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Non-structural carbohydrates (NSCs), as the labile fraction and dominant carbon currency, are essential mediators of plant adaptation to environments. However, whether and how NSC coordinates with plant economic strategy frameworks, particularly the well-recognized leaf economics spectrums (LES) and root economics space (RES), remains unclear. We examined the relationships between NSC and key plant economics traits in leaves and fine roots across 90 alpine coniferous populations on the Tibetan Plateau, China. We observed contrasting coordination of NSC with economics traits in leaves and roots. Leaf total NSC and soluble sugar aligned with the leaf economic spectrum, conveying a trade-off between growth and storage in leaves. However, NSC in roots was independent of the root economic spectrum, but highly coordinated with root foraging, with more starch and less sugar in forage-efficient, thinner roots. Further, NSC-trait coordination in leaves and roots was, respectively, driven by local temperature and precipitation. These findings highlight distinct roles of NSC in shaping the above- and belowground multidimensional economics trait space, and NSC-based carbon economics provides a mechanistic understanding of how plants adapt to heterogeneous habitats and respond to environmental changes. 

An exponential rise in the atmospheric vapour pressure deficit (VPD) is among the most consequential impacts of climate change in terrestrial ecosystems. Rising VPD has negative and cascading effects on nearly all aspects of plant function including photosynthesis, water status, growth and survival. These responses are exacerbated by land–atmosphere interactions that couple VPD to soil water and govern the evolution of drought, affecting a range of ecosystem services including carbon uptake, biodiversity, the provisioning of water resources and crop yields. However, despite the global nature of this phenomenon, research on how to incorporate these impacts into resilient management regimes is largely in its infancy, due in part to the entanglement of VPD trends with those of other co-evolving climate drivers. Here, we review the mechanistic bases of VPD impacts at a range of spatial scales, paying particular attention to the independent and interactive influence of VPD in the context of other environmental changes. We then evaluate the consequences of these impacts within key management contexts, including water resources, croplands, wildfire risk mitigation and management of natural grasslands and forests. We conclude with recommendations describing how management regimes could be altered to mitigate the otherwise highly deleterious consequences of rising VPD. 

Frequent observations of higher mortality in larger trees than in smaller ones during droughtshave sparked an increasing interest in size-dependent drought-induced mortality. However, theunderlying physiological mechanisms are not well understood, with height-associated hydraulicconstraints often being implied as the potential mechanism driving increased droughtvulnerability. We performed a quantitative synthesis on how key traits that drive plant waterand carbon economy change with tree height within species and assessed the implications thatthe different constraints and compensations may have on the interacting mechanisms (hydraulicfailure, carbon starvation and/or biotic-agent attacks) affecting tree vulnerability to drought.While xylem tension increases with tree height, taller trees present a range of structural andfunctional adjustments, including more efficient water use and transport and greater wateruptake and storage capacity, that mitigate the path-length-associated drop in water potential.These adaptations allow taller trees to withstand episodic water stress. Conclusive evidence forheight-dependent increased vulnerability to hydraulic failure and carbon starvation, and theircoupling to defence mechanisms and pest and pathogen dynamics, is still lacking. Furtherresearch is needed, particularly at the intraspecific level, to ascertain the specific conditions andthresholds above which height hinders tree survival under drought.