| From 2007 to 2010, Yellow Sea of China had experienced the large scale green-tide consecutively. The green-tide had damaged the offshore economy and enviroment. The dominating blooming alga was Enteromorpha prolifera (Muell.) J. Agardh (Chlorophyta, Ulvophyceae). There are two stages in the life-history of E. prolifera: visible thalli and microscopic propagules. It is necessary to do some work about the algae's physiological ecology. Preliminary work had been down to explain how the temperature, salinity and other enviromental factors effect the two stages.The study of the effects about temperature and salinity on the growth and reproduction of E. prolifera shows: The optimum temperature scale is 20℃～23℃, and optimum salinity range is 26～32. In the higher salinity (20～32), the maximum SGR appeared at 20℃, while at the salinity of 14, the maximum specific growth rate(SGR) appeared in the range of 23℃～26℃. The highest SGR among all treatments was 37.80% per day at 20℃, and salinity 26. The groups with higher SGR(≥14℃)during the vegetative stage went to the reproductive stage earlier. And then, the SGR of those groups decreased dramatically. Within the vegetative growth period, the thallus developed strongly and branched abundantly and proliferously. After that, most of the thallus performed the productive growth. Initially the color of the thallus changed from dark green to light yellow, while sporangia (gametangia) were formed. After spores (mostly) or gametes were released into the culture water and the color of thallus changed to white at the same time. Several days later, the reproductive cells germinated to numerous young offspring. The process of the color-changing of thallus can be used as the symbol for its different growth stages. The Enteromorphra juvenile contributed to the biomass of the population.In order to know more about the fundamental mechanism of the algae's growth, the effects of salinity(8～32), temperature(1℃～40℃) on photosynthetic oxygen production rate of E.prolifera were studied. The results showed that, E.prolifera is typical intertidal alga, because of high light saturation intensity(Isat, 567μE?m-2?s-1, mean), high light compensation intensity(Ic, 62μE?m-2?s-1,mean). The oxygen prodution rate was highest at salinity scale of 26～32, to the contrary, lower salinity restrained the photosyntetic rate. It also performed high optimum temperature of photosynthesis (20℃～27℃). At 23℃, the maximum net oxygen production rate(Pnmax) was highest(299.25μmolO2?h-1?gwt-1), and the maximum of the light utilization efficiency(LUE) was also highest. However, lower temperature (1℃～14℃) or higher temperature (27℃～40℃) limited the photosynthsis.The microscopic propagules include spores, gemetes, zygotes and microscopic plantlets, etc. All quantitative data in this paper were about the quadri-zoospores obtained from E.prolifera's thallus. We studied how the factors like time course, temperature and water motion effect the zoospore adhesion procedure. The time course for two different concentration zoospores adhesion experiments was performed. The results showed that the adhesion rate was concentration dependent. After adhesion in the darkness for 24 hours, the higher concentration group's adhesion rate was 54.1%, while that of lower concentration was 48.4%. The rate of zoospore adhesion was greatest during the first 4 hours and appeared to level off after that. Zoospore adhesion was temperature dependent, with an optimum of 25℃.In the initial 4 hours(the key period of adhesion procedure), slight water motion (flow velocity≤17.6cm·s-1) would improve adhesion rate. However, at the time course of 12 hour, the adhesion rate in the stationary water was highest. Additionally, fierce water motion (flow velocity≥35.2 cm·s-1) restrained the zoospore adhesion throughout.Frequently, the ecology and the ecophysiology of adult macroalgae have been insufficient to explain their seasonal abundances. Thus, it is essential to understand the factors that regulate the germination and growth of spores of E.prolifera. In the present work, we designed orthogonal test to assess the effects of temperature, salinity and light on the germination and growth of E.prolifera spores. The results highlighted the fact that, the biomass at 15℃was only 8% of that at 30℃. The temperature above 15℃was essential for the germination and growth of spores. 5℃and below inhibited the growth of young plantlets. Higher salinity of 20 or 35 promoted the growth, while 5 restrained the biomass of offsprings. Additionally, Growth of the spores was significantly decreased at the irradiance of 35μE?m-2?s-1, while the irradiance of 60μE?m-2?s-1,120μE?m-2?s-1 clearly promoted the spores growth. In our study, the test group of 30℃,33,120μE·m-2·s-1 is the optimum condition for the germination and growth of spores. The present results contribute to increase the understanding about the factors that control macroalgal growth at its early phases of development.
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