The effects of enhanced UV-B radiation on UV-absorbing compounds (UVAC), the maximum quantum yield of photosystem II (Fv/Fm), DNA integrity, and the sclerophylly index, were analyzed in the mosses Bryum pseudotriquetrum and Fontinalis antipyretica. The study was performed for 31 days under laboratory conditions. Enhanced UV-B increased the bulk level of the vacuolar soluble UVAC (SUVAC) in both mosses and the concentration of two different soluble kaempferols in B. pseudotriquetrum. However, enhanced UV-B had no effect on the bulk level of cell wall-bound insoluble UVAC (WUVAC) in both mosses and the concentration of insoluble p-coumaric acid in F. antipyretica. Thus, the insoluble fraction would be less UV-B-responsive than the soluble one. This probably happened because (1) the constitutively high bulk level of WUVAC (and noticeably higher than that of SUVAC) would already provide a sufficiently effective protection; and (2) WUVAC would be relatively immobilized in the cell wall, which would limit the reaction capacity of these compounds to UV-B. The protective mechanisms developed by both mosses could not totally prevent UV-B damage, which was indicated by the modest decrease of Fv/Fm and the increase in DNA damage. We discuss the ecological and phylogenetic implications of the differences in UVAC compartmentation between liverworts and mosses.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 33 • No. 2