Modulation of growth and oxidative stress by seed priming with salicylic acid in Zea mays L. under lead stress

Figures & data

Figure 1. Effect of seed pretreatment with SA on Pb content (non-stressed plants not detected) of maize plants under lead stress conditions (Mean ± SE, n = 3), P ≤ 0.05.

Table 1. Effect of seed pretreatment with salicylic acid on Pb content, growth parameters and total chlorophyll content of maize plants under lead stress conditions (Mean ± SE, n = 3).

Parameters	Tissue	Control	SA (0.5 mM)	Pb (2.5 mM)	SA + Pb
Length (cm)	Shoot Root	33.00^bc ± 1.00 32.33^ab ± 0.88	37.00^a ± 0.57 34.50^a ± 1.32	20.33^d ± 0.66 19.50^c ± 0.76	34.00^b ± 0.57 31.16^b ± 0.72
Fresh weight (g/plant)	Shoot Root	0.81^bc ± 0.09 0.82^b ± 0.09	1.27^a ± 0.09 1.10^a ± 0.11	0.55^c ± 0.02 0.43^c ± 0.02	0.95^b ± 0.09 0.90^ab ± 0.10
Dry weight (g/plant)	Shoot Root	0.07^b ± 0.004 0.06^ab ± 0.007	0.11^a ± 0.02 0.08^a ± 0.007	0.06^b ± 0.003 0.05^b ± 0.008	0.08^ab ± 0.009 0.07^ab ± 0.008
Total chlorophyll (mg/g FW)		1.43^a ± 0.04	1.51^a ± 0.10	0.91^c ± 0.02	1.20^b ± 0.07

Note: Values within rows followed by the same letter(s) are not significantly different at (P ≤ .05) level.

Table 2. Effect of seed pretreatment with salicylic acid on proline, NPT, PT, GSH and AsA contents of maize plants under lead stress conditions (Mean  ±  SE, n = 3).

Parameters	Tissue	Control	SA (0.5 mM)	Pb (2.5 mM)	SA + Pb
Proline (µmol/g FW)	Shoot Root	75.26^c ± 4.06 131.46^c ± 3.79	124.30^b ± 6.20 156.55^bc ± 6.20	165.16^a ± 1.24 215.34^a ± 11.53	113.54^b ± 5.68 171.61^b ± 8.95
NPT (µmol/g FW)	Shoot Root	0.37^a ± 0.02 0.19^c ± 0.01	0.35^ab ± 0.02 0.18^c ± 0.02	0.27^b ± 0.03 0.24^bc ± 0.02	0.40^a ± 0.02 0.35^a ± 0.02
PT (µmol/g FW)	Shoot Root	0.40^a ± 0.05 0.38^a ± 0.01	0.44^a ± 0.01 0.39^a ± 0.02	0.25^b ± 0.02 0.22^b ± 0.03	0.39^a ± 0.05 0.34^a ± 0.03
GSH (µmol/g FW)	Shoot Root	0.20^b ± 0.008 0.09^c ± 0.02	0.25^ab ± 0.03 0.20^b ± 0.02	0.11^c ± 0.01 0.19^b ± 0.03	0.33^a ± 0.03 0.30^a ± 0.03
AsA (µmol/g FW)	Shoot Root	7.14^b ± 0.13 5.43^a ± 0.06	7.90^ab ± 0.42 6.30^a ± 0.53	7.79^ab ± 0.26 4.12^b ± 0.26	8.81^a ± 0.26 6.08^a ± 0.10

Note: Values within rows followed by the same letter(s) are not significantly different at (P ≤ .05) level.

Table 3. Effect of seed pretreatment with salicylic acid on MDA and H₂O₂ content and antioxidants activities of maize plants under lead stress conditions (Mean  ±  SE, n = 3).

Parameters	Tissue	Control	SA (0.5 mM)	Pb (2.5 mM)	SA + Pb
MDA (µmol/g FW)	Shoot Root	1.09^cd ± 0.04 1.00^d ± 0.05	0.97^d ± 0.04 0.91^d ± 0.04	1.74^a ± 0.05 1.83^a ± 0.06	1.31^bc ± 0.10 1.39^c ± 0.03
H2O2 (µmol/g FW)	Shoot Root	0.74^c ± 0.06 0.38^c ± 0.07	0.75^c ± 0.04 0.35^c ± 0.08	2.71^a ± 0.08 3.50^a ± 0.27	1.88^b ± 0.05 2.32^b ± 0.16
APX activity (Unit/mg protein in 150 µl extract)	Shoot Root	32.39^b ± 3.87 32.36^e ± 4.67	41.50^ab ± 6.50 51.78^d ± 5.10	27.86^b ± 5.27 76.33^c ± 5.61	53.01^a ± 2.68 240.84^a ± 3.48
CAT activity (Unit/mg protein in 100 µl extract)	Shoot Root	35.25^b ± 1.56 20.25^c ± 1.56	38.75^b ± 2.64 18.25^c ± 3.25	75.25^a ± 2.38 33.12^b ± 2.60	92.50^a ± 8.05 41.65^a ± 3.00
GPX activity (Unit/mg protein in 20 µl extract)	Shoot Root	54.41^ab ± 3.05 71.13^a ± 4.39	66.66^a ± 5.65 78.37^a ± 2.48	40.49^b ± 4.51 75.72^a ± 4.93	68.92^a ± 7.42 82.31^a ± 4.12
GR activity (Unit/mg protein in 300 µl extract)	Shoot Root	2.39^b ± 0.40 8.76^b ± 1.53	2.98^b ± 0.43 10.18^b ± 1.44	4.38^ab ± 0.90 13.13^b ± 1.19	5.37^a ± 0.74 17.74^a ± 1.28

Note: Values within rows followed by the same letter(s) are not significantly different at (P ≤ .05) level.

Figure 2. Effect of seed pretreatment with SA on H₂S content of maize plants under lead stress (Mean ± SE, n = 3), P ≤ 0.05.

Figure 3. Effect of seed pretreatment with SA on L-DES activity of maize plants under lead stress conditions (Mean ± SE, n = 3), P ≤ 0.05.