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The responses of stomata and leaf gas exchange to vapour pressure deficits and soil water content : II. In the mesophytic herbaceous species Helianthus annuus

Titelangaben

Turner, Neil C. ; Schulze, Ernst-Detlef ; Gollan, Thomas:
The responses of stomata and leaf gas exchange to vapour pressure deficits and soil water content : II. In the mesophytic herbaceous species Helianthus annuus.
In: Oecologia. Bd. 65 (August 1985) Heft 3 . - S. 348-355.
ISSN 1432-1939
DOI: https://doi.org/10.1007/BF00378908

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Projektfinanzierung: Deutsche Forschungsgemeinschaft

Abstract

The responses of leaf water potential, leaf conductance, transpiration rate and net photosynthetic rate to vapour pressure deficits varying from 10 to 30 Pa kPa-1 were followed in Helianthus annuus as the extractable soil water decreased. With a vapour pressure deficit of 25 Pa kPa-1 around the entire plant as the soil water content decreased, the leaf conductance and transpiration rate showed a strong closing response to leaf water potential at a value of-0.65 MPa, whereas with a vapour pressure deficit of 10 Pa kPa-1 around the entire plant, the rate of transpiration and leaf conductance decreased almost linearly as the leaf water potential decreased from-0.4 to-1.0 MPa. Increasing the vapour pressure deficit from 10 to 30 Pa kPa-1 in 5 Pa kPa-1 steps decreased the leaf conductance by a similar proportion at all extractable soil water contents. At high soil water contents, the decrease in conductance with leaf water potential was greater when the vapour pressure deficit was increased than when it was not, indicating a direct influence of vapour pressure deficit on the stomata. The rate of net photosynthesis decreased to a smaller degree than the leaf conductance when the vapour pressure deficit around the leaf was varied. Overall, the net photosynthetic rate decreased almost linearly from 20 to 25 μmol m-2 s-1 at-0.3 MPa to 5 μmol m-2 s-1 at-1.2 MPa. As the soil water decreased, the internal carbon dioxide partial pressure was maintained between 14 and 25 Pa.

No unique relationship between leaf conductance, transpiration rate or photosynthetic rate and leaf water potential was observed, but in all experiments leaf conductance and the rate of net photosynthesis decreased when about two-thirds of the extractable water in the solid had been utilized irrespective of the leaf water potential. We conclude that soil water status, not leaf water status, affects the stomatal behaviour and photosynthesis of H. annuus.

Weitere Angaben

Publikationsform: Artikel in einer Zeitschrift
Begutachteter Beitrag: Ja
Zusätzliche Informationen: BayCEER13384
Institutionen der Universität: Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Biologie > Lehrstuhl Pflanzenökologie
Forschungseinrichtungen > Sonderforschungsbereiche, Forschergruppen > SFB 137 Gesetzmäßigkeiten und Strategien des Stoffumsatzes in ökologischen Systemen
Fakultäten
Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften
Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Biologie
Forschungseinrichtungen
Forschungseinrichtungen > Sonderforschungsbereiche, Forschergruppen
Titel an der UBT entstanden: Ja
Themengebiete aus DDC: 500 Naturwissenschaften und Mathematik > 580 Pflanzen (Botanik)
Eingestellt am: 19 Mai 2015 09:41
Letzte Änderung: 15 Mär 2016 13:37
URI: https://eref.uni-bayreuth.de/id/eprint/13886