Genetic by environment interactions affect plant–soil linkages

Abstract

The role of plant intraspecific variation in plant–soil linkages is poorly understood, especially in the context of natural environmental variation, but has important implications in evolutionary ecology. We utilized three 18- to 21-year-old common gardens across an elevational gradient, planted with replicates of five Populus angustifolia genotypes each, to address the hypothesis that tree genotype (G), environment (E), and G × E interactions would affect soil carbon and nitrogen dynamics beneath individual trees. We found that soil nitrogen and carbon varied by over 50% and 62%, respectively, across all common garden environments. We found that plant leaf litter (but not root) traits vary by genotype and environment while soil nutrient pools demonstrated genotype, environment, and sometimes G × E interactions, while process rates (net N mineralization and net nitrification) demonstrated G × E interactions. Plasticity in tree growth and litter chemistry was significantly related to the variation in soil nutrient pools and processes across environments, reflecting tight plant–soil linkages. These data overall suggest that plant genetic variation can have differential affects on carbon storage and nitrogen cycling, with implications for understanding the role of genetic variation in plant–soil feedback as well as management plans for conservation and restoration of forest habitats with a changing climate.

Cryptic eco‐evolutionary dynamics

“…Importantly, however, the different genotypes also showed markedly different norms of reaction, and so two genotypes that differed in phenotype in one environment were often similar in another. Importantly, those patterns cascaded to influence soil chemistry and mineralization, 194 suggesting the same considerations apply to linked ecological effects of evolution. In general, comparing genotypes across a range of environments is preferable to comparing them in one environment, …”

“…192,193 However, for our current consideration of cryptic outcomes at the link between selection and genetic responses, the biggest issue might be where and how we assess evolutionary responses to selection, as revealed by wellconducted common-garden or reciprocal transplant studies. For example, Pregitzer et al 194 compared different genotypes of narrowleaf cottonwood (Populus angustifolia) reared at three different locations along an elevational gradient. As has commonly been the case for such common garden studies since their earliest use, 195 the trait values of the genotypes varied with environment, consistent with norms of reaction.…”

Plant genetic effects on soils under climate change

“…All populations are genetically variable, and thus all foundation plant species populations are prone to exhibit phenotypic variation that impacts soil communities. The effect of intra-specific variation can be smaller, as large, or larger, than species-level comparisons, the relative importance of which is likely to be context specific (Crutsinger et al 2009;Schweitzer et al 2012;Pregitzer et al 2013). However, the relative importance of intra-specific variation relative to interspecific variation is less important than the specific genetic interactions among plants and their soils, which are common in a diversity of systems .…”

Macronutrients and metals released from soils by solutions of naturally occurring phenols

“…Specific activities for a few phenols have been identified, but the roles of most phenolic compounds remain undiscovered. It has been suggested that an important activity of plant phenols may be mediation of soil properties by changing availability of nutrients in the soil ( Pregitzer et al, ). Our recent studies on the activities of plant phenols in soils including examinations of C/N dynamics ( Halvorson and Gonzalez , ; Halvorson et al, ), ion exchange capacity ( Halvorson et al., ), and micro‐ and macronutrients ( Schmidt et al, ) provide support for that hypothesis.…”