Effect of Water Velocity and Light on the Growth and Development of Grateloupia livida (Harv) Yamad Carpospores

Abstract:

Grateloupia livida (Harv) Yamad is a red seaweed that has high economic value. In recent years, research on the seed production of G. livida has gained more and more attention. To further understand the progress of seed production, we studied the effects of water velocity and light on the growth and development of G. livida carpospores under the laboratory conditions. G. livida carpospores that attached for 1 d and 15 d were incubated in the water with different velocities (0, 1, 1.5, 4, 7, 10, 14 cm/s) for 20 d. The 0 cm/s group was the control group (without any water flow or under non-aerated condition). Except that the 1.5 cm/s group was controlled by aeration, all other groups were controlled by the water flow equipment. G. livida carpospores that attached for 1 d were incubated with different light intensity (35, 85, 135 µmol photons/m2·s) at different photo periods (6L:18D, 8L:16D, 10L:14D, 12L:12D, 14L:10D and 16L:8D) for 70 d. The results were described as follows: G. livida carpospores that attached for 1 d developed faster in the 0 cm/s group than in the other water velocity groups (P<0.05). The carpospores that attached for 15 d had grew and developed more slowly in the 0 cm/s group than in any other water velocity groups, and the optimum water velocity was 1.5 cm/s (P<0.05). The photo period and light intensity had a significant effect on the growth and development of G. livida carpospores and had interactive effects on the growth of the disc and plantlet (P<0.05). The optimum light condition for G. livida carpospores was 8L:16D and 10L:14D as the photo period and 35 µmol photons/m2·s as the light intensity. We recommended that the released carpospores of G. livida should be incubated in the still water for 15 d and then in the water with a velocity of 1.5 cm/s (by aeration) under the light intensity of 35 µmol photons/m2·s and photo period of 8L:16D or 10L:14D.