Plieth C, Hansen U P, Knight H, Knight M R
Department of Plant Sciences, University of Oxford, UK.
Plant J. 1999 Jun;18(5):491-7. doi: 10.1046/j.1365-313x.1999.00471.x.
Cold elicits an immediate rise in the cytosolic free calcium concentration ([Ca2+]c) of plant cells. We have studied the concerted action of the three underlying mechanisms, namely sensing, sensitisation and desensitisation, which become important when plants in the field are subjected to changes in temperature. We applied different regimes of temperature changes with well-defined cooling rates to intact roots of Arabidopsis thaliana expressing the calcium-indicator, aequorin. Our results indicate that temperature sensing is mainly dependent on the cooling rate, dT/dt, whereas the absolute temperature T is of less importance. Arabidopsis roots were found to be sensitive to cooling rates of less than dT/dt = 0.01 degrees C/s. However, at cooling rates below 0.003 degrees C/s (i.e. cooling 10 degrees C in 1 h) there is no detectable [Ca2+]c response at all. At low temperature, the sensitivity of the plant cold-detection system is increased. This in turn produces greater cooling-induced [Ca2+]c elevations. Prolonged or repeated cold treatment attenuates the [Ca2+]c responses to subsequent episodes of cooling.
低温会引起植物细胞胞质游离钙浓度（[Ca2+]c）迅速升高。我们研究了三种潜在机制的协同作用，即感知、致敏和脱敏，当田间植物受到温度变化影响时，这些机制就变得至关重要。我们对表达钙指示剂水母发光蛋白的拟南芥完整根系施加具有明确降温速率的不同温度变化模式。我们的结果表明，温度感知主要取决于降温速率dT/dt，而绝对温度T的重要性较低。发现拟南芥根系对低于dT/dt = 0.01℃/s的降温速率敏感。然而，在低于0.003℃/s的降温速率下（即1小时内降温10℃），根本检测不到[Ca2+]c反应。在低温下，植物冷检测系统的敏感性会增加。这反过来又会使降温诱导的[Ca2+]c升高幅度更大。长时间或重复的冷处理会减弱[Ca2+]c对后续降温事件的反应。
