Abstract

Plants regulate molecular bioactivity in response to daily and seasonal environmental fluctuations in temperature, light, humidity, and precipitation. These rhythms interconnect, overlap, and feedback both into each other and into the plant’s endogenous circadian clock. The resulting regulatory network tightly ensures that the overall phytochemical composition is highly adaptive to the plant’s needs at any point in time. Temporally coordinated control of primary and secondary metabolism ensures phytochemicals are in tune with the demands of the environment and the available resources. As a consequence, phytochemical composition varies throughout the day and year. This variation in phytochemical abundance and composition across time can affect experimental results and conclusions. Understanding how phytochemical composition varies across time is critical for uncovering the underlying regulatory connections and ultimately improving the quality of phytochemical products. Herein, we review the mechanisms underlying diel and seasonal variations in phytochemical composition and provide examples of temporal regulation of specific compounds within phenol, terpenoid, and alkaloid phytochemical classes.

Graphic abstract

Temporal regulation of phytochemical composition. The phytochemical composition of a plant is under complex control, affected by both external environmental factors and endogenous circadian rhythms. The environmental factors that directly affect phytochemical profiles and concentrations themselves vary across time of day and time of year. These cyclic environmental factors also entrain the endogenous circadian clock which imposes additional regulation on the production and processing of many phytochemicals. This concerted effort to ensure phytochemicals are exquisitely in tune with the demands of the environment results in fluctuating phytochemical composition. Variation in phytochemical abundance and composition across time can affect experimental results and conclusions. Failing to consider the factors of time of day and year can result in misleading or inconsistent estimations of the potency and composition of phytochemical extractions. Integrating temporal factors will improve our understanding of the underlying regulatory connections and ultimately improve the quality of phytochemical products.

中文翻译：

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只是时间问题：每日和季节性节律对植物化学物质的影响

抽象的

植物响应温度，光照，湿度和降水的每日和季节性环境波动来调节分子生物活性。这些节律相互联系，重叠并相互反馈，并反馈到植物的内源性生物钟中。由此产生的监管网络可确保在任何时间点，总体植物化学成分都高度适应植物的需求。对初级和次级代谢的时间协调控制可确保植物化学物质与环境和可用资源的需求保持一致。结果，植物化学组成在一天和一年中都在变化。随着时间的流逝，植物化学丰度和组成的这种变化会影响实验结果和结论。了解植物化学成分随时间变化的方式对于发现潜在的监管联系并最终提高植物化学产品的质量至关重要。本文中，我们回顾了植物化学组成中diel和季节性变化的潜在机制，并提供了酚，萜类和生物碱植物化学类别内特定化合物的时间调控实例。

图形摘要

植物化学成分的时间调控。植物的植物化学组成受复杂的控制，受外部环境因素和内源性昼夜节律的影响。直接影响植物化学特征和浓度的环境因素本身在一天中的时间和一年中的时间中会有所不同。这些循环的环境因素还夹带了内生的生物钟，这对许多植物化学物质的生产和加工施加了额外的法规。确保植物化学物质与环境需求完美协调的共同努力导致植物化学成分的波动。随时间变化的植物化学丰度和组成会影响实验结果和结论。不考虑一天和一年中的时间因素会导致对植物化学提取物的效力和成分的估计产生误导或不一致。整合时间因素将增进我们对基本监管联系的理解，并最终提高植物化学产品的质量。