Summary
Measurements of transpiration, leaf water content, and flux of water in a cotton plant exhibiting sustained oscillations, in stomatal conductance are presented, and a model of the mechanism causing this behaviour is developed. The dynamic elements, of the model are capacitors—representing the change of water content with water potential in mesophyll, subsidiary and guard cells—interconnected by resistances representing flow paths in the plant. Increase of water potential in guard cells causes an increase in stomatal conductance. Increase of water potential in the subsidiary cells has the opposite effect and provides the positive feed-back which can cause stomatal conductance to oscillate. The oscillations are shown to have many of the characteristics of free-running oscillations in real plants. The behaviour of the model has been examined, using an analogue computer, with constraints and perturbations representing some of those which could be applied to real plants in physiological experiments. Aspects of behaviour which have been simulated are (a) opening and closing of stomata under the influence of changes in illumination, (b) transient responses due to step changes in potential transpiration, root permeability and potential of water surrounding the roots, (c) the influence of these factors on the occurrence and shape of spontaneous oscillations, and (d) modulation of sustained oscillations due to a circadian rhythm in the permeability of roots.
Similar content being viewed by others
References
Andersson, N. E., Hertz, C. H., Rufelt, H.: A new fast recording hygrometer for plant transpiration measurements. Physiol. Plantarum (Cph.) 7, 753–767 (1954).
Apel, P.: Über rhythmisch verlaufende Änderungen in der CO2-Aufnahme von Blättern. Ber. dtsch. bot. Ges. 80, 3–9 (1967).
Aubert, B., Čatský, J.: The onset of photosynthetic CO2 influx in banana leaf segments as related to stomatal diffusion resistance at different air humidities. Photosynthetica 4, 254–256 (1970).
Barrs, H. D.: Cyclic variations in stomatal aperture, transpiration, and leaf water potential under constant environmental conditions. Ann. Rev. Plant Physiol. 22, 223–236 (1971).
Barrs, H. D., Klepper, B.: Cyclic variations in plant properties under constant environmental conditions. Physiol. Plantarum (Cph.) 21, 711–730 (1968).
Boyer, J. S.: Resistances to water transport in soybean, bean and sunflower. Crop. Sci. 11, 403–407 (1971).
Collins, J. C.: Factors affecting osmotic potential: Plants. In: Respiration and circulation, p. 721–724, Altman, P. L., Dittmer, D. S., eds. Bethesda, Md.: Fed. Amer. Soc. Exp. Biol. 1971.
Cowan, I. R.: An electrical analogue of evaporation from, and flow of water in plants. Planta (Berl.) 106, 221–226 (1972).
Cowan, I. R., Milthorpe, F. L.: Permeability to water: Plant structures. In: Respiration and circulation, p. 705–709, Altman, P. L., Dittmer, D. S., eds. Bethesda, Md.: Fed. Amer. Soc. Exp. Biol. 1971.
Cowan, I. R., Troughton, J. H.: The relative role of stomata in transpiration and assimilation. Planta (Berl.) 97, 325–336 (1971).
Cox, E. F.: Cyclic changes in transpiration of sunflower leaves in a steady environment. J. exp. Bot. 19, 167–175 (1968).
Darwin, F.: Observations on stomata. Phil. Trans. B 190, 531–621 (1898).
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).
Florell, C., Rufelt, H.: Transpiration of wheat plants cultivated under different environmental conditions. Physiol. Plantarum (Cph.) 13, 482–486 (1960).
Gradmann, H.: Untersuchungen über die Wasserverhältnisse des Bodens als Grundlage des Pflanzenwachstums. Jahrb. wiss. Bot. 69, 1–100 (1928).
Harris, D. G.: Water vapour diffusion resistance of transpiring cotton plants as influenced by measured parameters of the environment. Doct. dissert., Univ. of Georgia, Athens (1968).
Heath, O. V. S.: An experimental investigation of the mechanism of stomatal movement, with some preliminary observations on the response of guard cells to shock. New Phytologist 37, 385–395 (1938).
Honert, T. H. van den: Water transport in plants as a catenary process. Disc. Faraday Soc. 3, 146–153 (1948).
Hopmans, P. A. M.: Types of stomatal cycling and their water relations in bean leaves. Z. Pflanzenphysiol. 60, 242–254 (1969).
Hopmans, P. A. M.: Rhythms in stomatal opening of bean leaves. Meded. Landbouwhoogeschool Wageningen 71, No 3 (1971).
Howe, G. F.: Time course of photosynthetic rhythms in Phaseolus vulgaris L. as related to changes in degree of stomatal opening. Ohio J. Sci. 64, 378–384 (1964).
Hsiao, T. C., Acevedo, E., Henderson, D. W.: Maize leaf elongation: continuous measurements and close dependence on plant water status. Science 168, 590–591 (1970).
Humble, G. D., Raschke, K.: Stomatal opening quantitatively related to potassium transport. Evidence from electron probe analysis. Plant. Physiol 48, 447–453 (1971).
Jensen, R. D., Taylor, S. A., Wiebe, H. H.: Negative transport and resistance to flow through plants. Plant Physiol. 36, 633–638 (1961).
Kanemasu, E. T., Tanner, C. B.: Stomatal diffusion resistance of snap beans. II. Effects of light. Plant Physiol. 44, 1542–1546 (1969).
Karmanov, V. G., Meleshchenko, S. N., Savin, V. N.: Character of change in impedance of the plant leaf with an auto-oscillatory mode of water metabolism. Biofizika 10, 155–160 (1965).
Karmanov, V. G., Meleshchenko S. N., Savin, V. N.: Study of the dynamics of the water metabolism of the plant and construction of an electrical analogue of the system of water exchange. Biofizika 11, 147–155 (1966).
Karmanov, V. G., Savin, V. N.: On the auto-oscillatory nature of water metabolism. Dokl. Akad. Nauk SSSR 154, 16–19 (1964).
Kriedemann, P. E.: Photosynthesis and transpiration as a function of gaseous diffusive resistance in orange leaves. Physiol. Plantarum (Cph.) 24, 218–225 (1971).
Kuiper, P. J. C.: The effects of environmental factors on the transpiration of leaves, with special reference to stomatal light response. Meded. Landbouwhoogeschool Wageningen 61, No 7 (1961).
Lang, A. R. G., Klepper, B., Cumming, M. J.: Leaf water balance during oscillation of stomatal aperture. Plant. Physiol. 44, 826–830 (1969).
Meister, A., Apel, P.: Ein Modell für die Funktion der Schließzellenbewegungen. Studia Biophys. 11, 125–130 (1968).
Meleshchenko, S. N., Karmanov, V. G.: Mathematical model of the water metabolism of the plant with reference to the mechanism of positive feedback. Biofizika 11, 731–733 (1966).
Milthorpe, F. L., Penman, H. L.: The diffusive conductivity of wheat leaves. J. exp. Bot. 18, 422–457 (1967).
Milthorpe, F. L., Spencer, E. J.: Experimental studies of the factors controlling transpiration. III. The interrelations between transpiration rate, stomatal movement, and leaf water content. J. exp. Bot. 8, 413–437 (1957).
Philip, J. R.: The osmotic cell, solute diffusibility, and the plant water economy. Plant Physiol. 33, 264–271 (1958a).
Philip, J. R.: Propagation of turgor and other properties through cell aggregations. Plant Physiol. 33, 271–274 (1958b).
Philip, J. R.: Plant water relations: some physical aspects. Ann. Rev. Plant Physiol. 17, 245–268 (1966).
Raschke, K.: Zur Steuerung der Transpiration durch die Photosynthese. Ber. dtsch. bot. Ges. 80, 138–144 (1967).
Raschke, K.: Stomatal responses to pressure changes and interruptions in the water supply of detached leaves of Zea mays L. Plant Physiol. 45, 415–423 (1970).
Scarth, G. W., Loewy, A., Shaw, M.: Use of the infrared total absorption method for estimating the time course of photosynthesis and transpiration. Canad. J. Res. 26, 94–107 (1948).
Skidmore, E. L., Stone, J. F.: Physiological role in regulating transpiration rate of the cotton plant. Agron. J. 56, 405–410 (1964).
Stålfelt, M. G.: Pulsierende Blattgewebe. Planta (Berl.) 7, 720–734 (1929a).
Stålfelt, M. G.: Die Abhängigkeit der Spaltöffnungsreaktion von der Wasserbilanz. Planta (Berl.) 8, 287–340 (1929b).
Stålfelt, M. G.: Die stomatäre Transpiration und die Physiologie der Spaltöffnungen. In: Handbuch der Pflanzenphysiologie, Bd.III, S. 351–426. Berlin-Göttingen-Heidelberg: Springer 1956.
Teoh, C. T., Palmer, J. H.: Nonsynchronized oscillations, in stomatal resistance among sclerophylls of Eucalyptus umbra. Plant Physiol. 47, 409–411 (1971).
Troughton, J. H.: Plant water status and carbon dioxide exchange of cotton leaves. Aust. J. biol. Sci. 22, 289–302 (1969).
Troughton, J. H., Cowan, I. R.: Carbon dioxide exchange in cotton: some anomalous fluctuations. Science 161, 281–283 (1968).
Weatherley, P. E.: Some aspects of water relations. In: Advances in botanical research, vol. 3, p. 171–206 Preston, R. D., ed. London-New York: Acad. Press 1970.
Went, F. W.: Plant growth under controlled conditions. III. Correlation between various physiological processes and growth in the tomato plant. Amer. J. Bot. 31, 597–618 (1944).
Woo, K. B., Boersma, L., Stone, L. N.: Dynamic simulation model of the transpiration process. Water Resources Res. 2, 85–97 (1966).
Woo, K. B., Stone, L. N., Boersma, L.: A conceptual model of stomatal control mechanisms. Water Resources Res. 2, 71–84 (1966).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Cowan, I.R. Oscillations in stomatal conductance and plant functioning associated with stomatal conductance: Observations and a model. Planta 106, 185–219 (1972). https://doi.org/10.1007/BF00388098
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00388098