PHOTOSYNTHETICA

Photosynthetica 2016, 54(3):430-437 | DOI: 10.1007/s11099-015-0181-7

Photosynthetic responses of the low intertidal macroalga Sargassum fusiforme (Sargassaceae) to saline stress

S. Gao^1,2, L. Huan^1,2, X. P. Lu^1,2, W. H. Jin¹, X. L. Wang^1,2, M. J. Wu³, G. C. Wang^1,2,*

¹ Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China

² Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China

³ Zhejiang Provincial Key Lab for Water Environment and Marine Biological Resources Protection, College of Life and Environment Science, Wenzhou University, Wenzhou, China

Sargassum fusiforme, a species of brown seaweed with economic importance, inhabits lower intertidal zones where algae are often exposed to various stresses. In this study, changes in the photosynthetic performance of S. fusiforme under saline stress were investigated. The PSII performance in S. fusiforme significantly improved, when the thalli were exposed to 0% salinity, and remained high with prolonging treatment time. In contrast, the PSII activity declined considerably under salinities of 4.5 and 6%. The PSI activity did not change remarkably under saline stress, thus demonstrating higher tolerance to saline stress than PSII. In addition, the PSI activity could be also restored after saline treatments, when PSII was inhibited by 3-(3,4-dichlorophenyl)-1,1-dimethylurea. It might be as a result of changes in the NAD(P)H content in the thalli under saline stress. Our results suggested that PSI was much more tolerant to different saline stress than PSII in S. fusiforme. We demonstrated that S. fusiforme was much more tolerant to hyposaline than to hypersaline stress.

Keywords: chlorophyll fluorescence; chrysolaminarin; electron transport rate; nonphotochemical quenching; reductant

Received: June 30, 2015; Accepted: October 20, 2015; Published: September 1, 2016Show citation