Planta

, Volume 160, Issue 2, pp 143–150

Transpiration-induced changes in the photosynthetic capacity of leaves

  • Thomas D. Sharkey
Article

DOI: 10.1007/BF00392862

Cite this article as:
Sharkey, T.D. Planta (1984) 160: 143. doi:10.1007/BF00392862

Abstract

High transpiration rates were found to affect the photosynthetic capacity of Xanthium strumarium L. leaves in a manner analagous to that of low soil water potential. The effect was also looked for and found in Gossypium hirsutum L., Agathis robusta (C. Moore ex Muell.) Bailey, Eucalyptus microcarpa Maiden, Larrea divaricata Cav., the wilty flacca tomato mutant (Lycopersicon esculentum (L.) Mill.) and Scrophularia desertorum (Munz) Shaw. Two methods were used to distinguish between effects on stomatal conductance, which can lower assimilation by reducing CO2 availability, and effects on the photosynthetic capacity of the mesophyll. First, the response of assimilation to intercellular CO2 pressure (Ci) was compared under conditions of high and low transpiration. Second, in addition to estimating Ci using the usual Ohm's law analogy, Ci was measured directly using the closed-loop technique of T.D. Sharkey, K. Imai, G.D. Farquhar and I.R. Cowan (1982, Plant Physiol, 60, 657–659). Transpiration stress responses of Xanthium strumarium were compared with soil drought effects. Both stresses reduced photosynthesis at high Ci but not at low Ci; transpiration stress increased the quantum requirement of photosynthesis. Transpiration stress could be induced in small sections of leaves. Total transpiration from the plant did not influence the photosynthetic capacity of a leaf kept under constant conditions, indicating that water deficits develop over small areas within the leaf. The effect of high transpiration on photosynthesis was reversed approximately half-way by returning the plants to low-transpiration conditions. This reversal occurred as fast as measurements could be made (5 min), but little further recovery was observed in subsequent hours.

Key words

Photosynthesis and water stress Transpiration Water stress Xanthium 

Abbreviations and symbols

A

photosynthetic CO2 assimilation rate

Ca

ambient CO2 partial pressure

Ci

partial pressure of CO2 inside the leaf

VPD

leaf-to-air water-vapor pressure difference

Copyright information

© Springer-Verlag 1984

Authors and Affiliations

  • Thomas D. Sharkey
    • 1
  1. 1.Biological Sciences Center, Desert Research InstituteUniversity of Nevada SystemRenoUSA

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