Clones of dwarf-precocious cashew submitted to salt stress and the accumulation of potassium and sodium

Abstract

The objective of this work was to characterize contrast in the pattern of uptake and partitioning of potassium ions (K⁺) and sodium (Na⁺) among roots and leaves of three dwarf cashew genotypes exposed to different NaCl levels. Dwarf cashew seedlings, clones CCP 06, CPC 09 and CAPI 9 at eight leaves stage, were grown in nutrient solution containing 100, 200, 300 and 400 mM NaCl and the dose control during 48 hours under controlled conditions – a growth chamber (25 ± 2 °C, photoperiod 12 h and light intensity 240 μmol m^-2 s^-1). The accumulation of K⁺ and Na⁺ was similar in the roots of the three clones evaluated. The K⁺ content was reduced in the roots and the Na⁺ content increased in function of the doses of NaCl. In leaves, the clones showed little difference in the accumulation of Na⁺ and K⁺. The clones CCP 09 and CPC 06 restricted with greater efficiency the Na⁺ accumulation in leaves, especially until the 200 mM NaCl doses, compared to CAPI 9 genotype. The clone CCP 09 showed highest K⁺/Na⁺ ratio in leaves which might be a favorable characteristic of resistance against the excess of Na⁺ in soils.