SUNFLECK FREQUENCY AND DURATION AFFECTS GROWTH-RATE OF THE UNDERSTOREY PLANT, ALOCASIA-MACRORRHIZA

1. We measured the gas exchange and growth responses of Alocasia macrorrhiza to three light regimes; short lightflecks (SF), long lightflecks (LF), and uniform diffuse light (U), all with the same total daily photon flux density. 2. Relative growth rates (RGR) were highest in the U regime and lowest in the LF regime. Carbon gain was limited by low photosynthetic induction state in the LF plants. A greater contribution from post-illumination CO2 fixation resulted in increased RGR for the SF plants relative to the LF plants. 3. Photosynthetic capacities and efficiency of sunfleck utilization were unaffected by growth light regime, indicating that there was no acclimation to the temporal distribution of light. In addition, we did not find any differences in carbon allocation patterns which could be attributed to acclimation. 4. We conclude that although sunfleck frequency and duration have substantial effects on carbon gain and growth of A. macrorrhiza, specific acclimation responses have not developed.