Summary
A brief introduction to the beta-ray gauging technique is given with its application in determining the water content of leaves.
Some aspects for the choice of the radioactive isotope, the detector and the recording system are discussed in respect to their utilization and precision. A short review of the instrumentation used until now is given. The construction of a new beta-ray gauge is described.
Krypton-85 (E max=0.67 mev) with an activity of 0.35 mc served as the radiation source (active diameter=1 mm). This point-shaped and relatively energyrich beta-ray source permits a working distance between source and detector of several centimeters and allows within certain limits a choice of test surface area. A halogen-quenched Geiger-Müller-counter with a window of 2 cm diameter and 1.5–2.0 mg/cm2 was used. In the construction of the measuring set-up special attention was paid to the reproducibility of the geometry between source, sample and detector. The impulses which reach the detector were recorded by an electronic scaler-timer-system.
Count rate measurements were taken at various distances between emitter, absorber and detector. Furthermore the dependence of beta-ray absorption on the nature of the sample was examined. Comparative measurements were made with homogeneous materials (aluminium foils, plastic sheets and filter paper) and heterogeneous materials (leaves with varying anatomical structure). Large differences were found between the amounts of beta-radiation absorbed by the same weights per unit area of these materials. These differences are discussed.
A calibration method is described which allows an accurate determination of the dependence of count rate on water content of the tested leaf area after the experiment. A difference in weight per unit surface area of 0.1 mg/cm2 can be exactly determined.
Leaves of the same species were examined under natural conditions in the habitat of the plants. With these continuous measurements of beta-radiation absorption great daily fluctuations in leaf water content were found according to the special weather conditions.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
Literatur
Barrs, H. D., Weatherley, P. E.: Are-examination of the relative turgidity technique for estimating water deficits in leaves. Aust. J. biol. Sci. 15, 413–428 (1962).
Bielorai, H.: Beta-ray gauging technique for measuring leaf water content changes of Citrus seedlings as affected by the moisture status in the soil. J. exp. Bot. 19, 489–495 (1968).
Böhm, H.: Zählen oder Messen? In: Graul, E. H., Fortschritte der angewandten Radioisotopie und Grenzgebiete, Bd. I, S. 36–53. Heidelberg: Hüthig 1957.
Bornkamm, R.: Standortsbedingungen und Wasserhaushalt von Trespen-Halbtrockenrasen (Mesobromion) im oberen Leinegebiet. Flora (Jena) 146, 23–67 (1958).
Ehrler, W. L., Nakayama, F. S., Bavel, C. H. M. van: Cyclic changes in water balance and transpiration of cotton leaves in a steady environment. Physiol. Plantarum (Cph.) 18, 766–775 (1965).
—, Bavel, C. H. M., van, Nakayama, F. S.: Transpiration, water absorption, and internal water balance of cotton plants as affected by light and changes in saturation deficit. Plant Physiol. 41, 71–74 (1966).
Gardner, W. R., Nieman, R. H.: Lower limit of water availability to plants. Science 143, 1460–1462 (1964).
Gleason, G. I., Taylor, J. D., Tabern, D. L.: Absolute beta counting at defined geometries. Nucleonics 8(5), 12–21 (1951).
Glocker, R., Macherauch, E.: Röntgen- und Kernphysik für Mediziner und Biophysiker. Stuttgart: Thieme 1965.
Jarvis, P. G., Slatyer, R. O.: A controlled-environment chamber for studies of gas exchange by each surface of a leaf. Australia, CSIRO, Div. Land Res. Tech. Paper 29, 1–16 (1966a).
——: Calibration of β gauges for determining leaf water status. Science 153, 78–79 (1966b).
Kramer, P. J., Brix, H.: Measurement of water stress in plants. UNESCO. Aride Zone Res., Proc. Montpellier-Symp., p. 343–351 (1965).
Lange, O. L., Koch, W., Schulze, E. D.: CO2-Gaswechsel und Wasserhaushalt von Pflanzen in der Negev-Wüste am Ende der Trockenzeit. Ber. dtsch. bot. Ges. 82, 39–61 (1969).
Mederski, H. J.: Determination of internal water status of plants by beta ray gauging. Soil Sci. 92, 143–146 (1961).
—: Beta ray gauge senses plant's water stress. Ohio Farm Home Res. 48, 4 (1963).
—: Plant water balance determination by beta gauging technique. Agron. Abstr. 56, 126 (1963); zit. nach Barrs, H. D. In: Kozlowski, T. T., Water deficits and plant growth, vol. I. New York-London: Academic Press 1968.
—, Alles, W.: Beta gauging leaf water status: Influence of changing leaf characteristics. Plant Physiol. 43, 470–472 (1968).
Nakayama, F. S., Ehrler, W. L.: Beta ray gauging technique for measuring leaf water content changes and moisture status of plants. Plant Physiol. 39, 95–98 (1964).
Noy-Meir, I., Ginsburg, B. Z.: An analysis of the water potential isotherm in plant tissue, I. The theory. Aust. J. biol. Sci. 20, 695–721 (1967).
Raschke, K.: Die Reaktionen des CO2-Regelsystems in den Schließzellen von Zea mays auf weißes Licht. Planta (Berl.) 68, 111–140 (1966).
Rolston, D. E., Horton, M. L.: Two beta sources compared for evaluating water status of plants. Agron. J. 60, 333–336 (1968).
Schmeiser, K.: Allgemeiner Nachweis radioaktiver Isotope. In: Schwiegk, H., Turba, F.: Künstliche radioaktive Isotope in Physiologie, Diagnostik und Therapie, Bd. I, S. 1–118, Berlin-Göttingen-Heidelberg: Springer 1961
Seelmann-Eggebert, W., Pfennig, G.: Radionuklid-Tabellen. Herausgeber: Bundesministerium für wissenchaftliche Forschung (1964).
Siri, W. E.: Beta particles. In: Isotopic tracers and nuclear radiations, p. 49–69. New York-Toronto-London: McGraw-Hill 1949.
Skidmore, E. L., Stone, J. F.: Physiological role in regulating transpiration rate of the cotton plant. Agron. J. 56, 405–410 (1964).
Stocker, O.: Die photosynthetischen Leistungen der Steppen- und Wüstenpflanzen. In: Handbuch d. Pflanzenphysiol., Bd. V/2, S. 460–491. Berlin-Göttingen-Heidelberg: Springer 1960.
Weatherley, P. E.: Studies in the water relations of the cotton plant, I. The field measurement of water deficits in leaves. New Phytol. 49, 81–97 (1950).
— Slatyer, R. O.: Relationship between relative turgidity and diffusion pressure deficit in leaves. Nature (Lond.) 179, 1085–1086 (1957).
Whiteman, P. C., Wilson, G. L.: Estimation of diffusion pressure deficit by correlation with relative turgidity and beta-radiation absorption. Aust. J. biol. Sci. 16, 140–146 (1963).
Wilson, J. W.: The components of leaf water potential, III. Effects of tissue characteristics and relative water content on water potential. Aust. J. biol. Sci. 20, 359–367 (1967).
Yamada, Y., Tamai, S., Miyaguchi, T.: The measurement of the thickness of leaves using S35. Proc. 2nd Japan. Conf. on Radioisotopes, 1958 (U.S. AEC-tr-44 82), p. 1692 (1961), zit. nach: Barrs, H. D. In: Kozlowski, T. T., Water deficits and plant growth, vol. I. New York-London: Academic Press 1968.
Yang, S. J., de Jong, E.: Measurement of internal water stress in wheat plants. Canad. J. Plant Sci. 48, 89–95 (1968).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Buschbom, U. Zur Methodik kontinuierlicher Wassergehalt-Bestimmungen an Blättern mittels β-strahlenabsorption. Planta 95, 146–166 (1970). https://doi.org/10.1007/BF00387247
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00387247