Biosynthesis of certain secondary metabolites, as a relief response to the severe environmental stress of the mediterranean summer, is a major reaction of the plants thriving in areas with mediterranean-type climate. Some of these compounds are of great importance to both humans and the environment. Tracing of certain secondary metabolites, after the exposure of Olea europaea L. individuals to stressing environmental conditions, is the aim of this investigation. Our two-day cycle, detailed data indicate that soon after the summer mid-day severe environmental stress, a threefold increase (+ 256%) in reactive oxygen species accumulation is recorded in the leaves while the absorbance of the photosynthetic pigments is drastically reduced (up to − 60%). Then, the secondary metabolic pathway of the shikimic acid is activated and the expression level of l-Dopa decarboxylase—an enzyme common to plants and animals, bisconnected to this pathway—is rapidly increased in order to metabolize the highly toxic l-Dopa or the amino acid l-tyrosine, to dopamine or tyramine, respectively. These reactions promote, at a certain period of the 24-h cycle, the biosynthesis of oleuropein (41% increase), an antioxidant phenolic compound possessing a wide range of important pharmacological properties. By the evening twilight, when the environmental conditions turn to mild, the cell functions reset to normal.

中文翻译：

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Olea europaea L. 叶片的综合环境胁迫及某些次生代谢物的生物合成缓解机制

某些次生代谢物的生物合成，作为对地中海夏季严重环境压力的缓解反应，是地中海型气候地区植物繁盛的主要反应。其中一些化合物对人类和环境都非常重要。本次调查的目的是在 Olea europaea L. 个体暴露于压力环境条件后追踪某些次生代谢物。我们为期两天的周期，详细数据表明，在夏季中午严重的环境压力之后不久，叶子中活性氧的积累增加了三倍（+ 256％），而光合色素的吸光度则急剧下降（高达 − 60%）。然后，莽草酸的次级代谢途径被激活，L-多巴脱羧酶（一种植物和动物常见的酶，与该途径相互关联）的表达水平迅速增加，以代谢剧毒的左旋多巴或氨基酸l-酪氨酸，分别为多巴胺或酪胺。这些反应在 24 小时循环的某个时期促进了橄榄苦苷的生物合成（增加了 41%），这是一种具有广泛重要药理特性的抗氧化酚类化合物。到傍晚时分，当环境条件变得温和时，细胞功能就会恢复正常。分别。这些反应在 24 小时循环的某个时期促进了橄榄苦苷的生物合成（增加了 41%），这是一种具有广泛重要药理特性的抗氧化酚类化合物。到傍晚时分，当环境条件变得温和时，细胞功能就会恢复正常。分别。这些反应在 24 小时循环的某个时期促进了橄榄苦苷的生物合成（增加了 41%），这是一种具有广泛重要药理特性的抗氧化酚类化合物。到傍晚时分，当环境条件变得温和时，细胞功能就会恢复正常。