Effect of salinity stress on physiological aspects of pumpkin (Cucurbita moschata Duchesne. ‘Laikaotok’) under hydroponic condition

Abstract

Pumpkin ( Cucurbita moschata ) ‘Laikaotok’ is an important edible vegetable but growth and crop yield are affected by salinity stress. Response of physiological traits to salinity stress was investigated under hydroponic culture using Hoagland's solution at different NaCl concentrations of 0, 15, 30, 45, 60 and 120 mM. All treatments were cultured for four weeks and physiological traits were recorded. Results showed that pumpkin growth decreased after NaCl treatment, especially at 45 mM and higher concentrations. Leaf number, leaf width, leaf length, root number, stem length, stem diameter, SPAD unit, chlorophyll fluorescence in dark condition for 30 min (Fv'/Fm'), chlorophyll fluorescence in light condition (Fv/Fm), total chlorophyll, chlorophyll a and chlorophyll b contents significantly decreased (p < 0.05). Results indicated that salt concentration at less than 45 mM NaCl was suitable for C. moschata ‘Laikaotok’ growth. Phenotypic correlation coefficient estimation of 12 physiological traits showed positive correlation at a highly significant level, except for the correlation between plant height - Fv/Fm; plant height - Fv'/Fm'; root number - Fv/Fm and root number - Fv'/Fm'. This is the first report on salt stress response in C. moschata ‘Laikaotok’. Knowledge gained will be useful for pumpkin culture or rootstock selection under sensitive and moderately sensitive saline conditions.