Counter-anions Influence Greenhouse Rose (Rosa ×hybrida) Responses to Sodium-based Salinity

Abstract

<jats:p>Greenhouse rose plants, `Bull's Eye', budded on the rootstocks <jats:italic>Rosa manetti</jats:italic> and <jats:italic>R.</jats:italic> × `Natal Briar', were grown in containers filled with a peat-based growing medium. The plants were irrigated with a 0.5× Hoagland solution salinized with a fixed 12-mM Na solution made up of seven ratios of NaCl, Na<jats:sub>2</jats:sub>SO<jats:sub>4</jats:sub>, and NaNO<jats:sub>3</jats:sub> (100:0, 50:50:0, 0:100:0, 0:50:50, 0:0:100, 50:0:50, and 33:33:33). The results after four flushes of growth and flowering showed higher dry weight productivities in <jats:italic>R. manetti</jats:italic> plants. Salt composition (i.e., counter-anion ratios) significantly affected the dry weight yield of `Natal Briar' plants, with those irrigated with 100% Na<jats:sub>2</jats:sub>SO<jats:sub>4</jats:sub> and NaNO<jats:sub>3</jats:sub> having the highest and lowest values, respectively. While the plants budded on <jats:italic>R. manetti</jats:italic> did not show significant responses to salt composition, there was a strong tendency for higher dry weight yields in binary salt (anion) compositions. Leachates collected throughout the study showed similar pH (7.5) and electrical conductivities (4.7 dS/m) for all salt treatments. Leachate Cl- concentrations were linearly correlated with Cl- application, whereas leachate Na+ concentrations remained similar among treatments. Plants on <jats:italic>R. manetti</jats:italic> accumulated less leaf Na+ and Cl- than in <jats:italic>R.</jats:italic> × `Natal Briar' plants, with lower values observed, in general, in plants irrigated with solutions containing Na<jats:sub>2</jats:sub>SO<jats:sub>4.</jats:sub></jats:p>