Hu W H, Shi K, Song X S, Xia X J, Zhou Y H, Yu J Q
Department of Horticulture, Huajiachi Campus, Zhejiang University, Kaixuan Road 268, Hangzhou 310029, China.
Plant Physiol Biochem. 2006 Nov-Dec;44(11-12):837-43. doi: 10.1016/j.plaphy.2006.10.016. Epub 2006 Oct 27.
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.
分别研究了低温对黄瓜（Cucumis sativus L.）叶片和根系呼吸作用（抗SHAM、细胞色素途径和抗KCN、交替途径）、温度敏感性、相对电解质电导率以及氧化应激程度（H₂O₂和丙二醛（MDA）含量）的影响。在8℃低温处理4天后，根系总呼吸和抗KCN呼吸在不同测量温度下均增加。相比之下，抗SHAM呼吸保持不变。相比之下，低温显著降低了叶片总呼吸，且这种降低主要归因于抗SHAM呼吸的下降。低温明显降低了抗KCN呼吸对温度变化的敏感性。低温处理的叶片和根系中泛醌库的还原水平（UQr/UQt）均升高，而丙酮酸含量仅在低温处理的根系中增加，在低温处理的叶片中未增加。此外，叶片中H₂O₂和MDA含量的增加幅度远大于根系。组织离子渗漏也呈现相同趋势。综合来看，结果表明根系较高的耐冷性与其较高的总呼吸和抗KCN呼吸有关。
