Plant Physiology Unit, CSIRO Division of Food Research and School of Biological Sciences, Macquarie University, North Ryde, N.S.W. 2113, Australia.
Plant Physiol. 1977 Apr;59(4):623-7. doi: 10.1104/pp.59.4.623.
Mitochondrial oxidative activity and membrane lipid structure of two wheat (Triticum aestivum L.) cultivars were measured as a function of temperature. The Arrhenius activation energy for the oxidation of both succinate and alpha-ketoglutarate was constant over the temperature range of 3 to 27 C. The activation energy for succinate-cytochrome c oxidoreductase activity was also constant over the same temperature range. The concentration of mitochondria in the reaction, the degree of initial inhibition of state 3 respiration, and the time after isolation of mitochondria were each shown to be capable of causing a disproportionate decrease in the rate of oxidation at low temperatures which resulted in an apparent increase in the activation energy of oxidative activity. Using three spin-labeling techniques, wheat membrane lipids were shown to undergo phase changes at about 0 C and 30 C. It is concluded that the membrane lipids of wheat, a chillingresistant plant, undergo a phase transition similar to the transition observed in the membrane lipids of chilling-sensitive plants. For wheat, however, the transition is initiated at a lower temperature and extends over a wider temperature range.
作为温度的函数，我们测量了两种小麦（Triticum aestivum L.）品种的线粒体氧化活性和膜脂结构。琥珀酸和α-酮戊二酸氧化的 Arrhenius 活化能在 3 至 27°C 的温度范围内保持恒定。琥珀酸-细胞色素 c 氧化还原酶活性的活化能在相同的温度范围内也保持恒定。反应中线粒体的浓度、状态 3 呼吸初始抑制的程度以及线粒体分离后的时间都被证明能够导致低温下氧化速率不成比例地降低，从而导致氧化活性的活化能表观增加。使用三种自旋标记技术，表明小麦膜脂在约 0°C 和 30°C 时发生相转变。结论是，耐寒植物小麦的膜脂发生类似于在对冷敏感植物的膜脂中观察到的相转变。然而，对于小麦，该转变在较低的温度下开始，并在较宽的温度范围内扩展。
