Morpho-physiological response to vertically heterogeneous soil salinity of two glycophyte woody taxa, Salix matsudana x S.alba?NZ 26992? and Eucalyptus camaldulensis Dehnh

QUIÑONES MARTORELLO, A.; GYENGE JE; FERNÁNDEZ ME

PLANT AND SOIL

SPRINGER

Lugar: Berlin; Año: 2017

0032-079X

Aims: Growth and physiology of Salixmatsudana x S. alba and E. camaldulensis were evaluated in verticalsaline gradients to test whether growth is determined by the mean salinity ofrhizosphere, the average salinity weighed by the root number in each portion ofthe soil, the lowest or the highest rhizosphere salinity.Methods: Saplings were grown inpots with an original irrigation system determining upper and lower soil layerswith a combination of 4 treatments: control, moderate homogeneous salinity(Ho), and heterogeneous salinity, with high concentration of NaCl in the upper (HeU)or in the lower soil layer (HeL).Results: E. camaldulensis salinetreatments decreased Ψpre-dawnandΨosmotic. HeU and HeL didnot decrease stem growth (RVG), but HeL reduced root biomass in lower soillayer. Ho treatment reduced RVG (50%), increasing leaf senescence and alteringsome ions concentration (but not Na+). In Salix sp., Ho decreased Ψpre-dawn and chlorophyllcontent, increasing leaf senescence and Cl- concentration resulting in low leafbiomass. HeL also decreased plant total biomass.Conclusions: Lowerconcentration of salt homogeneously distributed in soil profile would have moreeffect than high salt concentration but restricted to one soil layer. Thenegative impact of high salinity would be higher if salts are in deeper than inupper soil layers. Salt tolerance thresholds would then depend more on the saltspatial distribution in the soil than on its average concentration along therhizosphere.