Influence of a night temperature drop on the growth and cold tolerance of cucumber plants.

摘要

Every day for 6 days, we lowered the night temperature to 12deg C for 1, 2, 3, 4, 6, or 12 h at the beginning, in the middle, or at the end of the nocturnal period and studied the effects of these treatments on the dry-matter accumulation, the leaf petiole length, and the cold tolerance of cucumber (Cucumis sativus) plants. Average day temperature was 20deg C. The length of leaf petioles decreased in all treatments. A 2- to 3-h-long temperature drop caused a decline in dry-matter accumulation and the greatest increase in the cold tolerance, whereas a 4- to 6-h-long chilling increased plant dry weight and somewhat reduced their cold tolerance. A 12-h-long temperature decrease significantly diminished both the dry-weight accumulation and the cold tolerance. Daily chilling treatments during the nocturnal period resulted in a three-phase stress response.