References

Mycorrhizosphere: Strategies and Functions 217
3
Evolution of the Rhizosphere
Plants surely encountered microorganisms in primordial soil as they moved
from aquatic to terrestrial environments (Fig. 3). Geochemical evidence for
microorganisms exists from 2600 million years ago (m.y.a.) and bacterial
fossils dating back 1200 m.y.a. are known (Horodyski and Knauth 1994;
Watanabe et al. 2000). Although true roots with vascular tissue appeared
Fig. 3. Bacterial energy channels representing fast slow cycles. (Modified after Moore et al.
2003)