Physiological alterations modulated by rootstock and scion combination in cashew under salinity

In this study we evaluated the influence of rootstocks and scions on physiological disturbances that are induced by salinity in cashew (Anacardium occidentale) plantlets. Two cashew genotypes, CCP 09 and BRS 226, were utilized as rootstocks and scions, resulting in four scion/rootstock combinations by reciprocal grafting. The plantlets were irrigated in absence (control) or in presence of 50 or 200 mM NaCl for 15 days under greenhouse conditions. The plantlets with BRS 226 as rootstocks demonstrated higher transpiration and greater accumulations of Na⁺ and Cl⁻, proline and free amino acids in leaves compared to plantlets that having CCP 09 as rootstocks. The K⁺ content in roots and leaves of all four combinations was not influenced by salinity or by different scion/rootstock combinations. The self-grafting of the BRS 226 genotype showed the highest stability for chlorophyll and Rubisco, exhibiting the highest tolerance to salinity. The scion genotype did not affect any of the studied physiological parameters. The studied physiological disturbances induced by salinity in cashew plantlets were more influenced by rootstock than by scion and these changes were also dependent on compatibility between scion and rootstock.