Effects of chilling on respiration and induction of cyanide-resistant respiration in seedling roots of cucumber.

摘要

The effects of chilling stress on respiration and induction of the alternative pathway (AP) were investigated with roots of 3-day-old cucumber cv. Encore seedlings grown at 26degree C and then chilled at 2, 10 or 15 deg C for 24, 48, 96, 144 or 192 h. Oxygenuptake by roots exposed to 2degree C was significantly lower than that by 10 or 15degree C-treated roots, and the inhibition of oxygen uptake in the presence of SHAM (salicylhydroxamic acid) increased from 29% in unchilled tissue to 60% after 96 h of treatment. At 10and 15degree C, the capacity of the AP was nearly double that of the unchilled control and the 2degree C-treated seedlings. A 24-h, postchilling treatment at 26degree C resulted in greater oxygen uptake at all temperatures as treatment time increased up to 96 h. At 2degree C, the capacity of the AP was significantly reduced below the level of the 10 and 15degree C-treated tissue and the untreated control. The AP became fully activated by 96 h in roots chilled at 2degree C. Results suggest that the capacity of the AP can be affected by low-temperature treatments, and exposure to 2degree C for up to 96 h leads to a significant loss in AP capacity.