Physiological adaptation before and after snow melt in green overwintering leaves of some alpine plants

Horn

2005

S. 139-156

6 Abb., 2 Tab., 38 Lit. Ang.

Artikel aus einer ZeitschriftUnselbständiges Werk

200138867

The physiological adaptation of Homogyne alpina, Loiseleuria procumbens and Rhododendron ferrugineum plants that were collected at altitudes between 2000 m and 2200 m in the Central European Alps was studied in field samples as it occurs before and after snow melt. These plants retain green leaves over the winter, well protected by snow, but showing some photosynthetic functions. During snow melt in May and June the leaves are suddenly exposed to markedly increased irradiation intensities of PAR and UV-B and to a significant increase in leaf temperature (up to 40 K). This sudden change in microclimate had no detrimental influence on the investigated photosynthetic parameters. Measurements of plastid pigments, fluorescence parameters and of antioxidant and flavonoid compounds revealed a species - specific response. The two woody dwarf shrubs Loiseleuria and Rhododendron behaved more similar as compared to Homogyne.