Effect of Root Temperature on the Rate of Water and Nutrient Absorption in Cucumber Cultivars and Figleaf Gourd

Abstract

A comparative study was made of the effect of root temperature on water and nutrient absorption in cucumber (Cucumis sativus L.) cultivars and figleaf gourd (Cucurbita ficifolia Bouchè). These plants were preincubated at root temperatures of 12, 14, 17, 20 and 30°C for 1 or 5 days, then the rate of water and nutrient absorption was determined for the following 24 hours at the each same root temperature.
In cucumber cultivars, absorption of both water and nutrients was greatly inhibited at temperatures lower than 17 or 20°C, depending on nutrient elements. Absorption of nutrients was more severely inhibited than that of water, particularly when the plants were preincubated at lower temperatures for 5 days. The difference in rates between cultivars was relatively insignificant except for P absorption, which was more significantly inhibited at 12_??_17°C in a chilling sensitive summer cultivar ‘Suyo’ than in a less sensitive spring one ‘Kurume-ochiai H’.
In figleaf gourd, which is more tolerant of chilling temperatures than cucumber, both water and nutrients were absorbed at similar rates at all temperatures, being irrespective of preincubation periods. P absorption was exceptionally inhibited at 12°C after 1 day preincubation, but it became unaffected after 5 days preincubation.