Study Of Reproduction Physiology And Tissue Culture Of Submerged Macrophytes

Restoration of aquatic ecosystem in eutrophic lakes relys on restoration of submerged vegetation. Vegetative and sexual reproduction under eutrophic conditions may play important role in the establishment of submerged plant community.Restoration of submerged vegetation requires large amount of macrophyte biomass that is obtained from other water bodies. This method may cause damage of the source ecosystem, and may encounter insufficient supply of macrophyte. Micropropagation of macrophyte is a promising technique to provide large amount of seedlings in a short time at all seasons and with no harm to the natural macrophyte community. In this paper, micropropagation of Potamogeton crispus L. is established through stem organogenesis. Internode segments were surface-sterilized with 5%H₂O₂ for 15min and then with 6% PPM (plant preservative mixture) for 15 min. Explants were cultivated in MS medium supplemented with 6-BA:IBA=1.0-3.0:0.5 mg·L^-1, and solidified with 0.8% agar. Buds were regenerated after incubation. New buds were transferred into proliferation medium After 1-2 weeks cultivation the sprouts were transferred into MS medium containing IBA:6-BA=1.0-3.0:0.5 mg·L^-1 for root induction. After roots regenerated, the seedlings were transferred out for planting after a short acclimation period.Submerged macrophytes P. crispus L., Potamogeton pectinatus, Najas marina, Myriophyllum spicatum, Vallisneria natans and Potamogeton malainus are widely distributed and abundant in Chinese lakes. In this study the effects of anoxia and other ecological factors, e.g. nutrients, light intensity, temperature, pH, pre-cooling treatment, on the germination of turions of P. crispus and seeds of P. pectinatus, N. marina, M. spicatum, V. natans and P. malainu were investigated.The results indicated that dissolved oxygen affected the germination rate and the number of bud per turion significantly, and anaerobic conditions enhanced germination of turion of P. crispus L. and number of bud per turion; however, temperature and the concentration of nitrogen and phosphorus had no effect on the germination. Dissolve oxygen and temperature also affected the growth of shoots of P. crispus L. in tow weeks after germination, while no effect was found related to the concentration of nitrogen and phosphorus. Under the condition of high dissolved oxygen, the shoots grew normally at...