Summary
Although not often discrete, the canopy (i.e., the organization of branches, shoot systems and their extent) remains the most definable and useful unit of function in bryophytes. Chambers used for gas exchange provide an integrated summary of canopy photosynthetic function. However, other techniques can provide more information on spatial variation in physiological process in both the horizontal and vertical planes. Three examples of such studies are presented here. First, variation in photosystem II (PSII) function has been evaluated, along a canopy surface, using an imaging chlorophyll fluorometer. We evaluated the quantum yield of PSII, ϕPSII, and calculated the relative rate of photosynthetic electron transport (RETR) on 7 cm diameter samples of ten Sphagnum species during drying. Spatial variation in RETR increased both during drying as well as in high light, which led to different relationships between mean RETR and its variation—across light gradients, the relationship was positive, but negative when RETR was reduced by tissue desiccation. Studies of photosynthetic function using chlorophyll fluorescence measurements need to match their sampling protocols to account for this difference. Further, combining a laser scanning approach that provides three-dimensional information on canopy structure with functional imaging allows assessment of function in three dimensions (3D) within the canopy. This is illustrated using a thermal imaging camera to measure temperature distribution within Pleurozium schreberi canopies under still conditions and with wind. This imaging system resolved 9 °C temperature differences within the canopy and localized shoot temperature relative to canopy height. Finally, computational canopy (i.e., virtual) models have been developed for bryophyte canopies, particularly ones with simple branching structure. A model of this type is shown here for the liverwort Bazzania trilobata and a light model implemented using a ray tracing algorithm. Output from this model followed the attenuation of light predicted by the Lambert-Beer Law and such a technique can be used to evaluate how branching architecture and density affect the dynamics of light capture in bryophytes. New approaches based on novel imaging technologies are in rapid development and present opportunities to further our understanding of function within bryophyte canopies.
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Abbreviations
- Chl –:
-
Chlorophyll;
- ETR –:
-
Rate of photosynthetic electron transport as calculated from chlorophyll a fluorescence measurements;
- F0 :
-
– Baseline fluorescence in dark-adapted tissue;
- F0’:
-
– Baseline fluorescence in light-adapted tissue;
- Fm :
-
– Maximum chlorophyll a fluorescence in dark-adapted tissue at saturating light;
- Fv/Fm :
-
– Ratio of variable (=Fm − Fo) to maximal fluorescence in dark-adapted tissue;
- Fv’/Fm’:
-
– Ratio of variable to maximal fluorescence in light-adapted tissue;
- I0 :
-
– Intensity of incident light at top of canopy;
- Ix :
-
– Intensity of incident light at depth x within canopy;
- K:
-
– Light extinction coefficient;
- Kapp :
-
– Apparent light extinction coefficient, product of K and SAIx;
- PPFD:
-
– Photosynthetic photon flux density;
- PRI:
-
– Photochemical reflectance index;
- Q10 :
-
– Temperature coefficient;
- RETR:
-
– Relative rate of (calculated) photosynthetic electron transport;
- SAIx :
-
– Shoot area index above depth x within canopy;
- ϕPSII :
-
– Quantum yield of photosynthesis as calculated from chlorophyll a fluorescence parameters
References
Abramoff MD, Magalhaes PJ, Ram SJ (2004) Image processing with image. J Biophotonics Int 11:36–42
Aldea M, Frank TD, DeLucia EH (2006) A method for quantitative analysis of spatially variable physiological processes across leaf surfaces. Photosynth Res 90:161–172
Baker NR (2008) Chlorophyll fluorescence: a probe of photosynthesis in vivo. Annu Rev Plant Biol 59:89–113
Chaerle L, Leinonen I, Jones HG, Van Der Straeten D (2007) Monitoring and screening plant populations with combined thermal and chlorophyll fluorescence imaging. J Exp Bot 58:773–784
Chelle M, Andrieu B (1998) The nested radiosity model for the distribution of light within plant canopies. Ecol Model 111:75–91
Davey MC, Ellis-Evans JC (1996) The influence of water content on the light climate within Antarctic mosses characterized using an optical microprobe. J Bryol 19:235–242
Davey MC, Rothery P (1997) Interspecific variation in respiratory and photosynthetic parameters in Antarctic bryophytes. New Phytol 137:231–240
Gamon JA, Serrano L, Surfus JS (1997) The photochemical reflectance index: an optical indicator of photosynthetic radiation use efficiency across species, functional types, and nutrient level. Oecologia 112:492–501
Gerdol R, Bonora A, Poli F (1994) The vertical pattern of pigment concentrations in chloroplasts of Sphagnum capillifolium. Bryologist 97:158–161
Govindjee (2004) Chlorophyll a fluorescence: a bit of basics and history. In: Papageorgiou GC, Govindjee (eds) Chlorophyll a fluorescence: a signature of photosynthesis, vol 19, Advances in photosynthesis and respiration. Springer, Dordrecht, pp 1–42
Graham EA, Hamilton MP, Mishler BD, Rundel PW, Hansen MH (2006) Use of a networked digital camera to estimate net CO2 uptake of a desiccation-tolerant moss. Int J Plant Sci 167:751–758
Harris A (2008) Spectral reflectance and photosynthetic properties of Sphagnum mosses exposed to progressive drought. Ecohydrology 1:35–42
Hayward PM, Clymo RS (1982) Profiles of water content and pore size in Sphagnum and peat, and their relation to peat bog ecology. Proc Roy Soc Lond B Biol 215:299–325
Leinonen I, Jones HG (2004) Combining thermal and visible imagery for estimating canopy temperature and identifying plant stress. J Exp Bot 55:1423–1431
Lovelock CE, Robinson SA (2002) Surface reflectance properties of Antarctic moss and their relationship to plant species, pigment composition, and photosynthetic function. Plant Cell Environ 25:1239–1250
Maxwell K, Johnson GN (2000) Chlorophyll fluorescence—a practical guide. J Exp Bot 51:659–668
Morison JIL, Lawson T (2007) Does lateral gas diffusion in leaves matter? Plant Cell Environ 30:1072–1085
Ollinger SV (2011) Sources of variability in canopy reflectance and the convergent properties of plants. New Phytol 189:375–394
Oxborough K (2004) Using chlorophyll a fluorescence imaging to monitor photosynthetic performance. In: Papageorgiou GC, Govindjee (eds) Chlorophyll a fluorescence: a signature of photosynthesis, vol 19, Advances in photosynthesis and respiration. Springer, Dordrecht, pp 409–428
Papageorgiou GC, Govindjee (eds) (2004) Chlorophyll a fluorescence: a signature of photosynthesis, vol 19, Advances in photosynthesis and respiration. Springer, Dordrecht, 818 pages
Papageorgiou GC, Govindjee (2011) Photosystem II fluorescence: slow changes – scaling from the past. J Photochem Photobiol B Biol 104:258–270
Pradal C, Dufour-Kowalski S, Boudon F, Fournier C, Godin C (2008) OpenAlea: a visual programming and component-based software platform for plant modeling. Funct Plant Biol 25:751–760
Prusinkiewicz P (2000) Simulation modeling of plants and plant ecosystems. Commun ACM 43:84–93
Prusinkiewicz P, Lindenmayer A (1990) The algorithmic beauty of plants. Springer, New York
Rice SK (2012) The cost of capillary integration for bryophyte canopy water and carbon dynamics. Lindbergia 35:53–62
Rice SK, Gutman C, Krouglicof N (2005) Laser scanning reveals bryophyte canopy structure. New Phytol 166:695–704
Rice SK, Aclander L, Hanson DT (2008) Do bryophyte shoot systems function like vascular plant leaves or canopies? Functional trait relationships in Sphagnum mosses (Sphagnaceae). Am J Bot 95:1366–1374
Rice SK, Neal N, Mango J, Black K (2011a) Modeling bryophyte productivity across gradients of water availability using canopy form-function relationships. In: Tuba Z, Slack NG, Stark LR (eds) Bryophyte ecology and global change. Cambridge University Press, Cambridge, pp 441–457
Rice SK, Neal N, Mango J, Black K (2011b) Relationships among shoot tissue, canopy and photosynthetic characteristics in the feathermoss Pleurozium schreberi. Bryologist 114:367–378
Rolfe SA, Scholes JD (2010) Chlorophyll fluorescence imaging of plant-pathogen interactions. Protoplasma 247:163–175
Soler C, Sillion F, Blaise F, Dereffye P (2003) An efficient instantiation algorithm for simulating radiant energy transfer in plant models. ACM T Graphic 22:204–233
Thévenaz P, Ruttimann UE, Unser M (1998) A pyramid approach to subpixel registration based on intensity. IEEE T Image Process 7:27–41
Tobias M, Niinemets Ü (2010) Acclimation of photosynthetic characteristics of the moss Pleurozium schreberi to among-habitat and within-canopy light gradients. Plant Biol 12:743–754
Uchida M, Muraoka H, Nakatsubo T, Bekku Y, Ueno T, Kanda H, Koizumi H (2002) Net photosynthesis, respiration, and production of the moss Sanionia uncinata on a glacier foreland in the high Arctic, Ny-Ålesund, Svalbard. Arct Antarct Alp Res 34:287–292
Van der Hoeven EC, Huynen CIJ, During HJ (1993) Vertical profiles of biomass, light intercepting area and light intensity in chalk grassland mosses. J Hattori Bot Lab 74:261–270
Zona D, Oechel WC, Richards JH, Hastings S, Kopetz I, Ikawa H, Oberbauer S (2011) Light-stress avoidance mechanisms in a Sphagnum-dominated wet coastal Arctic tundra ecosystem in Alaska. Ecology 92:633–644
Zotz G, Kahler H (2007) A moss “canopy” – Small-scale differences in microclimate and physiological traits in Tortula ruralis. Flora 202:661–666
Acknowledgements
The authors thank James Ross for conducting preliminary studies using 3D thermography, Mark Hooker, Kristina Streignitz for technical assistance. SKR thanks the Union College for sabbatical leave that facilitated writing of this chapter.
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Rice, S.K., Hanson, D.T., Portman, Z. (2014). Structural and Functional Analyses of Bryophyte Canopies. In: Hanson, D., Rice, S. (eds) Photosynthesis in Bryophytes and Early Land Plants. Advances in Photosynthesis and Respiration, vol 37. Springer, Dordrecht. https://doi.org/10.1007/978-94-007-6988-5_10
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