Mechanisms of frost resistance in Arabidopsis thaliana
Mechanisms of frost resistance in Arabidopsis thaliana
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DOI：
10.1007/s00425-018-2939-1
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发表时间：
2018-10-01
期刊：
影响因子：
4.3
通讯作者：
Heyer, Arnd G.
中科院分区：
文献类型：
--
作者：
Hoermiller, Imke I.;Ruschhaupt, Moritz;Heyer, Arnd G.
主要结论 拟南芥的抗冻策略因来源而异。南方种质可能会避免或耐受冷冻，而北方种质则始终能够耐受并在驯化过程中减少可冻结组织水的比例。通过避免或耐受细胞外冰的形成可以实现零度以下的生存。相互矛盾的证据表明，拟南芥的离体叶子要么是防冻的，要么是耐冻的。在这里，我们使用来自不同生境的三种不同的天然拟南芥种质来研究土壤中整株植物的抗冻策略。将植物冷却至固定温度或仅将其保持在各自的冰核温度不同的时间间隔。将整个植物的组织损伤与针对具有外部冰核的分离叶子确定的标准致死温度进行比较。当在温和的零度以下的温度下从外部引发冰核时，所有分离的叶子都能幸存下来，但南方种质的整个植物在非驯化状态下表现出避免冻结的行为。北方种质和所有冷驯化植物均具有耐冻性，但冷冻事件的持续时间会影响组织损伤。因为这表明细胞脱水是损伤机制，所以测定了叶子中可冷冻水的比例和细胞液的渗透压。事实上，与冷驯化状态下的敏感种质C24相比，耐冷冻种质Rsch具有较低比例的可冷冻水和较高的细胞液渗透压。
Main conclusion Freezing resistance strategies vary in Arabidopsis depending on origin. Southern accessions may avoid or tolerate freezing, while northern ones are always tolerant and reduce the proportion of freezable tissue water during acclimation.Survival of sub-zero temperatures can be achieved by either avoiding or tolerating extracellular ice formation. Conflicting evidence has been presented showing that detached leaves of Arabidopsis thaliana are either freeze avoiding or tolerant. Here, we used three different natural Arabidopsis accessions from different habitats to investigate the frost resistance strategy of whole plants in soil. Plants were cooled to fixed temperatures or just held at their individual ice nucleation temperature for different time intervals. Tissue damage of whole plants was compared to the standard lethal temperature determined for detached leaves with external ice nucleation. While all detached leaves survived freezing when ice nucleation was externally initiated at mild sub-zero temperatures, whole plants of the southern accession behaved as freeze avoiding in the non-acclimated state. The northern accessions and all cold acclimated plants were freezing tolerant, but the duration of the freezing event affected tissue damage. Because this pointed to cell dehydration as mechanism of damage, the proportion of freezable water in leaves and osmolality of cell sap was determined. Indeed, the freezing tolerant accession Rsch had a lower proportion of freezable water and higher cell sap osmolality compared to the sensitive accession C24 in the cold acclimated state.