The Role of Polyamines in pH Regulation in the Extracellular Calcifying Medium of Scleractinian Coral Spats.

This study aims to elucidate a novel mechanism for elevating the pH within the calicoblastic extracellular calcifying medium (pH) of corals and demonstrate the potential contribution of calcifying organisms to CO sequestration. Departing from traditional models that attribute the increase in pH primarily to H expulsion via Ca-ATPase, we emphasize the significant role of polyamines. These ubiquitous biogenic amines conveyed by calicoblastic cells through polyamine transporters demonstrate a remarkable affinity for CO.

Interspecific variation in Rubisco CO/O specificity along the leaf economic spectrum across 23 woody angiosperm plants in the Pacific islands.

The coordinated interspecific variation in leaf traits and leaf lifespan is known as the leaf economic spectrum (LES). The limitation of CO diffusion to chloroplasts within the lamina is significant in C photosynthesis, resulting in a shortage of CO for Rubisco. Although Rubisco CO/O specificity (S) should be adaptively adjusted in response to the interspecific variation in CO concentrations [CO] associated with Rubisco, S variations across species along the LES remain unknown.

Atmospheric CO captured by biogenic polyamines is transferred as a possible substrate to Rubisco for the carboxylation reaction.

Biogenic polyamines are involved in a wide range of plant cellular processes, including cell division, morphogenesis and stress responses. However, the exact roles of biogenic polyamines are not well understood. We recently reported that biogenic polyamines that have multiple amino groups can react with CO and accelerate calcium carbonate formation in seawater.

Short-term effects of high CO2 accelerate photosynthetic induction in Populus koreana × trichocarpa with always-open stomata regardless of phenotypic changes in high CO2 growth conditions.

Long-term high CO2 exposure accelerates photosynthetic induction response due to rapid light increase. However, it is unclear whether the acceleration is caused by acclimation of photosynthetic components (long-term CO2 effect) and/or by the sufficient substrate under high CO2 at the measurement (short-term CO2 effect). Populus koreana × trichocarpa cv.