Núcleo de Pesquisa em Fisiologia e Bioquímica, Instituto de Botânica São Paulo, Brazil.
Departamento de Ecologia, Universidade de São Paulo São Paulo, Brazil.
Front Plant Sci. 2014 Mar 14;5:96. doi: 10.3389/fpls.2014.00096. eCollection 2014.
Barbacenia purpurea is a resurrection species endemic to rock outcrops, in Rio de Janeiro, Brazil. It tolerates great temperature variations, which are associated to periods of up to 30 days without precipitation. Using a metabolomic approach, we analyzed, under winter and summer conditions, changes in the leaf metabolite profile (MP) of potted plants of B. purpurea submitted to daily watered and water deficit for at least 20 days and subsequent slow rehydration for 5 days. Leaves were collected at different time points and had their MP analyzed by GC/MS, HPAEC, and UHPLC techniques, allowing the identification of more than 60 different compounds, including organic and amino acids, sugars, and polyols, among others. In the winter experiment, results suggest the presence of two time-dependent responses in B. purpurea under water stress. The first one starts with the increase in the content of caffeoyl-quinic acids, substances with strong antioxidant activity, until the 16th day of water suppression. When RWC reached less than 80 and 70%, in winter and summer respectively, it was observed an increase in polyols and monosaccharides, followed by an increment in the content of RFO, suggesting osmotic adjustment. Amino acids, such as GABA and asparagine, also increased due to 16 days of water suppression. During rehydration, the levels of the mentioned compounds became similar to those found at the beginning of the experiment and when compared to daily watered plants. We conclude that the tolerance of B. purpurea to dehydration involves the perception of water deficit intensity, which seems to result in different strategies to overcome the gradient of water availability imposed along a certain period of stress mainly during winter. Data from summer experiment indicate that the metabolism of B. pupurea was already primed for drought stress. The accumulation of phenolics in summer seemed to be more temperature and irradiance-dependent than on the RWC.
巴卡西亚那 Purpurea 是一种复活物种，分布于巴西里约热内卢的岩石露头处。它能耐受很大的温度变化，这些变化与长达 30 天没有降水的时期有关。使用代谢组学方法，我们分析了冬季和夏季条件下，将盆栽巴卡西亚那 Purpurea 置于每日浇水和至少 20 天缺水以及随后 5 天缓慢复水的条件下，其叶片代谢物谱（MP）的变化。在不同时间点采集叶片，并通过 GC/MS、HPAEC 和 UHPLC 技术分析其 MP，鉴定出 60 多种不同的化合物，包括有机和氨基酸、糖和多元醇等。在冬季实验中，结果表明，在水分胁迫下，巴卡西亚那 Purpurea 存在两种时间依赖性反应。第一个反应从 16 天的水分抑制开始，增加咖啡酰奎宁酸的含量，这些物质具有很强的抗氧化活性。当冬季和夏季的 RWC 分别低于 80%和 70%时，观察到多元醇和单糖的增加，随后是 RFO 含量的增加，表明渗透调节。由于 16 天的水分抑制，氨基酸，如 GABA 和天冬酰胺，也增加了。在复水过程中，这些化合物的含量变得与实验开始时相似，与每日浇水的植物相比也相似。我们得出结论，巴卡西亚那 Purpurea 对脱水的耐受性涉及对水分胁迫强度的感知，这似乎导致了不同的策略来克服在一定的压力期间主要在冬季施加的水分可利用性梯度。夏季实验的数据表明，巴卡西亚那 Purpurea 的代谢已经为干旱胁迫做好了准备。夏季酚类物质的积累似乎更多地依赖于温度和光照，而不是 RWC。
