Grassland species can influence the abundance of microbes on each other's roots

Abstract

NEIGHBOURING plants usually influence each other's growth. These interactions are very important in determining the composition and structure of plant communities, but much remains to be discovered about the mechanisms by which plants influence each other. Often plants compete for requirements such as light and mineral nutrients. Some plants exude substances which are toxic to others^1–3. Another possibility, as yet unexplored, is that interactions occur through changes in the microbial populations on the root surface or in the rhizosphere (the soil near the root surface). It is known that rhizosphere and root surface microorganisms can affect the plant's nutrient uptake and growth^4,5, but up to now there has been no evidence on whether plant species which naturally grow together can influence each other's microbial populations. We present here such evidence for two species common in British lowland grassland, Lolium perenne L. (perennial ryegrass) and Plantago lanceolata L. (ribwort plantain, a dicotyledonous species).