Concentrations of Foliar Quercetin in Natural Populations of White Birch (Betula pubescens) Increase with Latitude

Abstract

We investigated latitudinal and regional variations in the composition and concentrations of foliar flavonoids and condensed tannins in wild populations of white birch (Betula pubescens EHRH) in a large climatic transect in Finland. Concentrations of quercetin derivatives were correlated positively with latitude. By contrast, the concentrations of apigenin and naringenin derivatives were correlated negatively with latitude. These compound-specific latitudinal gradients compensated each other, resulting in no changes in the concentration of total flavonoids. Our results thus demonstrate a qualitative, but not quantitative, latitude-associated gradient in the foliar flavonoids in white birch. Due to higher antioxidant capacity of the quercetin derivatives in relation to other flavonoids, the qualitative change can reflect higher adaptation to light in the north than south. An investigation on a regional scale in the northern boreal zone showed that the temperature sum was correlated positively and soil P concentration was correlated negatively with the concentrations of foliar flavonoid, while the concentration of condensed tannins was correlated with slope. The variation in concentrations of flavonoids at large-scale geographical patterns is in line with the conjecture that foliar flavonoids are synthesized for protection against photooxidative stress.

A Meta-Analysis of the Global Distribution Pattern of Condensed Tannins in Tree Leaves

“…Therefore, a higher allocation to defensive substances may be advantageous for plants growing in the warmer regions. However, some other studies did not find clear relationships between CT abundance and air temperature or latitude (Stark et al 2008). Adams et al (2009a) also showed only limited latitudinal trends in the concentrations of CT's, or other defensive compounds.…”

Impact of Elevated Levels of Atmospheric CO2 and Herbivory on Flavonoids of Soybean (Glycine max Linnaeus)

“…Whereas leaf damage in the form of skeletonization induces changes in several flavonoid and isoflavonoid levels, feeding damage by the caterpillar V. cardui increased levels of one genistein glycoside, and feeding by the aphid A. glycines did not affect production of any compound. The increase in flavonoid content over time is to be expected as these compounds are induced by herbivore damage (Hagerman and Butler 1991), and by increased photooxidative stress, particularly in August when the aphid experiments were conducted (Stark et al 2008).…”

Phenolic Composition and Antioxidant Capacity of Bilberry (Vaccinium myrtillus) Leaves in Northern Europe Following Foliar Development and Along Environmental Gradients

“…Consequently, the quality and quantity of phenolics are expected to differ among bilberry leaves growing in different parts of the country. Previous studies have shown that the phenolic content in juniper (Juniperus communis) and birch (Betula pubescens) leaves increases with latitude (Stark et al, 2008;Martz et al, 2009). However, although the effect of altitude and/or latitude on AC content of bilberry fruit has been previously shown (Lätti et al, 2008;Rieger et al, 2008), no data are available about changes of phenolic composition in bilberry leaves along large geographical gradients.…”