Response to salinity in the homoploid hybrid species Helianthus paradoxus and its progenitors H. annuus and H. petiolaris
Article first published online: 27 MAR 2006
Volume 170, Issue 3, pages 615–629, May 2006
How to Cite
Karrenberg, S., Edelist, C., Lexer, C. and Rieseberg, L. (2006), Response to salinity in the homoploid hybrid species Helianthus paradoxus and its progenitors H. annuus and H. petiolaris. New Phytologist, 170: 615–629. doi: 10.1111/j.1469-8137.2006.01687.x
- Issue published online: 29 MAR 2006
- Article first published online: 27 MAR 2006
- Received: 15 December 2005 Accepted: 11 January 2006
- hybrid speciation;
- ion compartmentation;
- salt tolerance;
- Helianthus (sunflower)
- • To contribute to the understanding of ecological differentiation in speciation, we compared salinity responses of the halophytic diploid hybrid species Helianthus paradoxus and its glycophytic progenitors Helianthus annuus and Helianthus petiolaris.
- • Plants of three populations of each species were subjected to a control (nonsaline) and three salinity treatments, including one simulating the ion composition in the habitat of H. paradoxus.
- • Relative to the control, saline treatments led to a 17% biomass increase in H. paradoxus while its progenitors suffered 19–33% productivity reductions and only in H. paradoxus, leaf contents of potassium, calcium, and magnesium were strongly reduced. Under all treatments, H. paradoxus allocated more resources to roots, was more succulent, and had higher leaf contents of sodium (> 200 mmol l−1 tissue water) and sulfur than its progenitor species.
- • These results suggest that salt tolerance and thus speciation of H. paradoxus is related to sodium replacing potassium, calcium and magnesium as vacuolar osmotica. The evolutionary and genetic mechanisms likely to be involved are discussed.