Studies On Mechanism Of Heavy Metals In Water On Ornament Aquatic Plants & Technology Of Tissue Culture

Ornament aquatic plants were one of the important factors in water scenery and wetland scenery designing, and benefit to absorb and accumulate the heavy metals in water,so water quality was improved and maintained effectively. The water was purified and graceful water sight was designed,when the ornament aquatic plants was used in the man-made sewage treatment system. On the basis of investigating the resource and utilization of ornament aquatic plants in Nanjing,Shanghai and Hangzhou,the paper selected eight ornamental aquatic plants to study their heavy metal fastness,such as Acorus calamus ,Canna indica ,Arundo donax L.'Versicolor',Iris Pseudacorus et al. Higher endurance plants and lower endurance plants was further studied on their defense mechanism in heavy metals pollution. The protective enzymes system is the key factor in plant defense responses.The imposition of environmental stress leads to increased production of reactive oxygen species(ROS) in plant cells. The activities of protective enzymes,ROS contents and the relationships among them were studied. A multifactorial appraisal system based on the Analytic Hierarchy Process was developed for eight aquatic plants. Appraisal criteria were judged according to resistance and landscape value of eight plants. Three species were proved better than other species in multifactorial appraisal and tissue culture of three new species was studied.　The results were summarized as follows: Ⅰ. Higher heavy metal (Hg2+,Cd2+)resistance ability were proved in Acorus calamus,Scirpus validus and Canna indica ,and the feeblest resistance ability to Hg2+ was Arundo donax L.'Versicolor'among the eight species. Hg2+ has stronger poison than Cd2+ in these ornament aquatic plants.　Ⅱ. Further studies showed that three species(Acorus calamus , Canna indica , Arundo donax L.'Versicolor') had the same defense mechanism in heavy metals pollution: In the low level of heavy metals pollution , defense responses was acted by ROS and the protective enzymes system worked effectively. When heavy metal pollution concentration enhanced, both heavy metals and ROS injured cell membrane of plants, resulted in the stop of plants growth, even to death.　Ⅲ.The same pathways involved the anti-pollution were also found: Plants can reduce the mercury content and avoid the death of the whole plant by the bondage of heavy metal in the roots, and high enrichment of heavy metal in the roots was taken for a special mechanism.　Ⅳ.The result of multifactorial appraisal of eight plants showed: Canna indica, Acorus calamus and Iris pseudacorus not only beared strong resistance ability , but also took on higher view value, thus they were appraisaled excellent aquatic plants. Based on the appraisal , three new cultivars, such as Acorus calamus 'Versicolor', Iris Pseudacorus 'variegata'and Canna indica 'Versicolor', was choosed, and they were confirmed more sight and as good as original species in resistance. 　Ⅴ.　Tissue culture was studied on the new cultivars, which based on the inconsistency of slow propagation and large market demand, and results showed:　(Ⅰ) In the inducement of adventitious bud of Acorus calamus 'Versicolor',the time of explants made significant effect on bud's differentiation and production effect, and spring was testified best. MS+6-BA5mg/l +NAA0.5mg/l is better to adventitious buds'differentiation and production, and the times of production was about 6 on every bud. Before the period of take root , the tissue culture young plant was cultured in the blank MS medium for one generation, which was proved good. NAA is better to the take root of young plants than IBA, and the best concentration is 0.5mg/l to the rooting of young plants. (Ⅱ)In the bud or flower induction period of Iris Pseudacorus 'variegata', MS+ 6-BA 1mg/l +IBA0.1mg/l was proved best, and the times of production was about 2.85 on every bud. NAA was proved restraining the production of adventitious bud, but in the period of take root of　Iris Pseudacorus 'variegata', it was testified adapt to young plant to take root. It was found that the vitrification of tissue culture young plant was related with the concentration of 6-BA, and took on the positive marked correlation. (Ⅲ)In the culture of shoot tip of Canna generalis cv. striata, the medium that adapt to culture of shoot tip is MS+6-BA2~3mg/l+NAA0.1mg/l. High concentration cytokinin (6-BA) is needed in the culture of clumps of buds and in the induce of flower organ. In the period of peduncular inducement, the medium of MS+6-BA5~10mg/l+ NAA0.5mg/l made good effect and adventitious bud can be induced from peduncle directly. During the subculture of the multiplication of adventitious buds, MS+6-BA8mg/l+NAA0.1mg/l was testified best, and the times of production was about 2.03 on every bud. The rate of differentiation even reach 100. It made no effect to add ZT or KT to medium on the multiplication of adventitious buds. The most fit medium of Canna generalis cv. striata to take root is MS or 1/2MS+NAA0.5mg/l.