Abstract
Dissolved O2 concentration in hydroponics was controlled at 0.01, 0.10 and 0.20 mM, and the growth of cucumber plant was analyzed in the respective dissolved O2 concentrations at a root temperature of 25°C, an air temperature of 25°C, a relative humidity of 70% and a PPFD of 300 μmol m-2 s-1 (a photoperiod of 12 h) . Growth of leaves and roots was inhibited at lower dissolved O2 concentrations, while the nodal development was not affected. At the lowest dissolved O2 concentration of 0.01 mM, remarkable inhibition of leaf expansion was found with the decreased leaf water content. These facts suggest that leaf expansion was inhibited through leaf turgor loss caused by the depressed water uptake of roots in O2-deficient nutrient solution.
