Table 1.

Growth parameters, including shoot and root dry weight (DW), shoot height, net photosynthetic rate (Pn), and photochemical efficiency (Fv/Fm) of perennial ryegrass inoculated with/without the AM fungus Rhizophagus irregularis under cold stress and after melatonin application.

Treatments		Shoot DW (g plant−1)	Root DW (g plant−1)	Shoot height (cm)	Pn	Fv/Fm
Melatonin	NM-CK	1.81 ± 0.14bc	0.41 ± 0.04bc	15.52 ± 0.04b	11.33 ± 1.04a	0.85 ± 0.04a
	NM-CS	1.02 ± 0.12e	0.21 ± 0.03e	14.16 ± 0.04e	7.26 ± 0.74c	0.53 ± 0.02c
	AM-CK	2.19 ± 0.21a	0.59 ± 0.04a	17.12 ± 0.04a	11.50 ± 1.12a	0.83 ± 0.04a
	AM-CS	1.17 ± 0.17d	0.28 ± 0.03d	14.82 ± 0.04d	8.57 ± 0.71b	0.66 ± 0.02b
Non-melatonin	NM-CK	1.71 ± 0.14c	0.34 ± 0.04c	15.13 ± 0.04c	10.56 ± 0.81a	0.78 ± 0.04a
	NM-CS	0.73 ± 0.12f	0.16 ± 0.02f	13.17 ± 0.04f	6.06 ± 0.54d	0.44 ± 0.03d
	AM-CK	1.91 ± 0.18b	0.51 ± 0.03b	15.97 ± 0.04b	11.02 ± 0.72a	0.83 ± 0.06a
	AM-CS	0.91 ± 0.16e	0.23 ± 0.03de	14.07 ± 0.04e	7.51 ± 0.61c	0.56 ± 0.04c
ANOVA
CS		**	**	**	**	**
AM		**	**	*	*	*
MT		***	**	*	*	*
CS × AM × MT		*	*	ns	ns	ns

Difference in various growth parameters and comparative analysis. The data are the means ± standard deviation (n = 4). AM, AM inoculation; NM, non-AM inoculation; CK, optimal temperature condition; CS, cold stress. Different letters means significantly different based on p < 0.05. “*,” “**,” “***” indicate significant differences at p < 0.05, p < 0.01, and p < 0.001, respectively, and “ns” represents no significant difference. MT, melatonin application.