Portal de Periódicos da CAPES

UV-B tolerance of bryophyte species with different degrees of desiccation tolerance

1999; Elsevier BV; Volume: 48; Issue: 2-3 Linguagem: Inglês

10.1016/s1011-1344(99)00029-9

1873-2682

Zoltán Takács, Zs. Csintalan, L. Sass, Éric Laitat, Imre Vass, Z. Tuba,

Biocrusts and Microbial Ecology

We report on the efficiency of the primary photochemistry of photosystem II and potential thylakoid activity (represented by the variable fluorescence decrease ratio) of seven UV-B-treated bryophyte species during exposure and the subsequent recovery period. In Tortula ruralis, a strongly desiccation-tolerant grassland moss, there is no indication of any effects of UV-B irradiation. Desiccation-tolerant forest mosses (Polytrichum formosum, Mnium hornum) are only temporarily affected by UV-B radiation or can even be positively affected by it (Dicranum scoparium). The protective mechanism of desiccation-sensitive mesic species (Plagiothecium undulatum, Leucobryum glaucum, Pellia epiphylla) is rapidly exhausted and they cannot tolerate increased UV-B radiation. These results support our view presented here that desiccation tolerance and UV-B tolerance involve similar defence mechanisms.