학술논문
The effects of desiccation and salinity gradients on the PSII photochemical efficiency of an intertidal brown alga, Sargassum fusiforme from Kagoshima, Japan.
Document Type
Article
Source
Subject
*PULSE amplitude modulation
*SARGASSUM
*SALINITY
*BROWN algae
*PHOTOSYSTEMS
*HUMIDITY
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Language
ISSN
1322-0829
Abstract
SUMMARY: The responses of photochemical efficiency to desiccation and salinity gradients in an intertidal edible brown macroalga, Sargassum fusiforme (Harvey) Setchell (Sargassaceae, Fucales), were determined using a pulse amplitude modulation (PAM)‐chlorophyll fluorometer. The effective quantum yields (ΔF/Fm'; = ΦPSII) of photosystem II (PSII) dropped to zero after 360‐min aerial exposure under low irradiance (20 μmol photons m−2 s−1) and 120‐min exposure under high irradiance (700 μmol photons m−2 s−1) for this species at 20°C and 50% relative humidity. Under these conditions, ΔF/Fm' failed to recover to initial levels even after 1‐day rehydration in seawater. In general, ΔF/Fm' decreased as desiccation reduced the absolute water content (AWC, %). Nevertheless, when AWC was above ca. 20%, ΔF/Fm' was mostly restored to initial levels after 1‐day rehydration in seawater, suggesting strong tolerance to dehydration. Furthermore, S. fusiforme appeared to tolerate a broad range of salinity (i.e. 15–50 psu) during six days of culture; however, ΔF/Fm' declined when salinity was <10 and 60 psu. Strong tolerance to dehydration and salinity stress likely provides S. fusiforme an advantage that allows it to flourish in the intertidal habitat. [ABSTRACT FROM AUTHOR]