Department of Plant Science, University of Western Ontario, London, Ontario N6A 5B7 Canada.
Plant Physiol. 1992 Jul;99(3):1141-5. doi: 10.1104/pp.99.3.1141.
Room temperature chlorophyll a fluorescence was used to determine the effects of developmental history, developmental stage, and leaf age on susceptibility of spinach to in vivo low temperature (5 degrees C) induced photoinhibition. Spinach (Spinacia oleracea cv Savoy) leaves expanded at cold hardening temperatures (5 degrees C day/night), an irradiance of 250 micromoles per square meter per second of photosynthetic proton flux density, and a photoperiod of 16 hours were less sensitive than leaves expanded at nonhardening temperatures (16 or 25 degrees C day/night) and the same irradiance and photoperiod. This differential sensitivity to low-temperature photoinhibition was observed at high (1200) but not lower (500 or 800 micromoles per square meter per second) irradiance treatment. In spite of a differential sensitivity to photoinhibition, both cold-hardened and nonhardened spinach exhibited similar recovery kinetics at either 20 or 5 degrees C. Shifting plants grown at 16 degrees C (day/night) to 5 degrees C (day/night) for 12 days after full leaf expansion did not alter the sensitivity to photoinhibition at 5 degrees C. Conversely, shifting plants grown at 5 degrees C (day/night) to 16 degrees C (day/night) for 12 days produced a sensitivity to photoinhibition at 5 degrees C similar to control plants grown at 16 degrees C. Thus, any resistance to low-temperature photoinhibition acquired during growth at 5 degrees C was lost in 12 days at 16 degrees C. We conclude that leaf developmental history, developmental stage, and leaf age contribute significantly to the in vivo photoinhibitory response of spinach. Thus, these characteristics must be defined clearly in studies of plant susceptibility to photoinhibition.
室温叶绿素荧光被用来确定发育史、发育阶段和叶片年龄对菠菜体内低温（5°C）诱导光抑制敏感性的影响。在冷驯化温度（5°C 日/夜）、光合质子流密度 250 微摩尔/平方米/秒的辐照度和 16 小时光周期下展开的菠菜（Spinacia oleracea cv Savoy）叶片比在非驯化温度（16 或 25°C 日/夜）和相同辐照度和光周期下展开的叶片更不敏感。这种对低温光抑制的敏感性差异在高光（1200）下观察到，但在较低光（500 或 800 微摩尔/平方米/秒）下观察不到。尽管对光抑制的敏感性不同，但冷驯化和非冷驯化的菠菜在 20°C 或 5°C 时均表现出相似的恢复动力学。在完全展开叶片后，将在 16°C（日/夜）下生长的植物转移到 5°C（日/夜）12 天，不会改变在 5°C 下对光抑制的敏感性。相反，将在 5°C（日/夜）下生长的植物转移到 16°C（日/夜）12 天，会使在 5°C 下对光抑制的敏感性类似于在 16°C 下生长的对照植物。因此，在 5°C 下生长时获得的任何对低温光抑制的抗性在 16°C 下 12 天后都会丧失。我们得出结论，叶片发育史、发育阶段和叶片年龄对菠菜体内光抑制反应有显著影响。因此，在研究植物对光抑制的敏感性时，必须明确这些特征。
