Abstract:

In order to discovery the photosynthetic mechanism of shade plants to through light and heat stress. This paper studied the photosynthetic physiology and structure of spring leaves and autumn leaves leaf of saxifrage late in October with LI-6400 photosynthesis system and paraffin section method. The results showed that, photosynthetic rate, stomatal conductance of spring leaves were significantly lower than autumn leaves, and reduce of photosynthetic rate limited by stomatal factor. Spring leaves compensation point was 14.3 μmol photons/(m2?s), and light saturation point was 346 μmol photons/(m2?s) by Pn-PAR curves, indicating that spring leaves had better tolerance on high light. Anatomical structures showed that the spring leaves had a significant increase in the meat tissue, but the palisade lower than the autumn, which confirmed the consistency of morphological structure and physiological of saxifrage leaves.