Drought-hardening in the upper-shore seaweeds Fucus spiralis and Pelvetia canaliculata

• Published in: The Journal of ecology 1979-01, Vol.67 (2), p.687-696
• Main Authors: Schonbeck, M.W, Norton, T.A
• Format: Article
• Language: English
• Subjects: Algae; Dehydration; Drying; Oxygen; Plant growth; Plants; Relative humidity; Sea water; Seaweeds; Thallus
• ISSN: 0022-0477; 1365-2745
• DOI: 10.2307/2259120

(1) Variations in the ability of the high-shore fucoid algae Pelvetia canaliculata (L.) Decn. et Thur. and Fucus spiralis L. to tolerate tissue dehydration were investigated, to determine whether environmental conditions can induce drought-hardening. Plants were collected from different levels on the shore, and at different times of year, and their performance in culture was assessed following experimental desiccation. Drought-tolerance was found to be greater in plants from the highest levels on the shore, and to vary seasonally, increasing in the spring, becoming maximal in summer and lessening in winter. (2) Experimental hardening of Fucus spiralis confirmed that tolerance develops in response to subcritical desiccation. De-hardening also took place in plants moved to physiologically less-stressed conditions, as when plants were moved to below their normal zone on the shore or kept permanently submerged in laboratory culture. (3) The percentage dry-matter content of the tissues was found to correlate positively with drought-tolerance and to show the same seasonal fluctuation, but no causal relationship could be established. Experimental hardening caused dry-matter content to increase, but a similar increase was associated with a period of curtailed growth and did not always confer added drought-tolerance.