Abstract
A sporeling culture method using gametophyte clones developed in the early 1990s led to egg discharge occurring in the dark 5 min after the start of the dark period under growth under a 11:13 L-D photoperiod. The course of egg discharge could be disturbed by light, with irradiance as low as 5–6 μmol photon m−2 s−1 causing 75–80% of the discharged eggs to detach from the oogonia and consequently to die within several hours. In order to enhance outgrowth rate of young sporophytes, a study was conducted to test the effect of controlling darkness in the period 2–3 h after dusk. When the slides were transferred from the standard 11:13 L-D regime to continuous light, eggs were discharged 5 min after the end of the light phase and peaked 5–l5 min later on first day after transfer, indicating that the female gametes “remember” the light-dark regime. This suggests the existence of an endogenous circadian rhythm. During the second and third days, very few eggs were discharged throughout the 11 h of the normal light phase of the L-D regime, indicating the inhibitory effect of continuous light and that the rhtyhm is easily damped by light.
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Li D, Liu H, Peng G, Wu C (1998) Application of gametophyte clones of Japanese strain Undaria pinnatifida to large scale sporeling production. Mar. Sci. 5: 4–5 (in Chinese).
Lüning K (1981) Egg release in gametophytes of Laminaria saccharina induction by darkness and inhibition by blue light and U.V. Br. Phycol. J. 16: 379–393.
Pang S, Hu X, Wu C, Hirosawa A, Ohno M (1997) Intraspecific crossing of Unidaria pinnatifida (Harv.) Sur. –A possible time-saving way of strain selection. Chinese J. Oceanol Limnol 15(3): 227–235.
Pang S, Wu C (1996) Study on gametophyte vegetative growth of Unidaria pinnatifida and its application. Chinese J Oceanol Limnol 14(3): 205–210.
Provasoli L. (1968) Media and prospect for the cultivation of marine algae. In Watanabe A, Hattori A (eds), Cultures and Collection of Algae. Proceedings of the U.S.- Japan Conference. Hakone, Japanese Society of Plant Physiology 63–75.
Wu C (1998) Seaweed resources of China. In Critchley A, Ohno M (eds), Seaweed Resources of the World. Jap. Inter. Cooperation Agency, Yokosuka, Japan, pp. 34–46.
Wu C, Gao N, Cheng D, Chou B, Cai P, Dong S, Wen Z, Cong R (1979) On the malformation disease of Laminaria sporelings. Oceano. et Limnol. Sinica. 10(3): 238–253, (in Chinese).
Wu C, Pang S (1994) On the cultivation of Undaria gametophyte clones and its use in sporeling raising. In Wang S (ed.), Seaweed Biotechn. Shanghai Science and Technology Press, Shanghai, China, 112–115, (in Chinese).
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Liu, J., Dong, L., Shen, Y. et al. Effect of light period on egg-discharge of gametophyte clones of Undaria pinnatifida (Phaeophyta). J Appl Phycol 16, 519–521 (2004). https://doi.org/10.1007/s10811-004-5560-6
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DOI: https://doi.org/10.1007/s10811-004-5560-6