To examine the effects of different nitrogen sources (asparagine,
phenylalanine and (NH4)2SO4), sugars (glucose, sucrose and fructose)
and Fe3+ ion on biocontrol activity of P. guilliermondii strain
M8 against B. cinerea, AJM was used throughout the experiment.
AJM was prepared as described in Section 2.3. The yeast (100 ll
containing 5 109 cells ml1) and pathogen spore suspensions
(100 ll containing 5 106 conidia ml1) were added to the test
tubes (18 150 mm) containing 4.8 ml of AJM supplemented or
not with nitrogen sources, sugars and Fe3+ ion. The nitrogen and
sugars were used at final concentrations of 0.5% and 1.0%, and
Fe3+ ion was supplemented as FeCl37H2O at final concentrations
of 0.1 mM and 0.5 mM. The inoculated tubes were incubated at
25 C for 20 h on a rotary shaker at 200 rpm. Then, 100 spores were
randomly selected out from each tube and their germination was
evaluated. Three replications were included for each treatment
and the experiment was repeated twice.