The effects of foliar application of melatonin on some physiological and biochemical characteristics and expression of fatty acid desaturase gene in pistachio seedlings (Pistacia vera L.) under freezing stress

Figures & data

Table 1 Effects of exogenous application of melatonin on malondialdehyde (MDA), other aldehydes, membrane leakage and hydrogen peroxide (H₂O₂) content of pistachio seedlings exposed to freezing stress.

Freezing stress	Melatonin concentration (µM)	MDA content (nmol g^−1 FW)	Other aldehydes content (nmol g^−1 FW)	Membrane leakage (%)	H2O2 content (µmol g^−1 FW)
−	0	3.44^E	98.18^d	30.75^d	1.40^d
−	0.1	4.00^dE	98.18^d	26.88^e	2.22^bc
−	0.25	6.32^d	109.41^cd	26.17^e	2.41^b
−	0.5	9.087^c	127.79^c	30.61^d	2.93^b
+	0	23.61^a	458.21^a	77.25^a	5.128^a
+	0.1	14.97^b	173.01^b	42.00^b	2.62^b
+	0.25	9.29^c	120.79^c	36.21^c	1.60^cd
+	0.5	10.54^c	97.88^d	34.87^c	2.13^bcd

Different letters in the same column indicate significant differences according to LSD tests (p < 0.05), (−): not freezing treated seedlings, (+): freezing treated seedlings.

Table 2. Effects of exogenous application of melatonin on activities of guaicol peroxidase (GPX), catalase (CAT) and ascorbate peroxidase (APX) in pistachio seedlings exposed to freezing stress.

Freezing stress	Melatonin concentration (µM)	GPX activity (U mg^−1 protein)	CAT activity (U mg^−1 protein)	APX activity (U mg^−1 protein)
−	0	0.16^de	10.43^e	78.38^b
−	0.1	0.11^e	26.37^d	76.37^b
−	0.25	0.22^cd	10.96^e	48.79^e
−	0.5	0.19^de	13.19^e	64.11^c
+	0	0.59^a	147.46^a	111.52^a
+	0.1	0.35^b	67.81^b	58.77^cd
+	0.25	0.27^c	49.67^c	54.63^de
+	0.5	0.14^de	16.58^e	64.36^c

Different letters in the same column indicate significant differences according to LSD tests (p < 0.05), (−): not freezing treated seedlings, (+): freezing treated seedlings.

Table 3. Effects of exogenous application of melatonin on concentrations of glutathione, ascorbate, dehydroascorbate, ratio of ascorbate to dehydroascorbate and radical scavenging capacity in pistachio seedlings exposed to freezing stress.

Freezing stress	Melatonin concentration (µM)	GSH content (µmol/g FW)	Ascorbate content (mg/g FW)	Dehydroascorbate content (mg/g FW)	Ascorbate/dehydroascorbate ratio	Inhibition (%)
−	0	0.38^abc	0.39^e	1.61^cd	0.24^c	29.78^d
−	0.1	0.42^a	0.55^d	1.33^e	0.42^b	34.18^c
−	0.25	0.41^ab	0.72^bc	1.37^e	0.53^b	34.64^c
−	0.5	0.42^a	0.60^cd	1.42^de	0.43^b	39.51^ab
+	0	0.12^d	0.20^f	2.72^a	0.07^d	33.37^c
+	0.1	0.34^bc	0.79^b	2.03^b	0.39^b	38.00^b
+	0.25	0.33^c	0.85^b	1.68^c	0.51^b	39.28^ab
+	0.5	0.40^abc	1.14^a	1.61^cd	0.71^a	40.55^a

Different letters in the same column indicate significant differences according to LSD tests (p < 0.05), (−): not freezing treated seedlings, (+): freezing treated seedlings.

Table 4. Effects of exogenous application of melatonin on chlorophyll a, chlorophyll b, total chlorophyll and carotenoids content of pistachio seedlings exposed to freezing stress.

Freezing stress	Melatonin concentration (µM)	Chlorophyll a content (mg g^−1 FW)	Chlorophyll b content (mg g^−1 FW)	Total chlorophyll content (mg g^−1 FW)	Carotenoids content (mg g^−1 FW)
−	0	4.70^abc	1.03^d	5.74^cd	1.29^ab
−	0.1	4.06^d	1.23^cd	5.28^de	1.04^bc
−	0.25	4.59^bc	1.09^cd	5.67^cd	1.30^a
−	0.5	4.97^ab	1.40^bc	6.37^b	1.27^ab
+	0	4.12^d	0.68^e	4.80^e	1.08^ab
+	0.1	4.89^ab	1.98^a	6.86^a	1.09^ab
+	0.25	5.15^a	1.84^a	6.98^a	1.20^ab
+	0.5	4.40^cd	1.68^ab	6.08^b	0.82^c

Different letters in the same column indicate significant differences according to LSD tests (p < 0.05), (−): not freezing treated seedlings, (+): freezing treated seedlings.

Table 5. Effects of exogenous application of melatonin on concentrations of proline, soluble sugars, phenolic component, GABA (γ-aminobutyric acid) and activity of phenylalanine ammonia lyase (PAL) in pistachio seedlings exposed to freezing stress.

Freezing stress	Melatonin concentration (µM)	Proline content (µmol g^−1 FW)	Soluble sugars content (μmol g^−1 FW)	Total phenol content (mg/g FW)	PAL activity (U/mg protein)	GABA content (μmol g^−1 FW)
−	0	5.06^b	64.91^b	5.48^b	12.68^bc	39.08^f
−	0.1	1.28^e	44.91^c	5.00^bc	12.69^bc	41.81^c
−	0.25	2.52^d	38.41^c	5.50^bc	10.71^bcd	45.23^d
−	0.5	2.59^d	40.69^c	2.81^d	7.90^d	47.63^c
+	0	10.16^a	90.66^a	13.03^a	21.08^a	51.33^a
+	0.1	3.68^c	47.26^c	4.50^c	14.15^b	49.13^b
+	0.25	3.57^c	46.10^c	5.28^bc	13.63^bc	42.88^e
+	0.5	3.99^c	36.35^c	2.98^d	9.94^cd	38.51^f

Different letters in the same column indicate significant differences according to LSD tests (p < 0.05), (−): not freezing treated seedlings, (+): freezing treated seedlings.

Figure 1. Effects of exogenous application of melatonin on expression of fatty acid desaturase (FAD2) gene in pistachio seedlings exposed to freezing stress. Different letters indicate significant differences according to LSD tests (p < 0.05).