Differential growth of Spartina densiflora populations under saline flooding is related to adventitious root formation and innate root ion regulation

GRIMOLDI AA; PLOSCHUK EL; DI BELLA CE; ESCARAY FJ; ROSSI LOPARDO MS; STRIKER GG

FUNCTIONAL PLANT BIOLOGY

CSIRO PUBLISHING

Lugar: Collingwood; Año: 2016 vol. 43 p. 52 - 61

1445-4408

Global change anticipates scenarios of sea level rise that would provoke long lasting floods, especially in lowland areas of salt marshes. We aimed at evaluating the morpho-physiological adjustment ability to deal with continuous saline flooding of Spartina densiflora plants from lowlands and uplands along a subtle topographical gradient (0.2 m differential altitude). Plants from both origins were subjected to continuous saline flooding (300 mM NaCl) for 35 days. Responses associated to adventitious rooting, aerenchyma formation, concentration of Na+, K+ and Cl- in roots and shoots tissues, tillering and growth were assessed. Root responses differentiated populations given that lowland plants showed higher ability for root adventitious formation and innate superior root ion regulation than upland plants. High constitutive K+ concentration plus high Na+ exclusion in root tissues led to significant low values of Na+/K+ ratios in lowland plants. Better root functioning was, in turn, related with  more consistent shoot performance as lowland plants maintained plant tiller number and shoot relative growth rate unaltered while upland plants decreased both parameters by 35% and 18%, respectively, when in saline flooding. The superior performance of lowland plants indicates that locally adapted populations can be promoted in salt marsh habitats with subtle differences at topographic level.