A comparison of the water relations characteristics of Helianthus annuus and Helianthus petiolaris when subjected to water deficits

M. A. Sobrado, Neil C. Turner

Research output: Contribution to journalArticle

43 Citations (Scopus)

Abstract

The effect of water deficits on the water relations and stomatal responses of Helianthus annuus and Helianthus petiolaris were compared in plants growing in the glasshouse under controlled conditions. Unirrigated plants of both genotypes were subjected to two different stress rates in which predawn leaf water potentials declined steadily at either 0.15 MPa day-1 or 0.50 MPa day-1. In both genotypes water stress induced a gradual and similar decrease in leaf conductance from 1.6 to 0.3 cm s-1 as water potential decreased from-0.5 to-2.0 MPa. The relationship between leaf conductance and leaf water potential was not affected by the rate of stress development. Development of predawn leaf water potentials of-1.3 MPa had no significant effect on the relative water content at zero turgor, the apoplastic water content or the volumetric elastic modulus of whole leaves in either species, but decreased the osmotic potential at full turgor and zero turgor by 0.22 MPa and decreased the turgid weight: dry weight ratio from 10.6 to 8.4 in H. annuus, but not in H. petiolaris. In H. annuus leaves expanded during stress development, changes in the osmotic potential at full turgor induced by water deficits did not disappear on rewatering.

Original languageEnglish
Pages (from-to)309-313
Number of pages5
JournalOecologia
Volume58
Issue number3
DOIs
Publication statusPublished - Jun 1983
Externally publishedYes

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