Abstract:
Winter crops acquire frost tolerance during the process of cold acclimation when plants are exposed to low but non-freezing temperatures that is connected to specific metabolic adjustments. Warm breaks during/after cold acclimation disturb the natural process of acclimation, thereby decreasing frost tolerance and can even result in a resumption of growth. This phenomenon is called deacclimation. In the last few years, studies that are devoted to deacclimation have become more important (due to climate changes) and necessary to be able to understand the mechanisms that occur during this phenomenon. In the acclimation of plants to low temperatures, the importance of plant membranes is indisputable; that is why the main aim of our studies was to answer the question of whether (and to what extent) deacclimation alters the physicochemical properties of the plant membranes. The studies were focused on chloroplast membranes from non-acclimated, cold-acclimated and deacclimated cultivars of winter oilseed rape. The analysis of the membranes (formed from chloroplast lipid fractions) using the Langmuir technique revealed that cold acclimation increased membrane fluidity (expressed as the Alim values), while deacclimation generally decreased the values that were induced by cold. Moreover, because the chloroplast membranes were penetrated by lipophilic molecules such as carotenoids or tocopherols, the relationships between the structure of the lipids and the content of these antioxidants in the chloroplast membranes during the process of the cold acclimation and deacclimation of oilseed rape are discussed.
摘要:
当植物暴露于与特定代谢调节有关的低但非冻结温度时,冬季作物在冷驯化过程中获得了抗冻性。冷驯化期间/之后的温暖休息会干扰自然的驯化过程,从而降低霜冻耐受性,甚至可以导致恢复生长。这种现象称为去适应。在过去的几年里,致力于去适应的研究变得更加重要(由于气候变化),并且有必要能够理解在这种现象中发生的机制。在植物适应低温的过程中,植物膜的重要性是无可争议的;这就是为什么我们的研究的主要目的是回答是否(以及在多大程度上)适应改变植物膜的物理化学性质的问题。研究集中在非适应的叶绿体膜上,冷适应和去适应的冬季油菜品种。使用Langmuir技术对膜(由叶绿体脂质部分形成)的分析显示,冷适应增加了膜的流动性(表示为Alim值),而去适应通常会降低寒冷引起的值。此外,因为叶绿体膜被亲脂性分子如类胡萝卜素或生育酚渗透,讨论了油菜冷驯化和去驯化过程中脂质结构与叶绿体膜中抗氧化剂含量的关系。