Effects of Adding NaCl and Reducing Aeration to Nutrient Culture Solution on the Growth of Cucumber Fruit

Abstract

Effects of NaCl addition and reduced aeration to nutrient solution on the growth of cucumber (Cucumis sativus L. cv. Asomidori No. 5) fruit were studied. NaCl was added to nutrient solution when plants had about 10 expanded leaves; the aeration treatment was started 2 days later.
The relative growth rate (RGR) by fruit volume was not affected by aeration frequency at 0 mM NaCl. In the spring experiment, RGR at 60 mM NaCl decreased markedly when the solution was aerated infrequently (dissolved oxygen concentration (DO) being 1 to 2.5 mg liter^-1), whereas RGR at 60 mM NaCl approximated that at 0 mM NaCl when the solution was aerated continuously (DO being 5 to 7.5 mg liter^-1). The effect of NaCl at 60 mM in combination with reduced aeration on RGR in the autumn experiment was less marked than that in the spring experiment.
DO was suggested to be one of the environmental factors involved in the seasonal dif- ference in the growth of cucumber as influenced by 60 mM NaCl (Tazuke, 1997).