Articles
DIURNAL THERMOPERIODISM OF THE CUCUMBER
Plants were treated from planting (5 leaf stage) to the beginning of harvesting (0,5 kg fruit per plant).
In the range 10° (night) to 28° C (day) the plants showed no specific reaction to the day/night temperature amplitude.
Thus, the response of the plants to the temperature conditions can be described by the 24 hour mean temperature.
This includes a reduction of the temperature during the night (CHALLA-TOKI effect). This statement signifies that, in the range tested, the temperature can be controlled to minimize energy consumption.
In the intermediate and warm season this can be achieved by a higher day/night amplitude than generally recommended, since water condensation and guttation are tolerated or prevented.
Moreover, these findings support the hypothesis that fuel can be saved by controlling the night temperature to compensate day temperature for an economical 24 hour mean temperature.
Higher night than day temperature (23/27° C day/night) led to a slower length growth of the stem, but the period from planting to leaf area index 1 was only slightly affected and the period to the beginning of harvest was not affected.
Thus, it seems worthwhile to test the reactions to high night and lower day temperatures in combination with thermal screens during the cold season.