Comparative ecophysiology of seven spring geophytes from an oak-hornbeam forest

The ecophysiological traits of seven spring forest geophytes (Gagea lutea L., Scilla bifolia L., Ficaria verna L., Corydalis cava (L.) Koerte, Arum maculatum L., Dentaria bulbifera L. Crantz, and Ornithogalum pyrenaicum L.) were compared in terms of photosynthetic performance, chlorophyll content, specific leaf area, and relative water content from early spring to summer under field conditions. Light response curves were measured for each species throughout the continuum of its phenological phases to quantify the photosynthetic photon flux density at light saturation, light-saturated photosynthetic rate and light compensation point. All species showed similar seasonal dynamics of the assessed parameters, but the average seasonal values of photosynthesis, dark respiration and maximum efficiency of the photosystem II, as well as light saturation point and light compensation point, differed significantly. From the ecophysiological parameters that were determined it appears that the investigated species can be grouped in two categories: 'early-flowering' spring ephemerals (higher P-N, I-comp, I-sat, R-d, lower F-v/F-m, more shade-avoiding strategy): G. lutea, S. bifolia, F. verna, C. cava and 'later-flowering' spring ephemerals (lower P-N, I-comp, I-sat, R-d, higher F-v/F-m, more shade-tolerating strategy): A. maculatum, D. bulbifera, and O. pyrenaicum.