title: Different effects of chilling on respiration in leaves and roots of cucumber (Cucumis sativus).
abstract: The effects of chilling on respiration (SHAM-resistant, cytochrome pathway and KCN-resistant, alternative pathway), temperature sensitivity, relative electrolyte conductivity, and degrees of oxidative stress (H(2)O(2) and malonaldehyde (MDA) contents) were separately examined in leaves and roots of cucumber (Cucumis sativus L.). After chilling at 8 degrees C for 4 days, both total respiration and KCN-resistant respiration in roots increased at different measurement temperatures. In contrast, SHAM-resistant respiration remained unchanged. In comparison, chilling significantly decreased the total respiration in leaves and this decrease was mostly due to a decrease in SHAM-resistant respiration. Chilling apparently decreased the sensitivity of KCN-resistant respiration to changes of temperature. The reduction levels of ubiquinone pool (UQr/UQt) increased both in chilled leaves and roots whilst pyruvate content increased only in chilled roots, but not in chilled leaves. Furthermore increases of H(2)O(2) and MDA contents were much greater in leaves than in roots. The same trend was also observed for ion leakage from tissues. Taken together, the results suggested that the higher chilling tolerance of roots was associated with their high total respiration and KCN-resistant respiration.
authors.affiliation: Department of Horticulture, Huajiachi Campus, Zhejiang University, Kaixuan Road 268, Hangzhou 310029, China. jqyu@zju.edu.cn
authors.forename: W H
authors.initials: WH
authors.lastname: Hu
authors.forename: K
authors.initials: K
authors.lastname: Shi
authors.forename: X S
authors.initials: XS
authors.lastname: Song
authors.forename: X J
authors.initials: XJ
authors.lastname: Xia
authors.forename: Y H
authors.initials: YH
authors.lastname: Zhou
authors.forename: J Q
authors.initials: JQ
authors.lastname: Yu
mesh_terms: D003080:Cold Temperature; D018553:Cucumis sativus / Q000378:metabolism*; D004351:Drug Resistance / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000378:metabolism; D008315:Malondialdehyde / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects; D018515:Plant Leaves / Q000378:metabolism*; D018517:Plant Roots / Q000378:metabolism*; D011190:Potassium Cyanide / Q000494:pharmacology; D014451:Ubiquinone / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D014451:Ubiquinone; D008315:Malondialdehyde; D006861:Hydrogen Peroxide; C003741:ubiquinol; D011190:Potassium Cyanide