Effects of elevated CO₂ concentration on rhizosphere soil microbes under Pinus koraiensis and Pinus sylvestriformis seedlings

The study showed that under Pinus sylvestriformis seedlings, the amount of rhizosphere soil bacteria, but not fungi and actinomyces, increased significantly (P≤0.001) with CO₂ enrichment (700 and 500 μmol·mol^-1), and the same (P≤0.001) was under Pinus koraiensis seedlings, with the exceptions of 700 μmol CO₂·mol^-1 in August and 500 μmol CO₂·mol^-1 in July, compared to the ambient chamber and the ambient in each month. No significant effect of elevated CO₂ was found on the amount of rhizosphere soil fungi except in September (P ≤0.001), and the response of actinomyces to elevated CO₂ was also insignificant.