Summary
The effects of leaf hairs (pubescence) on leaf spectral characteristics were measured for the drought-deciduous desert shrub Encelia farinosa. Leaf absorptance to solar radiation is diminished by the presence of pubescence. The pubescence appears to be reflective only after the hairs have dried out. There are seasonal changes in leaf absorptance; leaves produced at the beginning of a growing season have high absorptances, whereas leaves produced during the growing season are more pubescent and have lower absorptances. The decrease in leaf absorptance is the result of an increase in pubescence density and thickness. Between 400 and 700 nm (visible wavelengths), pubescence serves as a blanket reflector. However, over the entire solar spectrum (400–3000 nm), the pubescence preferentially reflects near infrared radiation (700–3000 nm) over photosynthetically useful solar radiation (400–700 nm). Leaf absorptance to solar radiation (400–3000 nm) varies between 46 and 16%, depending on pubescence; whereas leaf absorptance to photosynthetically useful radiation (400–700 nm) may vary from 81 to 29%.
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References
Billings, W.D., Morris, R.J.: Reflection of visible and infrared radiation from leaves of different ecological groups. Am. J. Bot. 38, 327–331 (1951)
Birkebak, R., Birkebak R.: Solar radiation characteristics of tree leaves. Ecology 45, 646–649 (1964)
Björkman, O.: Comparative studies on photosynthesis in higher plants. In: Photophysiology, Vol. 8, pp. 1–63 New York: Academic Press 1973
Bowers, S.A., Hanks, R.J.: Reflection of radiant energy from soils. Soil Sci. 100, 130–138 (1965)
Bowers, S.A., Hayden, C.W.: A simple portable reflectometer for field use. Agron. J. 59, 490–492 (1967)
Clausen, J.D., Keck, D., Hiesey, W.M.: Experimental studies on the nature of species. I. The effect of varied environments of western North American plants. Carnegie Inst. Washington Publ. 520 (1940)
Coulter, J.D., Barnes, C.R., Cowles, H.C.: A text book of botany for Colleges and Universities, Vol. II. Ecology. New York: Amer. Book 1911
Cunningham, G.L., Strain, B.R.: An ecological singificance of seasonal leaf variability in a desert shrub. Ecology 50, 400–408 (1969)
Ehleringer, J., Björkman, O., Mooney, H.A.: Leaf pubescence: effects on absorptance and photosynthesis in a desert shrub. Science 192, 376–377 (1976)
Gates, D.M., Keegan, H.J., Schleter, J.C., Weidner, V.R.: Spectral properties of plants. Appl. Optics 4, 11–20 (1965)
Gausman, H.W., Cardenas, R.: Effects of leaf pubescence of Gynura aurantiaca on light reflectance. Bot. Gaz. 130, 158–162 (1969)
Gausman, H.W., Cardenas, R.: Light reflectance by leaflets of pubescent, normal, and glabrous soybean lines. Agron. J. 65, 837–838 (1973)
Gausman, H.W., Rodriguez, R.R., Escobar, D.E.: Ultraviolet radiation reflectance, transmittance, and absorption by plant leaf epidermises. Agron. J. 67, 720–724 (1975)
MacDougal, D.T.: Botanical features of North American deserts. Carnegie Inst. Washington Publ. 99 (1908)
Moss, R.A., Loomis, W.E.: Absorption spectra of leaves. I. The visible spectrum. Plant Physiol. 27, 370–391 (1952)
Oppenheimer, H.R.: Adaptation to drought: xerophytism. In: Plant-water relationships in arid and semi-arid conditions, pp. 105–138. Paris: UNESCO 1960
Orshan, G., Zand, G.: Seasonal body reduction of certain desert half shrubs. Bull. Res. Counc. Israel Sec. D. Bot. 110, 35–42 (1962)
Pearman, G.I.: The reflection of visible radiation from leaves of some western Australian species. Aust. J. Biol. Sci. 19, 97–103 (1966)
Rabideau, G.S., French, C.S., Holt, A.S.: The absorption and reflection spectra of leaves, chloroplast suspensions, and chloroplast fragments as measured in an Ulbricht sphere. Am. J. Bot. 33, 769–777 (1946)
Ross, J.: Radiative transfer in plant communities. In: Vegetation and atmosphere, Vol. 1, pp. 13–55. London: Academic Press, 1975
Schimper, A.F.W.: Plant geography upon a physiological basis. Oxford: Clarendon 1903
Sellers, W.D., Hill, R.H.: Arizona Climate 1931–1972. Tucson: Univ. of Arizona 1974
Sheilds, L.M.: Leaf xeromorphy as related to physiological and structural influences. Bot. Rev. 16, 399–447 (1950)
Shreve, E.B.: Factors governing seasonal changes in transpiration of Encelia farinosa. Bot. Gaz. 77, 432–439 (1924)
Shreve, F., Wiggins, I.L.: Vegetation and flora of the Sonoran Desert. Stanford: Stanford University Press 1964
Shull, C.A.: A spectrophotometric study of reflection of light from leaf surfaces. Bot. Gaz. 87, 583–607 (1929)
Sinclair, R., Thomas, D.A.: Optical properties of leaves of some species in arid South Australia. Aust. J. Bot. 18, 261–273 (1970)
Walter, H.: Die Hydratur der Pflanze. Jena: Fischer 1931
Warming, E.: Oecology of plants: an introduction to the study of plant communities. London: Oxford University Press 1909
Wong, C.L., Blevin, W.F.: Infrared reflectances of plant leaves. Aust. J. Biol. Sci. 20, 501–508 (1967)
Wooley, J.T.: Water relations of soybean leaf hairs. Agron. J. 56, 569–571 (1964)
Wuenscher, J.E.: The effect of leaf hairs of Verbascum thapsus on leaf energy exchange. New Phytol. 69, 65–73 (1970)
Zohary, M.: On hydro-ecological relations of the Near East degetation. In: Plant-water relationships in arid and semi-arid conditions, pp. 199–212. Paris: UNESCO 1961
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C.I.W.-D.P.B. Publication No. 612
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Ehleringer, J.R., Björkman, O. Pubescence and leaf spectral characteristics in a desert shrub, Encelia farinosa . Oecologia 36, 151–162 (1978). https://doi.org/10.1007/BF00349805
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DOI: https://doi.org/10.1007/BF00349805