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Effects of CO 2 Enrichment on Photosynthesis, Growth, and Biochemical Composition of Seagrass Thalassia hemprichii (Ehrenb.) Aschers
Author(s) -
Jiang Zhi Jian,
Huang XiaoPin,
Zhang JingPing
Publication year - 2010
Publication title -
journal of integrative plant biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.734
H-Index - 83
eISSN - 1744-7909
pISSN - 1672-9072
DOI - 10.1111/j.1744-7909.2010.00991.x
Subject(s) - seagrass , photosynthesis , nitrogen , botany , seawater , biology , carbon dioxide , potamogetonaceae , chemistry , environmental chemistry , zoology , horticulture , ecology , ecosystem , organic chemistry
The effects of CO 2 enrichment on various ecophysiological parameters of tropical seagrass Thalassia hemprichii (Ehrenb.) Aschers were tested. T. hemprichii , collected from a seagrass bed in Xincun Bay, Hainan island of Southern China, was cultured at 4 CO 2 (aq) concentrations in flow‐through seawater aquaria bubbled with CO 2 . CO 2 enrichment considerably enhanced the relative maximum electron transport rate (RETR max ) and minimum saturating irradiance (E k ) of T. hemprichii . Leaf growth rate of CO 2 ‐enriched plants was significantly higher than that in unenriched treatment. Nonstructural carbohydrates (NSC) of T. hemprichii , especially in belowground tissues, increased strongly with elevated CO 2 (aq), suggesting a translocation of photosynthate from aboveground to belowground tissues. Carbon content in belowground tissues showed a similar response with NSC, while in aboveground tissues, carbon content was not affected by CO 2 treatments. In contrast, with increasing CO 2 (aq), nitrogen content in aboveground tissues markedly decreased, but nitrogen content in belowground was nearly constant. Carbon: nitrogen ratio in both tissues were obviously enhanced by increasing CO 2 (aq). Thus, these results indicate that T. hemprichii may respond positively to CO 2 ‐induced acidification of the coastal ocean. Moreover, the CO 2 ‐stimulated improvement of photosynthesis and NSC content may partially offset negative effects of severe environmental disturbance such as underwater light reduction.