Persistent stimulation of photosynthesis in short rotation coppice mulberry under elevated CO2 atmosphere

Abstract

Current study was undertaken to elucidate the responses of short rotation coppice (SRC) mulberry under elevated CO2 atmosphere (550μmolmol−1). Throughout the experimental period, elevated CO2 grown mulberry plants showed significant increase in light saturated photosynthetic rates (A′) by increasing intercellular CO2 concentrations (Ci) despite reduced stomatal conductance (gs). Reduced gs was linked to decrease in transpiration (E) resulting in improved water use efficiency (WUE). There was a significant increase in carboxylation efficiency (CE) of Rubisco, apparent quantum efficiency (AQE), light and CO2 saturated photosynthetic rates (AMAX), photosynthetic nitrogen use efficiency (PNUE), chlorophyll a fluorescence characteristics (FV/FM and PIABS), starch and other carbohydrates in high CO2 grown plants which clearly demonstrate no photosynthetic acclimation in turn resulted marked increase in above and below ground biomass. Our results strongly suggest that short rotation forestry (<1year) with mulberry plantations should be effective to mitigate raising CO2 levels as well as for the production of renewable bio-energy.