低温胁迫严重威胁作物生产力和经济可持续性。植物通过部署先进的分子机制来感知和响应冷胁迫来应对这种情况。跨膜蛋白启动这些反应,引发一系列涉及钙离子(Ca2+)等第二信使的事件,活性氧(ROS),和肌醇磷酸酯。其中,钙信号是最重要的,激活下游磷酸化级联和冷反应基因的转录,包括冷调节(COR)基因。这篇综述的重点是植物如何通过双重策略来管理冻害:耐寒和避寒。耐受机制涉及对降低温度的适应,培育抗寒性逐步积累。相比之下,避免机制依赖于冷冻保护剂分子,如钾离子(K+),脯氨酸,甘油,和抗冻蛋白(AFP)。冷冻保护剂调节细胞内溶质浓度,降低冰点,抑制冰的形成,并保持质膜的流动性。此外,这些分子表现出抗氧化活性,清除ROS,防止蛋白质变性,并随后减轻细胞损伤。通过与水分子形成广泛的氢键,冷冻保护剂还限制细胞间的水运动,最大限度地减少细胞外冰晶的形成,和细胞脱水。冷冻保护剂的部署是一种关键的适应性策略,可以增强植物对冷胁迫的抵抗力,并促进在冷冻环境中的生存。然而,这些保护作用的具体生理和分子机制仍未被充分理解。因此,这篇综述强调需要进一步研究阐明这些机制,并评估它们对作物生产力和可持续性的潜在影响,促进植物生物学和环境科学的进步话语。
Low temperature stress significantly threatens crop productivity and economic sustainability. Plants counter this by deploying advanced molecular mechanisms to perceive and respond to cold stress. Transmembrane proteins initiate these responses, triggering a series of events involving secondary messengers such as calcium ions (Ca2+), reactive oxygen species (ROS), and inositol phosphates. Of these, calcium signaling is paramount, activating downstream phosphorylation cascades and the transcription of cold-responsive genes, including cold-regulated (COR) genes. This review focuses on how plants manage freeze-induced damage through dual strategies: cold tolerance and cold avoidance. Tolerance mechanisms involve acclimatization to decreasing temperatures, fostering gradual accumulation of cold resistance. In contrast, avoidance mechanisms rely on cryoprotectant molecules like potassium ions (K+), proline, glycerol, and antifreeze proteins (AFPs). Cryoprotectants modulate intracellular solute concentration, lower the freezing point, inhibit ice formation, and preserve plasma membrane fluidity. Additionally, these molecules demonstrate antioxidant activity, scavenging ROS, preventing protein denaturation, and subsequently mitigating cellular damage. By forming extensive hydrogen bonds with water molecules, cryoprotectants also limit intercellular water movement, minimizing extracellular ice crystal formation, and cell dehydration. The deployment of cryoprotectants is a key adaptive strategy that bolsters plant resilience to cold stress and promotes survival in freezing environments. However, the specific physiological and molecular mechanisms underlying these protective effects remain insufficiently understood. Therefore, this review underscores the need for further research to elucidate these mechanisms and assess their potential impact on crop productivity and sustainability, contributing to the progressive discourse in plant biology and environmental science.