Genetic-based legacy effects of above- and belowground linkages on plant community and fitness

Background/Question/Methods

Genetic-based plant-soil feedbacks contribute to the expanding field of eco-evo dynamics and improve our understanding of the ecological and evolutionary consequences of changing species ranges. Plant-soil feedbacks may promote the ability of soils to be agents of selection, thus possibly promoting evolutionary responses to a range of global change factors on a contemporary timescale. Plant-soil feedback studies so far have focused largely on species-specific feedbacks. We hypothesized that legacy effects of plant growth in soil would impact the growth and performance of other plants when reciprocally planted in each other’s soils and that these effects would be observed at both the species and genotype levels. To test these hypotheses, we utilized the legacy effects of soils previously conditioned by genotypes of two species, Solidago altissima and S. gigantea, by growing genotypes of these two species in previously conditioned soils and in a control soil in a common-garden experiment. 

Results/Conclusions

We found evidence for both species- and genotype-specific plant-soil feedbacks associated with previously conditioned soils of the same species and genotypes. These feedbacks were largely related to community responses and to plant fitness. Negative feedbacks on S. altissima indicated that the species (and genotypes) were generally less susceptible to herbivory and pathogens but had fewer ramets and a diminished development of flower buds when grown in soils previously conditioned by S. altissima genotypes. In contrast, positive to neutral feedbacks were observed for the same variables for S. gigantea (and genotypes) when grown in soils previously conditioned by S. gigantea genotypes, although there were no differences in number of ramets. These genetic-based legacy effects have implications for our understanding of eco-evo dynamics and how species may differentially respond to global change factors as well as emphasize the importance of both inter- and intraspecific variation as related to genetic-based plant-soil feedbacks.