Histo-anatomical leaf variations related to depth in Posidonia oceanica
Silvia Nicastro A , Anna M. Innocenti A and Nicodemo G. Passalacqua A BA Museo di Storia Naturale della Calabria ed Orto Botanico, Università della Calabria, 87030 Arcavacata di Rende (Cosenza), Italy.
B Corresponding author. Email: nicodemo.passalacqua@unical.it
Functional Plant Biology 42(4) 418-422 https://doi.org/10.1071/FP14111
Submitted: 8 April 2014 Accepted: 13 January 2015 Published: 12 February 2015
Abstract
The purpose of our study is to explore the acclimation of Neptune seagrass (Posidonia oceanica (L.) Delile) to depth by characterising the histo-anatomical leaf modifications. P. oceanica is the dominant seagrass and main habitat constructor of seagrass meadows in the Mediterranean Sea. Meadows play an important biological and ecological role in marine ecosystems, serving as a habitat for a large diversity of species and an efficient erosion protection system for our coasts. Seagrasses are very sensitive to change in light availability and small changes can have significant effects on growth, abundance and distribution. In this study, we analyse changes in P. oceanica leaves collected at –5 m, –15 m and –25 m depth in the Cirella meadow (Tyrrhenian coast, Southern Italy) in order to determine their depth-related histo-anatomical variation. Two main changes were observed at depth: (1) photosynthetic epidermal cells showed smaller chloroplasts but in the same number; and (2) leaves showed smaller epidermal cells and in greater number. Hence, the photosynthetic surface of P. oceanica leaves remains the same at different depths but pigment absorption efficiency can be significantly enhanced with depth. This response supports the differential photoacclimatory response of seagrasses with respect to terrestrial plants previously documented. Mesophyll cells are smaller with depth and more numerous, with a consequent increase in leaf density. The number of vascular bundles also increases, which allows improved functional efficiency of the transport system and solute exchange. Our study is a new contribution to the morpho-functional implications of the histo-anatomy of P. oceanica.
Additional keywords: depth acclimation, light availability, Neptune seagrass, photosynthesis.
References
Bay D (1984) A field study of the growth dynamics and productivity of Posidonia oceanica (L.) Delile in Calvi Bay, Corsica. Aquatic Botany 20, 43–64.| A field study of the growth dynamics and productivity of Posidonia oceanica (L.) Delile in Calvi Bay, Corsica.Crossref | GoogleScholarGoogle Scholar |
Björkman O (1981) Responses to different quantum flux densities. In ‘Physiological plant ecology I. Responses to the physical environment. Encyclopedia of plant physiology 12A’. (Eds OL Lange, PS Nobel, CB Osmond, H Ziegler). pp. 57–107. (Springer-Verlag: Berlin)
Boudouresque CF, Bernard G, Bonhomme P, Charbonnel E, Diviacco G, Meinesz A, Pergent G, Pergent-Martini C, Ruitton S, Tunesi L (2006) ‘Préservation et conservation des herbiers à Posidonia oceanica.’ (RaMoGe Publication: Monaco)
Bricaud A, Morel A (1986) Light attenuation and scattering by phytoplanktonic cells: a theoretical modeling. Applied Optics 25, 571–580.
| Light attenuation and scattering by phytoplanktonic cells: a theoretical modeling.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD1c%2FnsVWqsQ%3D%3D&md5=e30a8e7bad8e434776fb622c6de34cb9CAS | 18231215PubMed |
Bulthuis DA, Woelkerling WJ (1983) Biomass accumulation and shading effects of epiphytes on leaves of the seagrass, Heterozostera tasmanica, in Victoria, Australia. Aquatic Botany 16, 137–148.
| Biomass accumulation and shading effects of epiphytes on leaves of the seagrass, Heterozostera tasmanica, in Victoria, Australia.Crossref | GoogleScholarGoogle Scholar |
Cayabyab NM, Enríquez S (2007) Leaf photoacclimatory responses of the tropical seagrass Thalassia testudinum under mesocosm conditions: a mechanistic scaling-up study. New Phytologist 176, 108–123.
| Leaf photoacclimatory responses of the tropical seagrass Thalassia testudinum under mesocosm conditions: a mechanistic scaling-up study.Crossref | GoogleScholarGoogle Scholar | 17696981PubMed |
Colombo PM, Rascio N, Cinelli F (1983) Posidonia oceanica (L.) Delile: a structural study of the photosynthetic apparatus. Marine Ecology (Berlin) 4, 133–145.
| Posidonia oceanica (L.) Delile: a structural study of the photosynthetic apparatus.Crossref | GoogleScholarGoogle Scholar |
Dennison WC (1987) Effects of light on seagrass photosynthesis, growth and depth distribution. Aquatic Botany 27, 15–26.
| Effects of light on seagrass photosynthesis, growth and depth distribution.Crossref | GoogleScholarGoogle Scholar |
Duarte CM (1991) Seagrass depth limits. Aquatic Botany 40, 363–377.
| Seagrass depth limits.Crossref | GoogleScholarGoogle Scholar |
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.
| Light absorption efficiency and the package effect in the leaves of the seagrass Thalassia testudinum.Crossref | GoogleScholarGoogle Scholar |
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, 234–242.
| Form–function analysis of the effect of canopy morphology on leaf self-shading in the seagrass Thalassia testudinum.Crossref | GoogleScholarGoogle Scholar |
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 Sciences 164, 125–136.
| Variation in light absorption properties of Mentha aquatica L. as a function of leaf form: implications for plant growth.Crossref | GoogleScholarGoogle Scholar |
Enríquez S, Agustí S, Duarte CM (1992) Light absorption by seagrass Posidonia oceanica leaves. Marine Ecology Progress Series 86, 201–204.
| Light absorption by seagrass Posidonia oceanica leaves.Crossref | GoogleScholarGoogle Scholar |
Enríquez S, Agustí S, Duarte CM (1994) Light absorption by marine macrophytes. Oecologia 98, 121–129.
| Light absorption by marine macrophytes.Crossref | GoogleScholarGoogle Scholar |
Enríquez S, Merino M, Iglesias-Prieto R (2002) Variation in the photosynthetic performance along the leaves of the tropical seagrass Thalassia testudinum. Marine Biology 140, 891–900.
| Variation in the photosynthetic performance along the leaves of the tropical seagrass Thalassia testudinum.Crossref | GoogleScholarGoogle Scholar |
Hammer Ø, Harper DAT, Ryan PD (2001) Past: paleontological statistics software package for education and data analysis. Palaeontologia Electronica 4, 9
Hedley J, Enríquez S (2010) Optical properties of canopies of the tropical seagrass Thalassia testudinum estimated by a three-dimensional radiative transfer model. Limnology and Oceanography 55, 1537–1550.
| Optical properties of canopies of the tropical seagrass Thalassia testudinum estimated by a three-dimensional radiative transfer model.Crossref | GoogleScholarGoogle Scholar |
Kirk JTO (1994) ‘Light and photosynthesis in aquatic ecosystems.’ 2nd edn. (Cambridge University Press: Cambridge, UK)
Markanger S, Sand-Jensen K (1994) The physiology and ecology of light–growth relationship in macroalgae. Progress in Phycological Research 10, 209–298.
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.
| Depth-acclimation of photosynthesis, morphology and demography of Posidonia oceanica and Cymodocea nodosa in the Spanish Mediterranean Sea.Crossref | GoogleScholarGoogle Scholar |
Ramus J (1990) A form–function analysis of photon capture for seaweeds. Hydrobiologia 204/205, 65–71.
Terashima I, Saeki T (1983) Light environment within a leaf. I. Optical properties of paradermal sections of Camellia leaves with special reference to differences in the optical properties of palisade and spongy tissues. Plant & Cell Physiology 24, 1493–1501.
Tomilson PB (1980) Leaf morphology and anatomy in seagrasses. In ‘Handbook of seagrass biology: an ecosystem perspective’. (Eds R Phillips, C McRoy) pp. 7–28. (Garland Press: New York)
Tomilson PB (1982) ‘Anatomy of the monocotyledons. VII. Helobiae (Alismatidae).’ (Clarendon Press: Oxford, UK)
Vogelmann TC, Martin G (1993) The functional significance of palisade tissue: penetration of directional versus diffuse light. Plant, Cell & Environment 16, 65–72.
| The functional significance of palisade tissue: penetration of directional versus diffuse light.Crossref | GoogleScholarGoogle Scholar |
Zimmerman R (2003) A biotopical model of irradiance distribution and photosynthesis in seagrass canopies. Limnology and Oceanography 48, 568–585.
| A biotopical model of irradiance distribution and photosynthesis in seagrass canopies.Crossref | GoogleScholarGoogle Scholar |
