Effects of temporary and periodic emersion on the growth of Fucus spiralis and Pelvetia canaliculata germlings

doi:2011.26.2.193

Algae > Volume 26(2); 2011 > Article

Algae 2011;26(2): 193-200. doi: https://doi.org/10.4490/algae.2011.26.2.193

Bo Yeon Kim¹, Seo Kyoung Park¹, Trevor A. Norton² and Han Gil Choi¹^,*

¹Faculty of Biological Science and Institute of Basic Sciences, Wonkwang University, Iksan 570-749, Korea
²School of Biological Sciences, University of Liverpool, Port Erin, Isle of Man, IM9 6JA, UK

*Corresponding Author

Email: hgchoi@wku.ac.kr

ABSTRACT

The stress tolerance ability of Pelvetia canaliculata (L.) Dcne. Et Thur. and Fucus spiralis L. to temporary and periodic emersion stress was examined in order to test the following hypotheses: The upper shore alga, P. canaliculata is more tolerant to desiccation than F. spiralis in the germling stage and the former outgrows the latter under desiccation stress; Germling stress tolerance of the two species is age-specific; Crowding of germlings protects them from desiccation, irrespective of the species involved. Germling growth of the two species was retarded with increasing exposure period and was age-specific, as they were air-exposed at an earlier stage. After 16 days, the length of Pelvetia germlings was similar between 2-day-old germlings (125-140 μm) and 7-day-old germlings (134-140 μm), which were air-exposed during the same period (0, 6, 12, 24, 48, and 72 h) at the two different ages. However, Fucus germlings were significantly larger at 7-day-old germlings (211-277 μm) than at 2-day-old germlings (184-278 μm), especially in the treatments of 48 and 72 h. These results indicate that Fuscus grow faster than Pelvetia and that the growth response of germlings to temporary emersion stress is more sensitive in Fucus than that in Pelvetia. Growth of germlings of both species was reduced with increasing density under favorable growth conditions (submerged control and 6 h / 12 h exposure treatments) in the periodic air-exposed experiments using tidal tanks, but was enhanced under severe emersion stress conditions. P. canaliculata showed better growth at 6 h exposure treatment than that of the control, under continuous submergence, indicating that Pelvetia germlings require a periodic exposure period. Fucus germlings always grew faster than those of Pelvetia and did best in mixed cultures, whereas Pelvetia did least well when mixed with Fucus germlings. The adverse effects of F. spiralis on P. canaliculata were greater than those of Pelvetia cohorts. The outcome of interspecific competition between F. spiralis and P. canaliculata gemlings was slightly altered by exposure period but not to such an extent as to change the outcome.

Key words: density; desiccation; Fucus spiralis; germling; growth; Pelvetia canaliculata