Rhizosphere and Soil Microbial Populations

Petri plates with agar media for specific types of microorganisms were inoculated with 8 individual droplets of 0.01 ml for each suspension (up to 2 suspensions per petri dish) and held for 6 days at 30°C in the dark before microorganisms were enumerated (number of positive droplets). The colony-forming units (CFU)/g root dry weight or soil dry weight were determined from tables provided by Harris and Sommers (1968). The smallest population of any microbial group that could be enumerated was 20 CFU/g of root or soil. 

2 Plant-Plant AUelopathic Interactions. Phase 1 The Laboratory 

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