Table 1.

Effect of foliar application of putrescine on concentrations of chlorophylls (mg 100 g⁻¹ FW) in younger leaves of the cauliflower cv. Moonshine at different ration of NO₃⁻/NH₄⁺ and temperatures.

Temperature	NO3−/NH4+		Chl a	Chl b	Chl a + Chl b	Chl a/Chl b
Ambient temperature	100/0	Without Put	43.69 ± 1.14 ab	58.37 ± 6.05 b	112.07 ± 7.05 de	0.92 ± 0.19 d
		With Put	53.13 ± 0.55 ab	64.71 ± 8.63 a	117.84 ± 9.00 bc	0.81 ± 0.06 e
	80/20	Without Put	54.03 ± 0.61 ab	60.13 ± 4.38 b	114.16 ± 4.89 cd	0.90 ± 0.14 d
		With Put	54.43 ± 0.23 ab	65.75 ± 8.67 a	120.18 ±8.73 ab	0.83 ± 0.03 e
	50/50	Without Put	54.66 ± 0.65 a	60.91 ± 6.57 b	115.57 ± 7.08 cd	0.90 ± 0.10 d
		With Put	52.03 ± 1.67 abc	74.52 ± 5.48 a	126.55 ± 7.00 a	0.70 ± 0.01 f
High temperature	100/0	Without Put	53.09 ± 1.75 ab	48.02 ± 0.22 c	101.11 ± 3.87 hi	1.11 ± 0.13 a
		With Put	52.82 ± 1.01 ab	53.20 ± 0.22 c	106.03 ± 3.12 fg	1.01 ± 0.21 b
	80/20	Without Put	54.66 ± 1.94 a	47.11 ± 0.99 c	101.78 ± 2.88 gh	1.16 ± 0.18 a
		With Put	51.11 ± 1.67 c	58.20 ± 6.06 b	109.31 ± 7.57 ef	0.87 ± 0.06 d
	50/50	Without Put	53.20 ± 2.41 ab	49.57 ± 2.64 c	102.77 ± 4.95 gh	1.07 ± 0.13 a
		With Put	53.70 ± 1.95 ab	56.62 ± 1.90 b	110.39 ± 3.78 ef	0.94 ± 0.11 c
Main effects
Temperature (T)			***	***	***	***
Putrescine (Put)			***	***	***	***
Nitrate/ammonia (NO3−/NH4+)			*	***	ns	*
T X Put			ns	ns	ns	ns
T X NO3−/NH4+			ns	ns	ns	ns
Put X NO3−/NH4			ns	ns	ns	ns
T X Put X NO3−/NH4+			*	ns	ns	*

Different small letters within a column indicate significant differences among different treatments of putrescine treatments with different NO₃⁻/NH₄⁺ ratio and temperatures (p = 0.05. Tukey test). n = 5, ±S.E. Analysis of variance: ns. not significant; * p ≤ 0.05; *** p ≤ 0.001.