PHOTOSYNTHETIC CHARACTERISTICS OF THE RESURRECTION PLANT HABERLEA RHODOPENSIS FROM TWO HABITATS

摘要

The photosynthetic characteristics of Haberlea rhodopensis plants from two habitats in Western Rhodope Mountain (in the regions of Trigrad and Wonderful bridges) were studied. Although the plants from both habitats were exposed to sun during part of the day, their leaves were morphologically similar to those of shade plants. The desiccation-induced damages on membrane integrity were characterized by electrolyte leakage and lipid peroxidation. Photochemical activity, energy distribution between the two photosystems and physicochemical properties of thylakoid membranes were estimated by means of chlorophyll fluorescence, 77K fluorescence and particle microelectrophoresis measurements. The mutual organization of PSI-LHCI and PSII-LHCII complexes and spillover between them were similar in thylakoids isolated from well-hydrated plants from Trigrad and Wonderful bridges. Under desiccation up to 8% RWC the F735/F685 ratio at excitation with 472 nm (chl b) remained almost unchanged in thylakoid membranes from Wonderful bridges while it decreased considerably in thylakoid membranes from Trigrad. The thylakoid membranes from Wonderful bridges showed a less alteration in energy distribution between both photosystems in response to dehydration. Dehydration induced stronger modifications in thylakoid membranes of plants from Trigrad, expressed by higher electrolyte leakage, lipid peroxidation and membrane surface charge density.