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

摘要

cqvip: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.