Beneficial effects of silicon nutrition in alleviating salinity stress in hydroponically grown canola, Brassica napus L., plants

Figures & data

Table 1 Effect of salinity (control versus 150 mmol L−1 NaCl) on the fresh and dry weights of canola plants grown for 25 days with or without 2 mmol L−1 supplementary silicon as Na2SiO3 in the nutrient solution

Treatments	Fresh weight (g plant^−1)			Dry weight (g plant^−1)
	Shoot	Root	Total	Shoot	Root	Total
Control	81.18 ± 5.31a	15.99 ± 0.65a	97.18 ± 5.68a	5.94 ± 0.55a	1.16 ± 0.11a	7.10 ± 0.65a
Si	77.69 ± 4.96a	13.73 ± 0.42ab	91.43 ± 5.35a	5.40 ± 0.28ab	1.16 ± 0.07a	6.42 ± 0.34a
NaCl	25.99 ± 6.39c	6.92 ± 1.28c	32.91 ± 7.64c	1.8 ± 0.51c	0.40 ± 0.07b	2.27 ± 0.57c
Si + NaCl	52.56 ± 4.94b	12.04 ± 0.85b	64.61 ± 4.92b	3.98 ± 0.35b	0.61 ± 0.05b	4.59 ± 0.37b
LSD 0.05	17.73	2.82	19.53	1.42	0.253	1.65
Data are mean ± standard error (n = 4). Means followed by the same letter within each column are not significantly different according to a least significant difference (LSD) test (P < 0.05).

Table 2 Na+, K+ and Si concentrations in the roots and shoots of canola plants grown for 25 days at 150 mmol L−1 NaCl with or without 2 mmol L−1 supplementary silicon as Na2SiO3 in the nutrient solution

Treatments	Na^+ (mg g^−1 dry weight)		K^+ (mg g^−1 dry weight)		Si (mg g^−1 dry weight)
	Shoot	Root	Shoot	Root	Shoot	Root
Control	2.86 ± 1.03c	1.19 ± 0.78b	49.1 ± 2.13a	53.8 ± 2.11a	0.22 ± 0.17b	0.61 ± 0.18c
Si	2.84 ± 1.91c	1.84 ± 0.74b	44.5 ± 2.04a	55.7 ± 4.54a	0.68 ± 0.11a	1.33 ± 0.21a
NaCl	35.01 ± 1.37a	18.28 ± 1.55 a	14.3 ± 0.59b	24.8 ± 3.20b	0.38 ± 0.01b	0.55 ± 0.12c
Si + NaCl	15.13 ± 0.33b	15.35 ± 0.57 a	16.5 ± 0.98b	24.4 ± 4.95b	0.56 ± 0.04a	0.91 ± 0.16b
LSD 0.05	5.55	3.23	5.17	12.63	0.20	0.29
Data are mean ± standard error (n = 4). Means followed by the same letter within each column are not significantly different according to a least significant difference (LSD) test (P < 0.05).

Figure 1 Effect of salinity (control versus 150 mmol L−1 NaCl) on the malondialdehyde concentrations as a measure of lipid peroxidation in the (a) shoots and (b) roots of canola plants grown for 25 days with or without supplementary silicon. Error bars represent the standard error. FW, fresh weight. Different small letters on histograms represent statistically significant differences at P < 0.05.

Figure 2 Effect of salinity (control versus 150 mmol L−1 NaCl) on the activity of (a,b) catalase, (c,d) perosidase, (e,f) cell wall perosidase and (g,h) polyphenol oxidase in the roots (a,c,e,g) and shoots (b,d,f,h) of canola plants grown for 25 days with or without supplementary silicon. Error bars represent the standard error. Different small letters on histograms represent statistically significant differences at P < 0.05.

Figure 3 (a,b) Phenolics and (c,d) lignin contents in the roots (b,d) and shoots (a,c) of canola plants grown for 25 days under salinity with or without supplementary silicon. Error bars represent the standard error. DW, dry weight. Different small letters on histograms represent statistically significant differences at P < 0.05.

Figure 4 Soluble protein contents of the (a) shoots and (b) roots of canola plants grown for 25 days under salinity with or without supplementary silicon. Error bars represent the standard error. DW, dry weight. Different small letters on histograms represent statistically significant differences at P < 0.05.

Figure 5 Effect of salinity (control versus 150 mmol L−1 NaCl) on the (a) chlorophyll a and (b) chlorophyll b contents of canola plants grown for 25 days with or without supplementary silicon. Error bars represent the standard error. DW, dry weight. Different small letters on histograms represent statistically significant differences at P < 0.05.