Peoples T R, Koch D W, Smith S C
Department of Plant Science, University of New Hampshire, Durham, New Hampshire 03824.
Plant Physiol. 1978 Mar;61(3):472-3. doi: 10.1104/pp.61.3.472.
The photosynthetic responses of four alfalfa (Medicago sativa L.) cultivars to 10 and 22 C air temperatures were examined and the relationship between the photosynthetic response at 10 C and the fatty acid composition of the chloroplast membranes was determined. Chilling-resistant cultivars exhibited moderate reductions in photosynthesis at 10 C, compared to 22 C, and contained a significantly greater percentage of polyunsaturated fatty acids in the chloroplast membrane and a greater double bond index than the chilling-sensitive cultivars. The chilling-sensitive cultivars exhibited severe reductions in photosynthesis at 10 C, compared to 22 C. The reduction in photosynthesis at 10 C is shown to be negatively correlated (r = -0.94) with the double bond index of the chloroplast membranes of the cultivars observed.The results support the hypothesis that reduced photosynthesis due to chilling temperatures is influenced by the unsaturated fatty acid composition of the chloroplast membrane which affect temperature-induced phase changes in chloroplast membrane lipids.
研究了四个苜蓿（紫花苜蓿）品种在10℃和22℃气温下的光合响应，并确定了10℃时的光合响应与叶绿体膜脂肪酸组成之间的关系。与22℃相比，抗寒品种在10℃时光合作用适度降低，叶绿体膜中多不饱和脂肪酸的百分比显著更高，双键指数也比冷敏感品种更高。与22℃相比，冷敏感品种在10℃时光合作用严重降低。观察到品种叶绿体膜的双键指数与10℃时光合作用的降低呈负相关（r = -0.94）。这些结果支持了这样的假设，即低温导致的光合作用降低受叶绿体膜不饱和脂肪酸组成的影响，而叶绿体膜不饱和脂肪酸组成会影响叶绿体膜脂的温度诱导相变。
