Photon-harvesting efficiency and arbuscular mycorrhiza in amphibious plants (original) (raw)
The amphibious plant species of intermittent aquatic habitats thrive both submerged and emerged. In order to outline the adaptive characters of these two life forms photochemical efficiency of photosystem 2, leaf contents of chlorophyll (Chl) a and b, carotenoids (Car), anthocyanins (Ant), and UV-B absorbing compounds (UV-B abs), and root aerenchyma and arbuscular mycorrhizal (AM) colonisation were studied in Glyceria fluitans, Gratiola officinalis, Ranunculus lingua, Teucrium scordium, Sium latifolium, Sparganium emersum, and Veronica anagallis-aquatica. Water level fluctuations did not exert a severe effect on photon harvesting efficiency. Submerged specimens had higher contents of Car and Ant whereas higher contents of UV-B abs were found in emerged specimens indicating efficient protection against the harmful effects of solar radiation. Roots of all species studied had extensive aerenchyma and were colonised by AM fungi, which were significantly more abundant in emerged specimens. This is the first report on AM symbiosis in S. latifolium and S. emersum. /F m of PS2 -potential photochemical efficiency; M% -mycorrhizal intensity; PS -photosystem; SLA -specific leaf area; Y -actual photochemical efficiency of PS2. Acknowledgements: This research was financed by the Ministry of Education, Science and Sport, Republic of Slovenia, through the programmes "Biology of plants" (P1-0212) and "Young researchers" (3311-03-831202 and 3311-04-831248). The authors thank undergraduate students U. Godec, U. Kačar, M. Klemenc, P. Maurič, and M. Pociecha for help with analyses, and to Dr Roger Pain for revising the English writing.