Plant and Soil

, Volume 267, Issue 1–2, pp 235–241 | Cite as

Bacterial inoculation of maize affects carbon allocation to roots and carbon turnover in the rhizosphere



To assess the influence of bacteria inoculation on carbon flow through maize plant and rhizosphere,14C allocation after14CO2 application to shoots over a 5-day period was determined. Plants were grown on C- and N-free quartz sand in two-compartment pots, separating root and shoot space. While one treatment remained uninoculated, treatments two and three were inoculated withPantoea agglomerans (D5/23) andPseudomonas fluorescens (Ps I A12), respectively, five days after planting. Bacterial inoculation had profound impacts on carbon distribution within the system. Root/rhizosphere respiration was increased and more carbon was allocated to roots of plants being inoculated. After five days of14CO2 application, more ethanol-soluble substances were found in roots of inoculated treatments and lower rhizodeposition indicated intensive C turnover in the rhizosphere. In both inoculated treatments the intensity of photosynthesis measured as net-CO2-assimilation rates were increased when compared to the uninoculated plants. However, high C turnover in the rhizosphere reduced shoot growth of D5/23 inoculated plants, with no effect on shoot growth of Ps I A12 inoculated plants. A separation of labeled compounds in roots and rhizodeposition revealed that neutral substances (sugars) constituted the largest fraction. The relative fractions of sugars, amino acids and organic acids in roots and rhizodeposition suggest that amino acid exudation was particularly stimulated by bacterial inoculation and that turnover of this substance group is high in the rhizosphere.

Key words

bacteria inoculation maize photosynthesis rhizodeposition rhizosphere 


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Copyright information

© Kluwer Academic Publishers 2004

Authors and Affiliations

  1. 1.Institut für Agrikulturchemie der Georg-August-Universität GöttingenGöttingenGermany
  2. 2.Institut für Bodenkunde und Pflanzenernährung der Martin-Luther-Universität Halle-WittenbergHalle/SaaleGermany

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