title: Leaf photoacclimatory responses of the tropical seagrass Thalassia testudinum under mesocosm conditions: a mechanistic scaling-up study.
abstract: Here, the leaf photoacclimatory plasticity and efficiency of the tropical seagrass Thalassia testudinum were examined. Mesocosms were used to compare the variability induced by three light conditions, two leaf sections and the variability observed at the collection site. The study revealed an efficient photosynthetic light use at low irradiances, but limited photoacclimatory plasticity to increase maximum photosynthetic rates (P(max)) and saturation (E(k)) and compensation (E(c)) irradiances under high light irradiance. A strong, positive and linear association between the percentage of daylight hours above saturation and the relative maximum photochemical efficiency (F(V)/F(M)) reduction observed between basal and apical leaf sections was also found. The results indicate that T. testudinum leaves have a shade-adapted physiology. However, the large amount of heterotrophic biomass that this seagrass maintains may considerably increase plant respiratory demands and their minimum quantum requirements for growth (MQR). Although the MQR still needs to be quantified, it is hypothesized that the ecological success of this climax species in the oligotrophic and highly illuminated waters of the Caribbean may rely on the ability of the canopy to regulate the optimal leaf light environment and the morphological plasticity of the whole plant to enhance total leaf area and to reduce carbon respiratory losses.
authors: Laboratorio de Fotobiología, Unidad Académica Puerto Morelos, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Apto. Postal 1152, 77500-QR Cancún, Mexico.
authors: Napo M
authors: NM
authors: Cayabyab
authors: Laboratorio de Fotobiología, Unidad Académica Puerto Morelos, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Apto. Postal 1152, 77500-QR Cancún, Mexico.
authors: Susana
authors: S
authors: Enríquez
mesh_terms: D000064:Acclimatization; D031321:Hydrocharitaceae / Q000254:growth & development / Q000502:physiology / Q000528:radiation effects*; D018527:Hydroponics; D008027:Light; D010788:Photosynthesis / Q000528:radiation effects*; D018515:Plant Leaves / Q000254:growth & development / Q000502:physiology / Q000528:radiation effects
references: Abal EG, Loneragan N, Bowen P, Perry CJ, Udy JW, Dennison WC. 1994. Physiological and morphological responses of the seagrass Zostera carpricorni Aschers. to light intensity. Journal of Experimental Marine Biology and Ecology 178: 113-129.
references: Agawin NSR, Duarte CM, Fortes MD. 1996. Nutrient limitation of Philippine seagrasses (Cape Bolinao, NW Philippines): in situ experimental evidence. Marine Ecology Progress Series 138: 233-243.
references: Bjørkman Ø. 1981. Responses to different quantum flux. In: Lange OL, Nobel PS, Osmond CB, Ziegler H, eds. Encyclopedia of plant physiology, Vol. 12A. New series. Berlin, Germany: Springer-Verlag, 57-107.
references: Bjørkman Ø, Demming B. 1987. Photon yield of O2 evolution and chlorophyll fluorescence characteristics at 77K among vascular plants of diverse origins. Planta 170: 489-504.
references: Dawes CJ. 1998. Biomass and photosynthetic responses to irradiance by a shallow and a deep water population of Thalassia testudinum on the West coast of Florida. Bulletin of Marine Science 62: 89-96.
references: Dawes CJ, Tomasko DA. 1988. Depth distribution of Thalassia testudinum in two meadows on the west coast of Florida; a difference in effect of light availability. P.S.Z.N.I. Marine Ecology 9: 123-130.
references: Dennison WC. 1987. Effects of light on seagrass photosynthesis, growth and depth distribution. Aquatic Botany 27: 15-26.
references: Dennison WC. 1990. Chlorophyll content. In: Phillips RC, McRoy CP, eds. Seagrass research methods. Paris, France: UNESCO, 83-86.
references: Dennison WC, Alberte RS. 1982. Photosynthetic responses of Zostera marina L. (eelgrass) to in situ manipulations of light intensity. Oecologia 55: 137-144.
references: Dennison WC, Alberte RS. 1985. Role of daily light period in the depth distribution of Zostera marina L. (eelgrass). Marine Ecology Progress Series 25: 51-61.
references: Dennison WC, Alberte RS. 1986. Photoadaptation and growth of Zostera marina L. (eelgrass) along a depth gradient. Journal of Experimental Marine Biology and Ecology 98: 265-282.
references: Dennison WC, Orth KA, Moore RJ, Stevenson JC, Carter V, Kollar S, Batiuk RA. 1993. Assessing water quality with submersed aquatic vegetation. Bioscience 43: 86-94.
references: Dixon LK, Leverone JR. 1995. Light requirements of Thalassia testudinum in Tampa Bay, Florida. City, FL, USA: South Florida Water Management District. Mote Marine Laboratory Technical Report no. 425. Sarasota, FL, USA.
references: Drew EA. 1978. Factors affecting photosynthesis and its seasonal variation in the seagrasses Cymodocea nodosa (Ucria) Aschers. & Posidonia oceanica (L.) Delile in the Mediterranean. Journal of Experimental Marine Biology and Ecology 31: 173-194.
references: Drew EA. 1979. Physiological aspects of primary production in seagrasses. Aquatic Botany 7: 139-150.
references: Duarte CM. 1991. Seagrass depth limits. Aquatic Botany 40: 363-377.
references: Duarte CM. 2002. The future of seagrass meadows. Environmental Conservation 29: 192-206.
references: Duarte CM, Chiscano CL. 1999. Seagrass biomass and production: a reassessment. Aquatic Botany 65: 159-174.
references: Duarte CM, Merino M, Gallegos M. 1995. Evidence of iron deficiency in seagrasses growing above carbonate sediments. Limnology and Oceanography 40: 1153-1158.
references: Dubinsky Z, Falkowski PG, Porter JW, Muscatine L. 1984. Absorption and utilization of radiant energy by light- and shade-adapted colonies of the hermatypic coral Stylophora pistillata. Proceedings of the Royal Society of London 222: 203-214.
references: Dubinsky Z, Stambler N, Ben-Zion M, McCloskey LR, Porter JW, Muscatine L, Falkowski PG. 1990. The effect of external nutrient resources on the optical properties and photosynthetic efficiency of Stylophora pistillata. Proceedings of the Royal Society of London 239: 231-246.
references: Dunton KH, Tomasko DA. 1994. In situ photosynthesis in the seagrass Halodule wrightii in a hypersaline subtropical lagoon. Marine Ecology Progress Series 107: 281-293.
references: Enríquez S. 2005. Light absorption efficiency and the package effect in the leaves of the seagrass Thalassia testudinum. Marine Ecology Progress Series 289: 141-150.
references: Enríquez S, Sand-Jensen K. 2003. Variation in light absorption properties of Mentha aquatica L. as a function of leaf form: implications for plant growth. International Journal of Plant Science 164: 125-136.
references: Enríquez S, Agustí S, Duarte CM. 1994. Light absorption by marine macrophytes. Oecologia 98: 121-129.
references: Enríquez S, Marbá N, Duarte CM, Van Tussenbroek BI, Reyes-Zavala G. 2001. Effects of seagrass Thalassia testudinum on sediment redox. Marine Ecology Progress Series 219: 149-158.
references: Enríquez S, Merino M, Iglesias-Prieto R. 2002. Variations in the photosynthetic performance along the leaves of the tropical seagrass Thalassia testudinum. Marine Biology 140: 891-900.
references: Enríquez S, Marbá N, Cebrián J, Duarte CM. 2004. Annual variation in leaf photosynthesis and leaf nutrient content in four Mediterranean seagrasses. Botanica Marina 47: 295-306.
references: Enríquez S, Pantoja-Reyes NI. 2005. Form-function analysis of the effect of canopy morphology on leaf self-shading in the seagrass Thalassia testudinum. Oecologia 145: 235-243.
references: Falkowski PG, Raven JA. 1997. Aquatic photosynthesis. Malden, MA, USA: Blackwell Science.
references: Falkowski PG, Dubinsky Z, Wyman K. 1985. Growth irradiance relationships in phytoplankton. Limnology and Oceanography 30: 311-321.
references: Fourqurean JW, Zieman JC. 1991. Photosynthesis, respiration and whole plant carbon budget of the seagrass Thalassia testudinum. Marine Ecology Progress Series 69: 161-170.
references: Frost-Christensen H, Sand-Jensen K. 1992. The quantum efficiency of photosynthesis in macroalgae and submerged angiosperms. Oecologia 91: 377-384.
references: Govindjee. 1999. On the requirement of minimum of four versus eight quanta of light for the evolution of one molecule of oxygen in photosynthesis: a historical note. Photosynthesis Research 59: 249-254.
references: Herzka SZ, Dunton KH. 1997. Seasonal photosynthetic patterns of the seagrass Thalassia testudinum in the Western Gulf of Mexico. Marine Ecology Progress Series 152: 103-117.
references: Horton P, Ruban AV, Walters RG. 1996. Regulation of light harvesting in green plants. Annual Review of Plant Physiology and Plant Molecular Biology 47: 655-684.
references: Iglesias-Prieto R, Trench RK. 1994. Acclimation and adaptation to irradiance in symbiotic dinoflagellates. I. Responses of the photosynthetic unit to changes in photon flux density. Marine Ecology Progress Series 113: 163-175.
references: Iglesias-Prieto R, Trench RK. 1997. Photoadaptation, photoacclimation and niche diversification in invertebrate-dinoflagellate symbioses. In: Lessios HA, McIntyre IG, eds. Proceedings of the 8th International Coral Reef Symposium, Vol. 2. Balboa, Panama: Smithsonian Tropical Research Institute, 1319-1324.
references: Jiménez C, Niell FX, Alagarra P. 1987. Photosynthetic adaptation of Zostera noltii Hornem. Aquatic Botany 29: 217-226.
references: Kenworthy WJ, Haunert DE. 1991. The light requirements of seagrasses. Proceedings of a workshop to examine the capability of water quality criteria, standards and monitoring programs to protect seagrasses. NOAA Technical Memorandum NMFS-SERC-287.
references: Kirk JTO. 1994. Light and photosynthesis in aquatic ecosystems, 2nd edn. Cambridge, UK: University of Cambridge Press.
references: Lee KS, Dunton KH. 1997. Effects of in situ light reduction on the maintenance, growth and partitioning of carbon resources in Thalassia testudinum Banks ex Konig. Journal of Experimental Marine Biology and Ecology 210: 53-73.
references: Lichtenthaler HK, Wellburn AR. 1983. Determination of total carotenoids and chlorophyll a and b of leaf extracts in different solvents. Biochemical Society Transactions 603: 591-592.
references: Major KM, Dunton KH. 2002. Variations in light-harvesting characteristics of the seagrass, Thalassia testudinum: evidence for photoacclimation. Journal of Experimental Marine Biology and Ecology 275: 173-189.
references: Masini RJ, Cary JL, Simpson CJ, McComb AJ. 1995. Effects of light and temperature on the photosynthesis of temperate meadow-forming seagrasses in Western Australia. Aquatic Botany 49: 239-254.
references: Niyogi K. 1999. Photoprotection revisited: genetic and molecular approaches. Annual Review of Plant Physiology and Plant Molecular Biology 50: 333-359.
references: Olesen B, Enríquez S, Duarte CM, Sand-Jensen K. 2002. Depth-acclimation of photosynthesis, morphology and demography of Posidonia oceanica and Cymodocea nodosa in the Spanish Mediterranean Sea. Marine Ecology Progress Series 236: 89-97.
references: Patriquin DG. 1975. Migration of blowouts in seagrass beds at Barbados and Carriacou, West Indies, and its ecological and geological implications. Aquatic Botany 1: 163-189.
references: Pirc H. 1986. Seasonal aspects of photosynthesis in Posidonia oceanica: influence of depth, temperature and light intensity. Aquatic Botany 26: 203-212.
references: Ramus J. 1990. A form-function analysis of photon capture for seaweeds. Hydrobiologia 204/205: 65-71.
references: Shibata K. 1959. Spectrophotometry of translucence biological materials - opal glass transmission method. Methods of Biochemical Analysis 7: 77-109.
references: Short FT, Wyllie-Echeverría S. 1996. Natural and human induced disturbance of seagrasses. Environmental Conservation 23: 17-27.
references: Sokal RR, Rohlf FJ. 1981. Biometry - the principles and practice of statistics in biological research, 2nd edn. New York, NY, USA: W.H. Freeman.
references: Stapel J, Hemminga MA. 1997. Nutrient re-absorption from seagrass leaves. Marine Biology 128: 197-206.
references: Strickland JDH. 1958. Solar radiation penetrating the ocean. A review of requirements, data and methods of measurement, with particular reference to photosynthetic productivity. Journal of Fisheries Research Board of Canada 15: 453-493.
references: Titlyanov E, Cherbadgy I, Kolmakov P. 1995. Daily variations of primary production and dependence of photosynthesis on irradiance in seaweeds and seagrass Thalassodendron ciliatum of the Seychelles Islands. Photosynthesis 31: 101-115.
references: Tomasko DA, Dawes CJ. 1989. Evidence for the physiological integration between shaded and unshaded short shoots of Thalassia testudinum. Marine Ecology Progress Series 54: 299-305.
references: Tomlinson PB. 1980. Leaf morphology and anatomy in seagrasses. In: Phillips R, McRoy C, eds. Handbook of seagrass biology: an ecosystem perspective. New York, NY, USA: Garland STPM Press, 7-28.
references: Wetzel RL, Penhale PA. 1983. Production ecology of seagrass communities in the lower Chesapeake Bay. Marine Technology Society Journal 17: 22-31.
references: Zieman JC. 1974. Methods for the study of the growth and production of turtlegrass, Thalassia testudinum Konig. Aquaculture 4: 139-143.
references: Zieman JC, Wetzel RG. 1980. Productivity in seagrasses: methods and rates. In: Phillips R, McRoy C, eds. Handbook of seagrass biology: an ecosystem perspective. New York, NY, USA: Garland STPM Press, 87-116.
references: Zimmerman RC, Reguzzoni JL, Alberte RS. 1995. Eelgrass (Zostera marina L.) transplants in San Francisco Bay: role of light availability on metabolism, growth and survival. Aquatic Botany 51: 67-86.