3.2 Responses of enzymes activity and microbial biomass to
artificial root exudates
Compared with the control, the activities of the three enzymes measured
significantly increased. The BG and XYL enzymes increased in the order
C-only > CN80 > CN10 > CN6
> Control (Fig. 3). Conversely, NAG activity decreased with
decreasing N content in the simulated root exudates on day 3, following
the order of CN 6 > CN10 > CN80 >
C-only. Increasing the BG/NAG ratio increased qCO2(R2 = 0.41, P = 0.01) and suppressed the CUE
(R2 = 0.36, P = 0.02) (Fig. 4a). Compared with
the control, MBC and MBN remarkably increased (except in CN6 and
C-only). However, there was a minor rise from day 3 to day 45 in all
treatments (Table S2). C/N ratios of the microbial biomass ranged from
3.2 to 7.8 (Fig. 4c). The MBC/MBN ratio was negatively correlated with
qCO2 (R2 = 0.29, P = 0.01) and
CUE (R2 = 0.36, P = 0.02) (Fig. 4b).