Department of Evolutionary Biology, Ecology and Environmental Sciences, Faculty of Biology, University of Barcelona, Avinguda Diagonal 643, 08028, Barcelona, Spain.
Department of Evolutionary Biology, Ecology and Environmental Sciences, Faculty of Biology, University of Barcelona, Avinguda Diagonal 643, 08028, Barcelona, Spain.
J Plant Physiol. 2018 Dec;231:202-209. doi: 10.1016/j.jplph.2018.09.009. Epub 2018 Sep 25.
Cold stress response is mediated by multiple signaling pathways with complex interactions, among which phytohormones may play a role. We explored changes in the contents of phytohormones, including abscisic acid, jasmonic acid, salicylic acid, auxin, cytokinins, gibberellins and melatonin, along with stress tolerance markers in an invasive halophyte, Carpobrotus edulis in response to chilling. In a first experiment, plants were exposed to mean daily temperatures from 10 °C to 5 °C during a cold wave in an experimental garden. In a second experiment, plants were subject to slowly decreasing temperatures, from 20 to 5 °C, in a climatic chamber. Although the cold response in both experiments was associated with a similar extent of leaf desiccation, hormonal variations differed. Cold stress reduced melatonin contents, while it increased salicylic acid contents in the experimental garden. Rather, transient increases in the contents of melatonin occurred in parallel with sustained increases in the contents of abscisic acid and cytokinins in the climatic chamber. In both experiments, plants were able to prevent cold-induced increases in lipid peroxidation and any eventual damage to the photosynthetic apparatus. We conclude that (i) the hormonal response to chilling in C. edulis is strongly dependent on time exposure to low temperatures, severity of stress, as well as other environmental conditions, (ii) the hormonal response of this plant species to low temperatures is very plastic, thus underlining its great capacity for cold acclimation.
冷胁迫响应是由多个信号通路介导的，它们之间存在着复杂的相互作用，其中植物激素可能发挥作用。我们研究了在入侵性盐生植物海角菠萝（Carpobrotus edulis）中，植物激素（包括脱落酸、茉莉酸、水杨酸、生长素、细胞分裂素、赤霉素和褪黑素）含量以及胁迫耐受标记物的变化，以响应寒冷。在第一个实验中，植物在实验花园中经历寒冷天气时，暴露在 10-5°C 的日平均温度下。在第二个实验中，植物在气候室中，从 20°C 逐渐降至 5°C。尽管两个实验中的冷响应都伴随着相似程度的叶片萎蔫，但激素变化不同。寒冷胁迫降低了褪黑素的含量，而在实验花园中增加了水杨酸的含量。相反，在气候室中，褪黑素的含量短暂增加，与脱落酸和细胞分裂素的含量持续增加平行发生。在两个实验中，植物都能够防止冷诱导的脂质过氧化增加和对光合作用装置的任何潜在损害。我们得出结论：（i）C. edulis 对寒冷的激素反应强烈依赖于低温暴露时间、胁迫严重程度以及其他环境条件；（ii）该植物物种对低温的激素反应非常有弹性，从而突出了其对寒冷适应的巨大能力。
