Genotypic variability in Populus tremula L. affects how anthropogenic nitrogen enrichment influences litter decomposition

Abstract

Background and aims Boreal forests can receive substantial nitrogen (N) enrichment via atmospheric N deposition and industrial forest fertilization. While it is known that N enrichment can impact ecosystem properties, such as litter decomposition, it remains poorly understood how genetic variability within plant species modifies these impacts. Methods We grew replicates of ten Populus tremula L. genotypes (GTs) under 3 N conditions; ambient, and levels representing atmospheric N deposition and industrial forest fertilization. We measured leaf and litter physical and chemical traits, and conducted a litter decomposition assay.

Aspen Leaves as a “Chemical Landscape” for Fungal Endophyte Diversity—Effects of Nitrogen Addition

“…Resource availability may further alter the relative investment in different defense mechanisms in plants ( López-Goldar et al, 2020 ), and earlier studies have shown that growing environment also determines aspens’ investment in CTs ( Decker et al, 2017 ). In our greenhouse study, the CT level was generally low as compared to other studies where the detection has been done against the same commercial standard (e.g., Bandau et al, 2016 ), but it is unclear if the low CT level had consequences for the responses of the fungal community in our study. A deeper taxonomic analysis, using culture-independent approaches, may be needed to reveal these relationships.…”

Genetic and environmental control of lignin biosynthesis and C emission from crop stover

“…The pilot conducted on the NAM founders demonstrated that genotype is significantly associated with C emission, as has been reported in previous studies involving tree species (Bandau et al, 2017;Li et al, 2017). These previous studies were, however, based on small numbers of genotypes and did not report on genotypic contributions to variation, nor did they provide estimates of heritability for C emission.…”

“…While previous studies have reported on the significance of genotype to intraspecific C emission (Bandau et al, 2017;Li et al, 2017), there are still no current reports on the specific genetic determinants of C emission and how these may relate to known biochemical effectors of C emission (i.e. lignin content, N content, etc.).…”

Compensatory phenolic induction dynamics in aspen after aphid infestation

“…Polyphenolic condensed tannins (CTs, the second major class of defense phenolic classes) are built from flavan-3-ol (catechin) units and in aspen vary considerably in concentration for example in response to anthropogenic nitrogen addition 13 , age and ontogeny 14 . Aspen genotypes’ ability to synthetise, accumulate and store CTs is heritable 15 allowing for relative characterization of CT producers within a population 16 . Flavan-3-ols that the CTs are made from are products of a branch pathway of anthocyanin biosynthesis 17 and polymerization to CTs appears to be a non-enzymatic process during which proanthocyanidin starter and extension dimers assemble in the vacuole 18 , however it is unknown whether in planta degradation of CTs can also be a spontaneous process.…”

“…Aspen trees ( Populus tremula ) are outcrossing and genetically diverse keystone species of the northern hemisphere 41 , 42 , that like North American aspen ( Populus tremuloides ), produce CT and SPG defence phenolic compounds in leaves, bark, and roots 3 , 23 , 25 , 43 , 44 that considerably contribute to the pool of total phenolics (TPs) 13 . In this study we used Aspen genotypes that represented a range of CT genotypes from the Swedish Aspen (SwAsp) collection 16 , 45 , to study the relationship between genotype specific constitutive CT concentrations and induced responses after two kinds of damage: infestation by Chaitophorus aphids and mechanical rupture. We show that aphid fecundity is negatively related to both TPs and CTs but not to specific SPGs.…”