Table 3. Gene expression stability of the nine candidate reference genes under different conditions calculated by NormFinder.

Total		Developmental stages		Biotic stress		Drought stress		Salinity stress		Cold stress		Heat stress
Gene	NF	Gene	NF	Gene	NF	Gene	NF	Gene	NF	Gene	NF	Gene	NF
TIP41	0.382	TIP41	0.158	CLA	0.058	CYP	0.117	TIP41	0.054	SAND	0.052	CYP	0.073
EF1	0.413	ACT	0.268	SAND	0.073	18S rRNA	0.139	EF1	0.073	CYP	0.090	TIP41	0.164
BHLH	0.436	EF1	0.269	ACT	0.096	GAPDH	0.145	CLA	0.074	GAPDH	0.115	EF1	0.206
SAND	0.469	SAND	0.331	EF1	0.154	TIP41	0.177	GAPDH	0.083	TIP41	0.173	CLA	0.240
GAPDH	0.483	GAPDH	0.414	BHLH	0.215	BHLH	0.199	BHLH	0.092	EF1	0.329	GAPDH	0.282
CLA	0.657	18S rRNA	0.470	GAPDH	0.218	SAND	0.258	SAND	0.270	CLA	0.348	ACT	0.315
ACT	0.768	CLA	0.620	TIP41	0.353	EF1	0.265	CYP	0.418	ACT	0.349	SAND	0.362
18S rRNA	1.068	BHLH	0.915	CYP	0.419	ACT	0.311	18S rRNA	0.437	BHLH	0.383	BHLH	0.455
CYP	1.085	CYP	1.789	18S rRNA	0.543	CLA	0.333	ACT	0.478	18S rRNA	0.385	18S rRNA	0.717

Note:

A lower normalization factor (NF) value indicates higher stability of the gene.