Using plant traits to explain plant–microbe relationships involved in nitrogen acquisition

Abstract

It has long been recognized that plant species and soil microorganisms. are tightly linked, but understanding how different species vary in their effects on soil is currently limited. In this study, we identified those. plant characteristics (identity, specific functional traits, or resource acquisition strategy) that were the best predictors of nitrification and denitrification processes. Ten plant populations representing eight species collected from three European grassland sites were chosen for their contrasting plant trait values and resource acquisition strategies. For each individual plant, leaf and root traits and the associated potential microbial activities (i.e., potential denitrification rate [DEA], maximal nitrification rate [NEA], and NH4+ affinity of the microbial community [NHScom]) were measured at two fertilization levels under controlled growth conditions. Plant traits were powerful predictors of plant-microbe interactions, but relevant plant traits differed in relation to the microbial function studied. Whereas denitrification was linked to the relative growth rate of plants, nitrification was strongly correlated to root trait characteristics (specific root length, root nitrogen concentration, and plant affinity for NH4+) linked to plant N cycling. The leaf economics spectrum (LES) that commonly serves as an indicator of resource acquisition strategies was not correlated to microbial activity. These results suggest that the LES alone is not a good predictor of microbial activity, whereas root traits appeared critical in understanding plant-microbe interactions.

Plant community controls on short‐term ecosystem nitrogen retention

“…However, this unexplained variation might point to the importance of particular groups of microbes and their activities, which can be linked to plant functional traits, for explaining variation in 15 N pools (e.g. Cantarel et al ., 2015; Moreau et al ., 2015). …”

Grassland species root response to drought: consequences for soil carbon and nitrogen availability

“…Indeed, in recent work, root traits have been shown to explain a range of ecosystem properties and processes better than leaf traits. For example, root traits have been found to explain soil microbial community composition better than leaf traits in field and pot experiments (Legay et al 2014;Orwin et al 2010), as well as the availability of inorganic N and rates of denitrification and nitrification (Cantarel et al 2015;Moreau et al 2015;Orwin et al 2010), and plant performance at a population level (Schroeder-Georgi et al 2016).…”

Seedling root responses to soil moisture and the identification of a belowground trait spectrum across three growth forms

“…For example, Roumet et al (2006) found evidence that annuals may be separated from perennials by a rapid resource acquisition strategy with high SRL and root N concentrations; however, differences between grasses, forbs, and legumes were less clear. Even as efforts to characterize root function have expanded, comparative efforts are often restricted to a few species or a single growth form (Chen et al, 2013;Valverde-Barrantes et al, 2013;Kong et al, 2014;Cantarel et al, 2015;Liu et al, 2015), making it unclear whether general patterns of root responses differ predictably across a range of woody and herbaceous growth forms.…”