Growth and Fv/Fm in embryos of Hizikia fusiformis （Harvey） Okamura （Sargassaceae,Phaeophyta） cultured under different temperature and irradiance conditions

摘要

Understanding the embryo physiology of Hizikia fusiformis(Harvey) Okamura will promote the development of artificial seedlings. In this study, H. fusiformis embryos were cultured under different environmental conditions, including different temperatures(15°C, 20°C, and 25°C), sunlight intensities(100%, 50%, and 25% of full solar radiation) and types of UVR(UV-A and UV-B). Then, we determined the lengths, maximal quantum yields( F_v/F_m), and survival rates of the embryos. The results showed that the embryos had the highest lengths, F_v/F_m values and survival percentages when cultured under a temperature of 20°C and 25% sunlight intensity. The full level of solar radiation severely reduced the growth and survival ratios of the embryos. Hizikia embryos recovered within 2 h from the damage caused by short-term(30 min) high radiation(about 70% of full solar radiation) and UVR exposure. However, the viabilities of the embryos were significantly decreased after 4 h exposure to UVR. According to these results, we propose that culture conditions with indoor natural light and room temperature would be favorable for the growth, development and physiology of H izikia embryos.