd concentration,and MDA contents increased obviously.11 Different organs absorption to Zn and Cd showed significant differences, when the content and transformation extent of every organ ranked as follow: root＞hypocotyle＞stem and leaf.The interactional effects of Zn and Cd made the seedlings absorb more Cd.In 0～100 mg·kg-1 Zn concentration,absorption to Zn was restrained by Cd.But when the Zn concentration increased to 500 mg·kg-1,absorption to Zn in each organ(except for leaf) was accelerated.Absorption to Zn in leaf was restrained with increasing Cd concentration.Enrichment coefficients of Zn and Cd in different organs showed significant differences.The dominatation of root was showed.
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