• Energy Research

AbstractPlant secondary metabolites (SMs) play crucial roles in plant‐environment interactions and contribute greatly to human health. Global climate changes are expected to dramatically affect plant secondary metabolism, yet a systematic understanding of such influences is still lacking. Here, we employed medicinal and aromatic plants (MAAPs) as model plant taxa and performed a meta‐analysis from 360 publications using 1828 paired observations to assess the responses of different SMs levels and the accompanying plant traits to elevated carbon dioxide (eCO2), elevated temperature (eT), elevated nitrogen deposition (eN) and decreased precipitation (dP). The overall results showed that phenolic and terpenoid levels generally respond positively to eCO2 but negatively to eN, while the total alkaloid concentration was increased remarkably by eN. By contrast, dP promotes the levels of all SMs, while eT exclusively exerts a positive influence on the levels of phenolic compounds. Further analysis highlighted the dependence of SM responses on different moderators such as plant functional types, climate change levels or exposure durations, mean annual temperature and mean annual precipitation. Moreover, plant phenolic and terpenoid responses to climate changes could be attributed to the variations of C/N ratio and total soluble sugar levels, while the trade‐off supposition contributed to SM responses to climate changes other than eCO2. Taken together, our results predicted the distinctive SM responses to diverse climate changes in MAAPs and allowed us to define potential moderators responsible for these variations. Further, linking SM responses to C‐N metabolism and growth‐defence balance provided biological understandings in terms of plant secondary metabolic regulation.

Climate changes have unpredictable effects on ecosystems and agriculture. Plants adapt metabolically to overcome these challenges, with plant secondary metabolites (PSMs) being crucial for plant-environment interactions. Thus, understanding how PSMs respond to climate change is vital for future cultivation and breeding strategies. Here, we review PSM responses to climate changes such as elevated carbon dioxide, ozone, nitrogen deposition, heat and drought, as well as a combinations of different factors. These responses are complex, depending on stress dosage and duration, and metabolite classes. We finally identify mechanisms by which climate change affects PSM production ecologically and molecularly. While these observations provide insights into PSM responses to climate changes and the underlying regulatory mechanisms, considerable further research is required for a comprehensive understanding.

AbstractOilseed crops are widely planted and are closely associated with human nutrition and health. Globally, increased nitrogen (N) deposition has a significant impact on agricultural production; however, in‐depth knowledge of oilseed crop yields and quality is still lacking. Here, we performed a global meta‐analysis from 128 published papers with 462 paired observations to evaluate the response of oilseed crop yields, yield composition, protein, and oil content to simulated N deposition. The meta‐analysis showed that simulated N deposition significantly increased oilseed crop yields in a dose‐dependent and duration‐dependent manner. The yield compositions were also changed by N deposition, where pod numbers per plant (PNP) and seed weights per pod were significantly increased. Interestingly, our analysis identified PNP as the key factor determining the oilseed crop yield response to simulated N deposition. Additionally, the form of N deposition had no striking influence on either yields or yield components, whereas differences in the sensitivity in rape responses reflected differences in crop species. In terms of oilseed crop quality, although simulated N deposition increased the seed protein content in a dose‐dependent manner, there was a significant negative impact on the seed oil content. Furthermore, this negative correlation between seed oil content and biomass under simulated N deposition implies adverse effects caused by a dilution effect. Overall, our results suggest discrete responses of oilseed crop yield, seed protein and oil content to simulated N deposition. This study has ecological and biological implications for oilseed crop yield and quality responses facing global N deposition.

Plant secondary metabolites (SMs) play crucial roles in plant-environment interactions and contribute greatly to human health. Global climate changes are expected to dramatically affect plant secondary metabolism, yet a systematic understanding of such influences is still lacking. Here, we employed medicinal and aromatic plants (MAAPs) as model plant taxa and performed a meta-analysis from 360 publications using 1828 paired observations to assess the responses of different SMs levels and the accompanying plant traits to elevated carbon dioxide (eCO2), elevated temperature (eT), elevated nitrogen deposition (eN), and decreased precipitation (dP). The overall results showed that phenolic and terpenoid levels generally respond positively to eCO2 but negatively to eN, while the total alkaloid concentration was increased remarkably by eN. By contrast, dP promotes the levels of all SMs, while eT exclusively exerts a positive influence on the levels of phenolic compounds. Further analysis highlighted the dependence of SM responses on different moderators such as plant functional types, climate change levels or exposure durations, mean annual temperature and mean annual precipitation. Moreover, plant phenolic and terpenoid responses to climate changes could be attributed to the variations in C/N ratio and total soluble sugar levels, while the trade-off supposition contributed to SM responses to climate changes other than eCO2. Taken together, our results predicted the distinctive SM responses to diverse climate changes in MAAPs, and allowed us to define potential moderators responsible for these variations. Further, linking SM responses to C-N metabolism and growth-defence balance provided biological understandings in terms of plant secondary metabolic regulation. Peer-reviewed journal articles published online from January 1990 to March 2022 were searched using Web of Science (http://www.isiknowledge.com/), with the following terms: (global change OR climate change OR free-air carbon dioxide enrichment OR free-air CO2 enrichment OR elevated carbon dioxide OR elevated CO2 OR elevated atmospheric CO2 OR CO2 enrichment OR eCO2 OR atmospheric CO2 enrichment OR elevated atmospheric carbon dioxide OR carbon dioxide enrichment OR [carbon dioxide] OR nitrogen deposition OR nitrogen addition OR nitrogen application OR nitrogen fertiliz* OR nitrogen nutrition OR N deposition OR N addition OR N application OR N fertiliz* OR N nutrition OR changing precipitation OR increased precipitation OR decreased precipitation OR drought OR water stress OR water addition OR warming OR elevated temperature OR climate warming OR elevated temperature OR increased temperature) AND (medicinal plant OR aromatic plants).