Climate Change Effects on Secondary Compounds of Forest Trees in the Northern Hemisphere

Abstract

Plant secondary compounds (PSCs), also called secondary metabolites, have high chemical and structural diversity and appear as non-volatile or volatile compounds. These compounds may have evolved to have specific physiological and ecological functions in the adaptation of plants to their growth environment. PSCs are produced by several metabolic pathways and many PSCs are specific for a few plant genera or families. In forest ecosystems, full-grown trees constitute the majority of plant biomass and are thus capable of producing significant amounts of PSCs. We summarize older literature and review recent progress in understanding the effects of abiotic and biotic factors on PSC production of forest trees and PSC behavior in forest ecosystems. The roles of different PSCs under stress and their important role in protecting plants against abiotic and biotic factors are also discussed. There was strong evidence that major climate change factors, CO2 and warming, have contradictory effects on the main PSC groups. CO2 increases phenolic compounds in foliage, but limits terpenoids in foliage and emissions. Warming decreases phenolic compounds in foliage but increases terpenoids in foliage and emissions. Other abiotic stresses have more variable effects. PSCs may help trees to adapt to a changing climate and to pressure from current and invasive pests and pathogens. Indirect adaptation comes via the effects of PSCs on soil chemistry and nutrient cycling, the formation of cloud condensation nuclei from tree volatiles and by CO2 sequestration into PSCs in the wood of living and dead forest trees.

Tree defence and bark beetles in a drying world: carbon partitioning, functioning and modelling

“…This response is often due to reduced starch, which can occur despite increased sugar concentrations – a finding consistent with the role of soluble sugars as osmolytes (Dietze et al ., ). Similar to NSC dynamics, SM response to drought is not consistent, and can vary with the timing and severity of drought, the age and size of the tree, the type and ontogeny of the organ, and the class of SM (Jamieson et al ., ; Holopainen et al ., ). The lack of concurrent assessments of NSC and SMs in most drought experiments makes it difficult to mechanistically link SM dynamics to the carbon balance and to derive allocation trade‐offs (Ryan et al ., ).…”

Search for top-down and bottom-up drivers of latitudinal trends in insect herbivory in oak trees in Europe

“…Latitudinal variation in plant-herbivore interactions is therefore generally associated with large-scale variability in climatic conditions (Moreira et al, 2018) and numerous studies demonstrate an effect of temperature and precipitation on plant traits (e.g. leaf N, phenolic compounds) (Chen et al, 2013;Holopainen et al, 2018;Gely et al, 2019) and herbivory (Jamieson et al, 2015;Gely et al, 2019). However, many regions deviate from the global trend in temperature and precipitation toward higher latitudes due to their proximity to oceans or the presence of mountains (De Frenne et al, 2013), which can markedly change the relationship between latitude and plant-herbivore-predator interactions (Roslin et al, 2017;Loughnan & Williams, 2019;Moreira et al, 2019).…”

Variation in root secondary metabolites is shaped by past climatic conditions

“…As a chemical interface between plants and their environment, some plant secondary metabolites vary highly in concentration and composition with changing abiotic conditions (Holopainen et al, 2018; Jakobsen & Olsen, 1994; Selmar & Kleinwächter, 2013). Fluctuating patterns of sesquiterpene lactones and phenolics produced by Tithonia diversifolia, for instance, correlate with seasonal changes in temperature and rainfall (Sampaio, Edrada-Ebel, & Da Costa, 2016).…”