| The pollution of heavy mental in mangrove marsh is ag gravated and there are advices of making use of mangrove in sewage treatment at present. There are 4 treatments of Cd including control(0mg/L),low Cd (0．5 mg/L),medium middle Cd (1mg/L),high Cd (2mg/L) .The 4 N treatments comprises control(0 mg/L),low N (0．5 mg/L),middle N (1mg/L),high N (2mg/L) . In this paper, mangrove species Aegiceras cornicula Turn hypocotyls were cultivated in sand and treated with 10‰water for 90 days in a greenhouse under the interactive treatment of N and Cd. The influence of different concentrations of Cd and N interaction on Aegiceras cornicula Tum including the biomass, N content and Cd content of different parts, chlorophyll content and antioxidase membrane protection system were observed after 90 days. The results showed:1．The biomass of the roots, stems and leaves varied with the Cd concentrations in different N group. In most of the treatments, the biomass reduced when the Cd concentration increased. The biomass of roots, stems and leaves were promoted when the N concentration increased under the same Cd treatment. It indicated that N accelerated the growth of the Aegiceras cornicula Tum and the biomass of roots, stems and roots were promoted follow the increasing of N. N allayed the intimidation of Cd on Aegiceras cornicula Tum.2．The N content of the roots, stems and leaves varied with the Cd concentrations in the experiment. The N content of leaves was higher than stems and roots. When the Cd concentration increased the N content of different parts of Aegiceras cornicula Tum reduced under the same N concentration. But when the N concentration was enhanced under the same Cd concentrations the N content of different parts were promoted. The N content of different parts showed a climb when the N concentration increased in the high Cd treatment (2mg/L) .It indicated that N allayed the intimidation of Cd on Aegiceras cornicula Tum and it have endurance on Cd.3．The experiment showed that the Cd content of roots was higher than stems and leaves. The Cd content of different parts showed a climb under the same Cd treatment when the N concentration increased. The Cd content of different parts were also promoted when the Cd concentration increased under the same N treatment. It indicated that N was a stimulative of Cd accumulation. The Cd accumulation of different parts of Aegiceras cornicula Tum dropped when the Cd concentration increased under the same N treatment. It indicated that the transfer of Aegiceras cornicula Tum was restrained despite the Cd concentration increased in culture medium. 4．The contents of chlorophyll a, chlorophyll b and total chlorophyll were enhanced when the N level increased in different Cd groups except high Cd (2．0mg/L)group, in high Cd group these indexes reached the max in the low N (20mg/L)treatment, Chlorophyll a/chlorophyll b dropped when the N concentration increased. The contents of chlorophyll a, chlorophyll b and total chlorophyll showed a decline when the Cd concentration increased under the same Cd treatment. But the trend was not consistent in statistical analyse.5．The experiment show that SOD total activity of leaves has the similar trend under the same N treatment. The SOD total activity of leaves under low Cd (0．5 mg/L) and middle Cd (1 mg/L) were higher than control under the same N treatment. And the SOD total activity dropped under high Cd (2mg/L) treatment. The SOD total activity was promoted with the increase of N concentration in control group and high Cd group. When N concentration increased the SOD total activity was reduced in low Cd group. There was no significant difference between treatments in middle Cd (1 mg/L) group.6．POD total activity obviously increased in low Cd (0．5 mg/L) and middle Cd (1 mg/L) treatment. The trend of POD activity in high Cd (2mg/L) was not consistent with control. The POD total activity was lower than the control in the control (0 mg/L) group. There was no significant difference between different treatments in low N (20 mg/L)group. But the POD total activity significantly higher than control in middle N and high N treatment. The POD total activity was lessened in control group, low Cd group and middle Cd (1．0ppm/L)group when the N concentration increased. In high Cd group there was a reverse trend.7．Under the same Cd treatment the MDA content of leaves reduced when N concentration increased except the control (0 mg/L)group. There was no significant difference between treatments in control group(Cd-0) This phenomena show that N alleviated the harm to the Aegiceras cornicula Tum. The MDA content of leaves increased when the Cd concentration increased in different N groups. It indicated that the harm to Aegiceras cornicula Tum of Cd was significant.
|
PDF Full Text Request