Castasterone assisted accumulation of polyphenols and antioxidant to increase tolerance of B. juncea plants towards copper toxicity

Figures & data

Table 1. Effect of Cu and castasterone on ROS indicators (superoxide anion and hydrogen peroxide content), photosynthetic pigments (chlorophyll a, b, total chlorophyll and carotenoids content) and anthocyanin content in 60 days old B. juncea plants

Treatments		Superoxide anion radical content (μg g^−1 FW)	Hydrogen peroxide content (μmol g^−1 FW)	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)	Anthocyanin content (μg g^−1 FW)
Cu (mM)	CS (M)
0	0	6.74 ± 0.31	1.23 ± 0.03	1.76 ± 0.06	0.64 ± 0.04	2.38 ± 0.04	0.047 ± 0.001	5.25 ± 0.06
0.25	0	7.84 ± 0.81	1.36 ± 0.05	1.49 ± 0.05	0.55 ± 0.02	2.02 ± 0.06	0.070 ± 0.010	5.82 ± 0.01
0.50	0	8.03 ± 0.43	1.81 ± 0.05	1.38 ± 0.08	0.52 ± 0.07	1.89 ± 0.07	0.068 ± 0.004	6.50 ± 0.98
0.75	0	9.87 ± 0.19	2.07 ± 0.6	1.33 ± 0.06	0.51 ± 0.06	1.83 ± 0.04	0.064 ± 0.005	6.09 ± 0.06
0	10^−11	6.63 ± 0.41	1.10 ± 0.03	1.75 ± 0.09	0.57 ± 0.01	2.31 ± 0.08	0.084 ± 0.006	5.47 ± 0.07
0	10^−9	6.60 ± 0.27	1.18 ± 0.06	1.60 ± 0.15	0.68 ± 0.01	2.26 ± 0.01	0.071 ± 0.003	5.43 ± 0.06
0	10^−7	6.84 ± 0.16	1.15 ± 0.02	1.72 ± 0.09	0.63 ± 0.08	2.33 ± 0.08	0.072 ± 0.006	6.13 ± 1.04
0.25	10^−11	7.15 ± 0.48	1.30 ± 0.11	1.59 ± 0.07	0.57 ± 0.10	2.15 ± 0.07	0.070 ± 0.012	7.55 ± 0.10
0.25	10^−9	7.13 ± 0.15	1.21 ± 0.10	1.64 ± 0.05	0.60 ± 0.03	2.22 ± 0.08	0.075 ± 0.001	7.63 ± 0.08
0.25	10^−7	6.95 ± 0.29	1.22 ± 0.02	1.63 ± 0.03	0.62 ± 0.08	2.23 ± 0.05	0.072 ± 0.002	7.78 ± 0.08
0.50	10^−11	7.63 ± 0.56	1.80 ± 0.07	1.51 ± 0.04	0.55 ± 0.01	2.05 ± 0.03	0.071 ± 0.002	9.54 ± 0.09
0.50	10^−9	7.89 ± 0.48	1.65 ± 0.07	1.50 ± 0.06	0.55 ± 0.02	2.03 ± 0.05	0.075 ± 0.007	9.16 ± 0.98
0.50	10^−7	7.71 ± 0.90	1.75 ± 0.06	1.64 ± 0.01	0.60 ± 0.05	2.22 ± 0.04	0.077 ± 0.010	9.14 ± 0.99
0.75	10^−11	7.65 ± 0.05	1.83 ± 0.08	1.43 ± 0.05	0.51 ± 0.06	1.93 ± 0.09	0.066 ± 0.007	11.53 ± 0.09
0.75	10^−9	9.24 ± 0.13	1.82 ± 0.05	1.41 ± 0.05	0.52 ± 0.04	1.92 ± 0.08	0.068 ± 0.003	11.59 ± 0.06
0.75	10^−7	8.47 ± 0.22	1.89 ± 0.07	1.42 ± 0.03	0.53 ± 0.04	1.93 ± 0.06	0.070 ± 0.001	11.68 ± 0.07
F-ratio (Cu) df 3,32		51.43^**	399.42^**	42.74^**	6.01^**	97.89^**	8.24^**	186.64^**
F-ratio (CS) df 3,32		8.55^**	13.21^**	5.75^**	1.34	12.07^**	0.073	83.19^**
F-ratio (Cu × CS) df 9,32		3.16^**	2.42^*	2.95^*	0.49	4.76^**	3.24^*	14.14^**
HSD (p < 0.05)		1.310	0.192	0.209	0.200	0.192	0.019	1.521

Note: Data represent the mean ± SD of three replicates.

^* p < 0.05.

^** p < 0.01.

Figure 1. Effect of Cu and castasterone on accumulation of superoxide anion radical in 60 days old B. juncea plants.

Figure 2. Effect of Cu and castasterone on gas exchange parameters (intercellular CO₂ concentration, photosynthetic rate, stomatal conductance and transpiration rate) in 60 days old B. juncea plants.

Table 2. Effect of Cu and castasterone on specific activities of enzymes (CAT, POD, SOD, APOX, DHAR and PPO) in 60 days old B. juncea plants

Treatments		Specific activity (UA mg g^−1 FW)
Cu (mM)	CS (M)	CAT	POD	SOD	APOX	DHAR	PPO
0	0	2.62 ± 0.13	62.31 ± 3.99	1.60 ± 0.17	114.32 ± 9.52	22.87 ± 1.95	15.58 ± 0.35
0.25	0	3.97 ± 0.17	76.97 ± 6.27	2.68 ± 0.14	178.29 ± 4.69	36.39 ± 0.72	15.25 ± 0.66
0.50	0	4.70 ± 0.05	88.08 ± 6.15	3.25 ± 0.15	246.48 ± 3.84	41.45 ± 2.36	15.47 ± 0.78
0.75	0	5.46 ± 0.16	110.25 ± 3.77	3.55 ± 0.14	252.52 ± 2.66	57.30 ± 2.07	14.89 ± 0.90
0	10^−11	2.49 ± 0.10	61.42 ± 6.15	1.69 ± 0.06	117.17 ± 5.35	17.06 ± 2.67	18.30 ± 0.44
0	10^−9	2.58 ± 0.03	61.70 ± 2.39	1.64 ± 0.13	118.29 ± 1.58	22.43 ± 4.00	19.55 ± 0.62
0	10^−7	2.63 ± 0.09	65.36 ± 2.54	1.70 ± 0.18	114.56 ± 4.10	19.45 ± 2.84	20.02 ± 0.58
0.25	10^−11	4.48 ± 0.12	91.17 ± 8.80	2.97 ± 0.12	172.81 ± 5.42	38.41 ± 2.68	21.57 ± 0.81
0.25	10^−9	4.55 ± 0.14	105.13 ± 2.47	3.05 ± 0.16	193.08 ± 3.86	39.50 ± 0.77	21.97 ± 1.11
0.25	10^−7	4.59 ± 0.07	110.61 ± 4.46	3.29 ± 0.14	206.81 ± 4.83	39.28 ± 3.20	23.51 ± 0.45
0.50	10^−11	5.48 ± 0.17	115.89 ± 4.27	3.78 ± 0.19	252.52 ± 3.97	46.36 ± 108	26.12 ± 1.04
0.50	10^−9	5.47 ± 0.13	108.96 ± 2.19	3.82 ± 0.07	256.18 ± 2.97	45.62 ± 1.08	24.59 ± 0.90
0.50	10^−7	5.73 ± 0.13	110.74 ± 0.88	3.79 ± 0.07	232.97 ± 7.50	50.81 ± 1.99	29.02 ± 0.85
0.75	10^−11	5.77 ± 0.47	156.87 ± 3.48	3.82 ± 0.16	264.90 ± 5.98	58.37 ± 2.30	32.27 ± 1.81
0.75	10^−9	6.12 ± 0.31	153.02 ± 5.16	4.03 ± 0.15	251.17 ± 13.56	60.36 ± 2.55	34.04 ± 1.40
0.75	10^−7	5.96 ± 0.17	149.32 ± 1.75	4.04 ± 0.13	240.71 ± 8.52	59.60 ± 1.97	34.84 ± 1.41
F-ratio (Cu) df 3,32		739.22^**	210.54^**	599.16^**	407.82^**	558.05^**	696.20^**
F-ratio (CS) df 3,32		21.49^**	26.39^**	21.86^**	0.96	4.13^**	21.87^**
F-ratio (Cu × CS) df 9,32		3.84^**	5.049^**	2.37^*	3.38^**	3.29^**	5.28^**
HSD (p < 0.05)		0.553	23.727	0.428	33.06	7.14	2.916

Note: Data represent the mean ± SD of three replicates.

^* p < 0.05.

^** p < 0.01.

Figure 3. Effect of Cu and castasterone on protein content, sugar content, total phenolic and flavonoids content in 60 days old B. juncea plants.

Table 3. Effect of Cu and castasterone on contents of various polyphenols (μg g⁻¹) in 60 days old B. juncea plants

Polyphenol detected	Control	10^−7 M CS	0.50 mM Cu	0.50 mM Cu +10^−7 M CS
Catechin	nd	nd	32.348	161.128
Chlorogenic acid	96.824	108.236	91.516	63.064
Epicatechin	nd	nd	32.94	48.188
Caffeic acid	509.832	443.156	482.524	416.696
Coumaric acid	0.6	0.3	5.14	0.824
Rutin	37.9	31.548	44.676	55.04
Quercetin	2.524	0.832	nd	nd
Umbelliferone	nd	1.544	47.752	7.436
Ellagic acid	61.248	87.732	41.288	338.328
Kaempferol	nd	22.832	28.584	42.592
Tert-butyl hydroquinone	nd	nd	1.332	nd
Total content	708.928	696.18	808.1	1,133.296

Note: nd—not detected.