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

1. We measured the gas exchange and growth responses of Alocasia macro rrhiza to three light regimes; short lightflecks (SF), long lightfleck s (LF), and uniform diffuse light (U), all with the same total daily p hoton 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 contributio n from post-illumination CO2 fixation resulted in increased RGR for th e SF plants relative to the LF plants. 3. Photosynthetic capacities an d efficiency of sunfleck utilization were unaffected by growth light r egime, indicating that there was no acclimation to the temporal distri bution of light. In addition, we did not find any differences in carbo n allocation patterns which could be attributed to acclimation. 4. We conclude that although sunfleck frequency and duration have substantia l effects on carbon gain and growth of A. macrorrhiza, specific acclim ation responses have not developed.