How Past and Present Influence the Foraging of Clonal Plants?

Abstract

Clonal plants spreading horizontally and forming a network structure of ramets exhibit complex growth patterns to maximize resource uptake from the environment. They respond to spatial heterogeneity by changing their internode length or branching frequency. Ramets definitively root in the soil but stay interconnected for a varying period of time thus allowing an exchange of spatial and temporal information. We quantified the foraging response of clonal plants depending on the local soil quality sampled by the rooting ramet (i.e. the present information) and the resource variability sampled by the older ramets (i.e. the past information). We demonstrated that two related species, Potentilla reptans and P. anserina, responded similarly to the local quality of their environment by decreasing their internode length in response to nutrient-rich soil. Only P. reptans responded to resource variability by decreasing its internode length. In both species, the experience acquired by older ramets influenced the plastic response of new rooted ramets: the internode length between ramets depended not only on the soil quality locally sampled but also on the soil quality previously sampled by older ramets. We quantified the effect of the information perceived at different time and space on the foraging behavior of clonal plants by showing a non-linear response of the ramet rooting in the soil of a given quality. These data suggest that the decision to grow a stolon or to root a ramet at a given distance from the older ramet results from the integration of the past and present information about the richness and the variability of the environment.

Clonality as a driver of spatial genetic structure in populations of clonal tree species

“…Prolonged clonal growth along with selection and/or inter-clonal competition may eliminate less adapted clones, leading to monoclonal patches (Vandepitte et al 2009) and/ or genetic impoverishment of a population (Silvertown 2008). Also, clonal reproduction may enhance SGS in natural plant populations which may have profound genetic consequences (Chung et al 2005;Chenault et al 2011;Binks et al 2015) On the other hand, clonality confers important ecological advantages, such as the foraging response of plants (Louâpre et al 2012), reallocation of resources between ramets enabling avoidance from environmental stochasticity, and withstanding environmental perturbations or division of labour between connected ramets (Fischer and Kleunen 2001). Clonal plants life history traits show plasticity that allows them for dynamic interaction with habitat.…”

AM fungi patchiness and the clonal growth of Glechoma hederacea in heterogeneous environments

“…This may be due to a “lag time” in the plant’s response based on the need for environmental sampling. Indeed, Louâpre et al , (2012) demonstrated that clonal plants may need a minimum number of sampling points as benchmarks in order to perceive and respond to resource availability35. In their study, Potentilla reptans and P. anserina started to respond to the treatment after the 5 th internode, suggesting a strong effect of patch size.…”

“…The choice of these four ramets thus ensured that the clone had enough sampling points to assess the quality of its habitat i.e. in the patches where AM fungi were present or absent, in the heterogeneous treatments, and to adjust accordingly when initiating new ramets35. Each ramet was carefully washed after harvesting.…”

A simple model for the influence of habitat resource availability on lateral clonal spread

“…Such systems are numerous, with clonal spread being especially subject to recurrent investigation in plant ecology [13,43,44]. The particular example that we examined lies at the intersection of two areas of interest in plant ecology: the role of ramet positioning in small-scale vegetation composition [45][46][47][48] and ramet placement plasticity and its effect on plant behaviour [10,49,50]. Our model can serve as a suitable null model of ramet positioning to test hypotheses regarding environmental effects, enabling further inquiry into both of these topics.…”