L I C H E N   page of the Department of Plant Physiology and anatomy

          PLEASE NOTE: the page is devoted to those people who are involved into ecophysiology
          of lichens
           
            • Project description
            • Objectives of the project
            • Methods
            • Supporting items (team, facilities, instruments, some photos, publications)
            • more to be filled later
          Brief characterization of planned project (2002-2005)
          The project is focused on the analysis of photoprotective mechanisms activated  in lichen thalli under high light. Those mechanism related to (1) hyphal cortex layer and exclusively to (2) photobiont will be studied separately. Measurements of changes in spectral reflectance with ongoing thalli dessication and determination of amount and role of pigments and fungi secondary metabolits will be done. Photoprotective mechanism related to photobiont will be studied using fluorometric and biochemical methods. We consider application of several fluorometric methods combined with evaluation of the amount of xanthophyll cycle pigments during high light stress induced under laboratory conditions. We expect that photoinhibition of photosynthesis will occur under high light, low temperature and high hydration of studied lichen species. Using fluorometric method, the phenomenon of photoinhibition and recovery from photoinhibition will be studied and limiting factors of photoinhibition will be evaluated. Within the project, also determination of heterogeneity of chlorophyll fluorescence (kinetic CCD camera) and photosynthetic activity (fluorometric and gas exchange methods) will be done in order to quantify the photosynthetic performance of  young and old thallus parts. For extrapolation of laboratory results to real outdoor conditions, field  measurements of diurnal courses of chlorophyll fluorescence parameters and gas exchange measurements will be made.

          Main objectives of planned research (2002-2005)
          The main objective of the proposed project related to ecophysiology of lichens is to evaluate the extent of

            (1) photoinhibition
            (2) mycobiont-related  photoprotective mechanism
            (3) photobiont-related photoprotective mechanisms
          in foliose green-algal lichens exposed to extreme environmental conditions, such as: low and high thalii hydration, low and high thalli temperature.

          Particular objectives and hypotheses to be proved

            (1)To prove that most severe photoinhibition in lichens occurs under low temperature and full hydration. The hypothesis will be tested under laboratory conditions and in the field.
            (2) To prove that there is UV-B related photoinhition in lichens.
            (3)To prove that the extent of lichen photoinhibition is modulated by selective radiation filtration by the upper hyphal cortex, xanthophyll cycle pigments and antioxidants pools.
            (4)To prove intrathalline heterogeneity in actual rate of net photosynthesis and relate it to photobiont amount and distribution.
            (5)To prove that under low temperature, there is enhanced negative effect of photoinhibition in PS I compared to PS II.
            (6)To prove (combining laboratory and field measurements) that survival strategies of lichens depend mostly on adaptation capability to tolerate extremely low/high temperature.

          Supporting items

          Team members (+ fields of responsibility)

            • M. BARTAK, Assoc.Prof.  (fluorometric methods, gas exchange methods, ecophysiology in the lab/field)
            • J. GLOSER, Prof. (Gas exchange methods, spectral reflectance methods, ecophysiology in the lab/field, photoprotective pigments and antioxidants evaluation)
            • J. DUBOVA, Dr.  (Thallus anatomy of lichens, image analysis)
            • O. KOMAREK, Dr. (algologist, cultivation and determination of extracted photobionts)
            • P. ILIK, Dr. - Palacky Univ. Olomouc (low/high temperature fluorescence)

              •  
            • J. HAJEK, Mgr. - Ph.D. student (fluorometric methods, temperature dependence of lichen photosynthesis)
            • H. VRABLIKOVA - student (fluorometric methods with respect to lichen photoinhibition)
            • I. MUSILOVA - student (foliose lichen anatomy)
            • A. KOCMANOVA - student (low temperature effects on lichen physiology)
          Background of the team in particular methods (few examples of recent lichen physiology studies)

                  (1) Chlorophyll fluorescence
           

                  Light response curves of gross photosynthesis (GP) mesured on thallus of Cetraria islandica. Full thallus hydration
                 (0 % of water saturation deficit, WSD) is indicated in green(o), slightly dehydrated thallus is indicated in orange (o), and
                 violet (o), severe dehydration of thallus (71 % WSD) is indicated in  red (o). GP data points were calculated from
                 quantum yield of photosystem II photochemistry (FII) measured by a  fluorometer PAM-2000.
                 Ref: Hajek-Bartak-Gloser: MS submitted to Photosynthetica.

            (2) Pigments analyses
             

            Timecourse of deepoxidation state of xanthophyll cycle pigments ( Zea + 0.5 Anthera / (Viola + Anthera +Zea)) after photoinhibitory treatment ( 30 min exposition to 1000 mmol m-2 s-1 at 18 degree C) of algal photobiont Trebouxia sp. isolated from foliose lichen species Umbilicaria hirsuta and cultivated on TR medium. Photoinhibitory treatment lasted from time 0 to 0.5 h. Abbreviations: Zea = zeaxanthin, Anthera = antheraxanthin, Viola = violaxanthin. Source: Vrablikova, Bartak (unpublished)
            (3) Gazometric methods
            (4) Chlorophyll fluorescence imaging
             
              CCD fluorometric camera image of Lasallia pustulata thallus showing contrasting
              differences of variable fluorescence (Fv) distribution (maximum Fv is found in in central, close-to-umbilicus part of thallus /red, yellow/, minimum Fv is found in marginal parts /deep blue/ - Bartak et Hajek, unpublished).


            (5) Anatomy of lichen thallus

              Cross-cut section of thallus
              of foliose lichen (Hypogymnia physodes) showing /from top to bottom/ 1)upper cortex layer (blue and yellow),  2)Trebouxia cells layer (orange), 3)medulla (yellowish blue), (4)lower cortex (yellow and blue). Source: Dubova et al. (unpublished).
            (6) Cultivation of extracted photobiont (Trebouxia sp.)
             

              Cells of Trebouxia sp. isolated from Umbilicaria hirsuta at different stages og their reproduction cycle:
              left: free swimming zoospores, center: non-motile vegetative cells right: mature cells (the biggest ones)
               
          Former research projects of M. Bartak
           
            Project related to global changes
              95045 Growth and development of clonal plants in normal and polluted sites. U.S.-Czech
                              Science and Technology Program. (J. Gloser - principal co-investigator, M. Bartak, M. Balaz -
                              co-investigators) 1995
              0757/1998 Effect of global changes (elevated concentration of CO2) on physiology of plant
                      growth and production. (M. Bartak - principal investigator) 1998

            Projects related to plant ecology

              0757/1998 Ecology of antarctic coastal oasis (P. Prosek - principal investigator, M. Bartak - co-investigator) 1998
            Projects related to teaching of plant physiology
              0606/1996 The Introduction of New Methods into the Teaching of Photosyntesis. Principal
                              investigator Gloser, J., co-investigator: Bartak, M.
              0411/97 Inovation of the Teaching of Productional Plant Ecology: Modelling of Physiological
              and Productional Processes. Principal investigator: Bartak, M., 1997
              0462/1999 Modernisation of teachning plant physiology with special respect to photosynthesis.
                             (M. Bartak - principal investigator) 1999
           
            Other projects
              501/94/0493 Ecophysiological Aspects of Reforestation in Heavily Acidified Environments.
                              Principal investigator: Gloser, J., co-investigators: Vicherkova , M., Plhak, F., Kousalova , I.,
                              Bartak, M.
               204/94/0385 Clear-Cut Grass Vegetation and Soil Interaction Under Different Immision
                               Impacts. Principal co-investigator: Gloser, J., co-investigator: Bartak, M. A joint project with the
                               Institute of Landscape Ecology of the Academy of Sciences and the University of Agriculture and
                               Forestry, Brno. 1994-1996
              521/97/0284 Did quantitative parameters of photosynthetic CO2 fixation and nitrogen
                              metabolism change during the evolution of the Triticum genus? (J. Gloser - principal
                              co-investigator, M. Bartak - co-investigator), 1997-1999.

          Publications

          • see either  full list of publication of the staff (including abstract titles from conferences) or
          • personal list of publication (only journal publication)
          • Lichen physiology-related publications
              • Bartak, M., Hajek, J., Gloser, J. (1999): Application of fluorometric methods to measurements of lichen photosynthetic responses to changing temperature and thallus hydration. In: Ecology of Antarctic Coastal Oasis. Book of Abstracts, p. 5.

              Bartak, M., Hajek, J., Gloser, J.(2000): Application of fluorometric methods to measurements of lichen photosynthetic responses to changing  temperature and thallus hydration. In: Ecology of Antarctic Coastal Oasis. Proceedings, 2000, p. 17-26.

              Bartak, M., Hajek, J., Vrablikova, H., Gloser, J. (2000): Photosynthetic response of lichenized Trebouxia sp. (Umbilicaria decussata (Vill.) Zahlbr.) from maritime Antarctica to high light stress. Abstracts. Conference:  Algae and Extreme Environments - Ecology and Physiology. Třeboň, Sept 11-16, 2000, Czech Republic, p. 40.

              Hajek, J., Bartak, M. (2000): Distributional pattern of unicellular algal photobiont within the thalli of fruticose and foliose lichens. Abstracts. Conference: Prof. Němecs  Cytological Day, Brno, May 25, 2000, Czech Republic. p.16.

              Hajek, J., Bartak, M., Gloser, J. (2000): Species-specific photosynthetic response of lichens to desiccation and temperature change detected by changes in chlorophyll fluorescence parameters. Abstracts. 12th FESPP Congress, Budapest, August, 2000, Hungary. Plant Physiology and Biochemistry, 38(suppl.): p.193.

              Barták, M., Hájek, J., Gloser, J. (2000): Heterogeneity of chlorophyll fluorescence over thalli of several foliose macrolichens exposed to adverse environmental factors: Interspecific differences as related to thallus hydration and high irradiance. Photosynthetica, 38: (accepted, in print).

              Hajek, J., Bartak, M., Gloser, J.: Effects of thallus temperature and hydration on photosynthetic parameters of Cetraria islandica from contrasting habitats. Photosynthetica (submitted).

              Bartak, M., Dubova, J., Hajková, M., Hajek, J., Musilova, I.: Intrathalline distribution of an alga Trebouxia sp. and  its photosynthetic parameters in Lasallia pustulata and Umbilicaria decussata. Abstract. 52nd Conference of the Polish Botanical Society, Poznan, Poland, 2001 (submitted).

              Bartak, M., Hajek, J., Vrablikova, H.: Low temperature photoinhibition and recovery in fruticose (Usnea antarctica) and foliose (Umbilicaria decussata) Antarctic lichen species. Abstracts. 9th Days of Plant Physiology, Ceske Budejovice, Czech Republic, 2001 (submitted).

              Hajek, J., Bartak, M., Gloser, J.: Photosynthetic response of Iceland moss  (Cetraria islandica) to thallus temperature and hydration detected by chlorophyll fluorescence. Abstracts. 9th Days of Plant Physiology, Ceske Budejovice, Czech Republic, 2001 (submitted).
               

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