title: Disentangling the contributions of osmotic and ionic effects of salinity on stomatal, mesophyll, biochemical and light limitations to photosynthesis.
abstract: There are conflicting opinions on the relative importance of photosynthetic limitations under salinity. Quantitative limitation analysis of photosynthesis provides insight into the contributions of different photosynthetic limitations, but it has only been applied under saturating light conditions. Using experimental data and modelling approaches, we examined the influence of light intensity on photosynthetic limitations and quantified the osmotic and ionic effects of salinity on stomatal (LS ), mesophyll (LM ), biochemical (LB ) and light (LL ) limitations in cucumber (Cucumis sativus L.) under different light intensities. Non-linear dependencies of LS , LM and LL to light intensity were found. Osmotic effects on LS and LM increased with the salt concentration in the nutrient solution (Ss ) and the magnitude of LM depended on light intensity. LS increased with the Na(+) concentration in the leaf water (Sl ) and its magnitude depended on Ss . Biochemical capacity declined linearly with Sl but, surprisingly, the relationship between LB and Sl was influenced by Ss . Our results suggest that (1) improvement of stomatal regulation under ionic stress would be the most effective way to alleviate salinity stress in cucumber and (2) osmotic stress may alleviate the ionic effects on LB but aggravate the ionic effects on LS .
authors.affiliation: Institute of Horticultural Production Systems, Leibniz Universität Hannover, Hannover, 30419, Germany.
authors.forename: Tsu-Wei
authors.initials: TW
authors.lastname: Chen
authors.affiliation: Department of Vegetable Crops, Geisenheim University, Geisenheim, 65366, Germany.
authors.forename: Katrin
authors.initials: K
authors.lastname: Kahlen
authors.affiliation: Institute of Horticultural Production Systems, Leibniz Universität Hannover, Hannover, 30419, Germany.
authors.forename: Hartmut
authors.initials: H
authors.lastname: Stützel
mesh_terms: D007477:Ions; D008027:Light; D058503:Mesophyll Cells / Q000502:physiology* / Q000528:radiation effects; D009995:Osmosis / Q000528:radiation effects; D010788:Photosynthesis / Q000528:radiation effects*; D054046:Plant Stomata / Q000502:physiology* / Q000528:radiation effects; D054712:Salinity; D013312:Stress, Physiological / Q000528:radiation effects
chemical_list: D007477:Ions
keywords: Cucumis sativus; FvCB model; ionic stress; light condition; osmotic stress; quantitative limitation analysis