The Physiological Ecology And Reproduction Biology Of Sargassum Thunbergii

Sargassum thunbergii is one kind of warm temperature marine brown alga in the west of North Pacific Ocean, also distributed widely in China seacoast. In China, the application of S. thunbergii had a longtime history, especially in food and medicine fields. Recent years, the application fields developed further, especially in the field of aquaculture feedstuff, as one kind of good food of sea cucumber and abalone, the demands of S. thunbergii were increased quickly. While the supply of S. thunbergii mostly relied on the wild algae, the culture of S. thunbergii was little. With the gathered amounts increased, the wild resources of S. thunbergii were destroyed seriously, which made the contradiction of supply and demand increased further, and the ecological environments were also destroyed. Based on these reasons, people began to pay more attentions to the study of S. thunbergii recently.In the paper, S. thunbergii were studied in 4 aspects: the ecology research in the nature state and the rules of growth and development, the process of sexual reproduction of S. thunbergii and its application of seedling breeding, inorganic nutrition absorption experiment of S. thunbergii and the relations of S. thunbergii and bacteria were also studied.In the ecology research of S. thunbergii, we studied the growth and development states of S. thunbergii in Qingdao Huiquan Cape for about 1 year, the knowledge about growth and development of S. thunbergii in the whole year were gained. S. thunbergii could grow in the whole year, and the physiological characteristics were diverse in different seasons. The rhizoids were important to the population's development, the regeneration seedlings by rhizoids were the population's principal part. As though the success ratios of the sexual reproduction and seedling's survival rate were low, the seedlings that produced by sexual reproduction still occupied a certain proportion. In the experiment of sexual reproduction and seedling breeding of S. thunbergii, the biological characteristic of mature algae, the development of receptacle and the process of sexual reproduction were observed, and the seedling breeding were also carried.In the inorganic nutrition absorption experiment of S. thunbergii, the inorganic nitrogen and inorganic phosphorus were both absorbed well, 1kg algae could absorbed 75.1mg inorganic nitrogen and 36.2mg inorganic phosphorus from seawater every day, and the absorption proportion of nitrogen and phosphorus in amount of substance approached to 5:1.In the study of relations of S. thunbergii and bacteria, the results showed that the inhibition of S. thunbergi to vibrio and the total bacteria were both existed. The inhibition effects were boosted after the algae were cultured in room for a long time, showed that the growth condition influenced the bacteriostasis abilities of S. thunbergi. Moreover, the bacteriostasis abilities of S. thunbergi could be applied to purify the water quality and control the diseases of the marine aqucultured animals.Based on our studies, the following results could be gained: It was feasible in theories that nurturing S. thunbergii seedlings utilizing sexual reproduction process, and the key technique which should be resolved in the next step is that reducing the loss of seedlings and increasing the survival rates. The regeneration seedlings by rhizoids were the population's principal part, and the common harvest manner that gathering with rhizoids made the wild resources damaged severely. It was proposed that wild S. thunbergii should be gathered in the end of July or early August, when the algal biomass closed to the maximum and the sexual reproductive were also completed, using the method of cutting the branches at the same time reserving rhizoids and small branches. It was also proposed that further exploiting the de-eutrophication abilities of S. thunbergii and purifying the culture environment water, the inhibition abilities that S. thunbergii to vibrio and the total bacteria, to establish the farming mode of sea cucumber, abalone and S. thunbergii cultured together well, in this mode, it could be achived that ecological complementary, environment-friendly and the quantities and qualities of aquatic products improved also.