Abstract
The light condition in the forest understory in early spring was determined and possible acclimation of vernal species, Erythronium japonicum Dencne, inhabiting there was examined. Light intensities of the understory relative to the open were 38% and fluctuated between 113 and 913 μmol photons m-2 s-1. Fluctuations of the light intensities in the understory were predominated by 10 minutes cycle.
We compared photosynthetic characteristics of the plants acclimated to the understory with those to the open. The plants acclimated to the understory showed high maximum photosynthetic rate by 27.4% than those to the open. Their photosynthesis was induced rapidly under strong light soon after weak light for 10 minutes. Its efficiency decreased 7%. The efficiency under weak light soon after strong light decreased 10%. Soon after decreasing the light intensity, plants in the open showed temporary drop in photosynthetic rate. This result suggested development of photorespiration.
