Table 1.

Basic photosynthetic parameters extracted from the OJIP transient curves.

Treatment	F0	FM	FK	FJ	FI	M0
NT	0.28 ± 0.004c	1.07 ± 0.003a	0.73 ± 0.01a	0.76 ± 0.02a	0.97 ± 0.01a	2.28 ± 0.07a
NT+MLT	0.28 ± 0.006c	1.07 ± 0.005a	0.73 ± 0.004a	0.76 ± 0.01a	0.97 ± 0.012a	2.34 ± 0.09a
NA	0.29 ± 0.02 b	0.62 ± 0.06c	0.40 ± 0.02c	0.51 ± 0.02c	0.59 ± 0.05b	1.34 ± 0.089c
NA+MLT	0.30 ± 0.01b	0.67 ± 0.08c*	0.46 ± 0.04c*	0.54 ± 0.04c*	0.62 ± 0.07c	1.62 ± 0.071bc*
CA	0.33 ± 0.02 a	0.73 ± 0.02b	0.50 ± 0.01b	0.55 ± 0.01b	0.62 ± 0.03b	1.57 ± 0.009b
CA+MLT	0.35 ± 0.01a	0.84 ± 0.05b*	0.54 ± 0.03b*	0.64 ± 0.03b*	0.74 ± 0.05b*	1.82 ± 0.072b*

NT was normal temperature of 30°C. CA was cold acclimation, which Bermudagrass were treated with 4°C for 7 d and then transferred to −5°C for 8 h. NA was cold stress without acclimation, which plants were treated with −5°C for 8 h without pre-treatment with 4°C. MLT was melatonin. Independent-samples t-test was used to determine statistical differences. Different letters indicate statistical difference significance at P < 0.05 among the temperature treatments. Asterisk was significantly different after MLT treatment.