Effects of CO(2) enrichment on photosynthesis, growth, and biochemical composition of seagrass Thalassia hemprichii (Ehrenb.) Aschers

J Integr Plant Biol. 2010 Oct;52(10):904-13. doi: 10.1111/j.1744-7909.2010.00991.x.

Abstract

The effects of CO₂ 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 CO₂ (aq) concentrations in flow-through seawater aquaria bubbled with CO₂ . CO₂ enrichment considerably enhanced the relative maximum electron transport rate (RETR(max) ) and minimum saturating irradiance (E(k) ) of T. hemprichii. Leaf growth rate of CO₂ -enriched plants was significantly higher than that in unenriched treatment. Nonstructural carbohydrates (NSC) of T. hemprichii, especially in belowground tissues, increased strongly with elevated CO₂ (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 CO₂ treatments. In contrast, with increasing CO₂ (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 CO₂ (aq). Thus, these results indicate that T. hemprichii may respond positively to CO₂ -induced acidification of the coastal ocean. Moreover, the CO₂ -stimulated improvement of photosynthesis and NSC content may partially offset negative effects of severe environmental disturbance such as underwater light reduction.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carbon Dioxide / pharmacology*
  • Hydrocharitaceae / drug effects*
  • Hydrocharitaceae / growth & development
  • Hydrocharitaceae / metabolism*
  • Photosynthesis / drug effects*

Substances

  • Carbon Dioxide