The term “rhizosphere” was coined by Lorenz Hiltner in 1904 (Hartmann et al. 2008). Based on investigations on the germination and growth of different crop plants, Hiltner realised that root exudates of different plants support the development of different microbial communities and that plant nutrition is affected by the microbial composition of the rhizosphere. Beneficial bacteria are attracted by root exudates, whilst others adjust to the specific root exudates. Hiltner tightly linked breakthroughs in basic research to improved rhizosphere management practices.
We have come a long way since Hiltner’s pioneering research. We now know that some rhizosphere interactions involve intricate systems of communication, which in the case of symbioses such as the arbuscular mycorrhizal symbiosis are several hundreds of millions years old; others involve the release of exudates from roots, and other products of rhizodeposition that are used as substrates for soil microorganisms (Lambers et al. 2009). Rhizosphere processes in the long run are central to biogeochemical cycles, soil formation and Earth history (Harrison et al. 2010). Major anticipated discoveries will enhance our basic understanding and allow applications of new knowledge to deal with nutrient deficiencies, pests and diseases, and the challenges of increasing global food production and agroecosystem productivity in an environmentally responsible manner.
Harrison JA, Bouwman AF, Mayorga E and Seitzinger S 2010 Magnitudes and sources of dissolved inorganic phosphorus inputs to surface fresh waters and the coastal zone: A new global model Global Biogeochemical Cycles 24:16.
Hartmann A, Rothballer M and Schmid M 2008 Lorenz Hiltner, a pioneer in rhizosphere microbial ecology and soil bacteriology research. Plant Soil 312:7-14
Lambers H, Mougel C, Jaillard B and Hinsinger P 2009 Plant-microbe-soil interactions in the rhizosphere: an evolutionary perspective. Plant Soil 321:83-115
Links to resources and suppliers
Readers may also be interested to visit http://roots.psu.edu/, a useful site for methods belowground.