Table 5.

Effect of mycorrhizal inoculation (AMF), date of inoculation (days after seeding), and nitrogen (N) form on chalcone synthase (CHS1), flavonol synthase (FLS1), and phenylalanine ammonia lyase (PAL1) gene expression (relative based on CT values) of onion bulbs (cv. Stuttgarter Riesen) in a three-factorial ANOVA based on an orthogonal design with three replications. Values represent gene transcript abundance of CHS1, FLS1, and PAL1 genes normalized to the reference gene ALL ITS1 derived of three independent repetitions. Means ± standard deviation followed by the same letter do not differ significantly according to Duncan’s multiple range test. Probability levels written in italics indicate significant differences at a significance level of α = 0.05

AMF (v/v %)	Date (days)	N form	CHS1	FLS1	PAL1
0			2.83 ± 0.94	3.83 ± 1.79	2.43 ± 0.98
0.3			3.61 ± 1.06	4.54 ± 2.07	2.89 ± 1.76
3.0			2.95 ± 1.37	4.05 ± 1.23	2.44 ± 1.33
	0		2.76 ± 1.41	3.96 ± 2.01	2.21 ± 1.16
	65		3.51 ± 1.6	4.32 ± 1.69	2.97 ± 1.26
		NO3 –a	3.32 ± 1.26	4.51 ± 1.67	2.65 ± 1.22
		NH4 + b	2.95 ± 1.32	3.78 ± 1.69	2.53 ± 1.23
0	0	NO3 −	2.73 ± 1.2 bc	4.86 ± 1.09abc	2.09 ± 0.93 b
0.3			4.56 ± 0.71 a	5.24 ± 1.5 a	4.16 ± 0.31 a
3.0			2.65 ± 0.7 b	3.40 ± 0.69 ab	2.09 ± 0.68 b
0	0	NH4 +	2.92 ± 0.44 b	2.81 ± 0.43 b	2.38 ± 0.71 b
0.3			2.67 ± 1.68 b	3.85 ± 1.36 ab	−0.62 ± 3.37 c
3.0			3.26 ± 1.84 ab	4.70 ± 1.36 ab	3.15 ± 2.09 ab
0	65	NO3 −			2.30 ± 0.71 b
0.3					3.39 ± 0.9 ab
3.0					1.84 ± 0.77 b
0	65	NH4 +			2.94 ± 0.23 ab
0.3					4.64 ± 0.64 a
3.0					2.69 ± 1.68 b
Source of variation			Probability level
AMF			0.237	0.528	0.710
Date			0.065	0.498	0.147
N form			0.347	0.177	0.821
AMF × Date			0.454	0.165	0.126
AMF × N form			0.035	0.030	0.092
Date × N form			0.517	0.690	0.054
AMF × Date × N form			0.063	0.202	0.039

^aNO₃ ⁻ predominant = 95% NO₃ ⁻/5% NH₄ ⁺

^bNH₄ ⁺ predominant = 25% NO₃ ⁻/75% NH₄ ⁺

^cOnly the significant results of the AMF × N form interaction are presented averaged over the dates