The intertidal macroalga Enteromorpha compressa showed the ability to use HCO 3 − as an exogenous inorganic carbon (Ci) source for photosynthesis. However, although the natural seawater concentration of this carbon form was saturating, additional CO 2 above ambient Ci levels doubled net photosynthetic rates. Therefore, the productivity of this alga, when submerged, is likely to be limited by Ci. When plants were exposed to air, photosynthetic rates saturated at air‐levels of CO 2 during mild desiccation. Based on carbon fixing enzyme activities and Ci pulsechase incorporation patterns, it was found that Enteromorpha is a C 3 plant. However, this alga did not show O 2 inhibited photosynthetic rates at natural seawater Ci conditions. It is suggested that such a C 4 ‐ like gas exchange response is due to the HCO 3 − utilization system concentrating CO 2 intracellularly, thus alleviating apparent photorespiration.
No takes yet. Share an insight, caveat, or question.
Beer et al. (1987) studied this question.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: