. 2021 Sep 16;12:637783. doi: 10.3389/fpls.2021.637783

Table 3.

Impacts of nano-silicon dioxide (nano-SiO₂) foliar application on the proline content (Pro, μmol g⁻¹ DW), soluble sugars (SSu, mg g⁻¹ DW), peroxidase activity (POD, unit mg⁻¹ protein), catalase activity (CAT, unit mg⁻¹ protein), superoxide dismutase activity (SOD, unit mg⁻¹ protein), ascorbic acid (AsA, μmol g⁻¹ DW), glutathione (GsH, μmol g⁻¹ FW), superoxide radical ( $O_{2}^{\cdot -}$ , A580 g⁻¹ FW), hydrogen peroxide (H₂O₂, μmol g⁻¹ FW), and α-tocopherol (α-TOC, μmol g⁻¹ DW) of well-watered and drought-stressed faba beans (Vicia faba) over two growing seasons (2019 and 2020).

Studied factor		Pro	SSu	POD	CAT	SOD	AsA	GsH	$O_{2}^{\cdot -}$	H₂O₂	α-TOC
Irrigation
	Well-watered	66.76^b	23.38^b	78.20^b	0.50^b	42.22^b	1.36^b	0.33^b	0.41^b	4.28^b	1.58^b
	Droughted	177.4^a	53.40^a	137.5^a	0.85^a	75.45^a	2.94^a	0.49^a	0.59^a	12.14^a	3.63^a
Foliar
	Control (tap water)	116.5^d	33.92^d	103.8^d	0.61^d	55.51^d	2.07^d	0.39^c	0.55^a	10.55^a	2.45^c
	0.5 mM nano-SiO₂ (T1)	121.4^c	36.91^c	105.8^c	0.65^c	57.75^c	2.11^c	0.41^b	0.51^b	8.19^b	2.59^b
	1 mM nano-SiO₂ (T2)	123.2^b	40.58^b	109.7^b	0.69^b	59.89^b	2.17^b	0.41^b	0.48^c	7.39^c	2.65^b
	1.5 mM nano-SiO₂ (T3)	127.2^a	42.13^a	112.0^a	0.74^a	62.19^a	2.24^a	0.44^a	0.46^d	6.71^d	2.72^a
Interaction
Well-watered	Control	61.47^g	20.23^f	75.21^f	0.44^h	39.91^g	1.28^f	0.31^d	0.44^e	5.04^e	1.44^f
	T1	66.99^f	22.20^e	77.77^e	0.47^g	41.47^fg	1.33^f	0.33^c	0.42^e	4.45^f	1.57^e
	T2	67.35^f	24.80^d	79.22^de	0.51^f	43.03^ef	1.38^e	0.34^c	0.39^f	3.98^fg	1.63^de
	T3	71.21^e	26.27^d	80.60^d	0.56^e	44.46^e	1.45^d	0.35^c	0.37^f	3.64^g	1.67^d
Drought stress	Control	171.5^d	47.61^c	132.4^c	0.78^d	71.11^d	2.86^c	0.47^b	0.65^a	16.06^a	3.46^c
	T1	175.9^c	51.61^b	133.9^c	0.83^c	74.02^c	2.90^c	0.48^b	0.59^b	11.93^b	3.61^b
	T2	179.1^b	56.37^a	140.3^b	0.86^b	76.74^b	2.96^b	0.49^b	0.57^c	10.79^c	3.67^b
	T3	183.1^a	58.00^a	143.5^a	0.91^a	79.92^a	3.03^a	0.54^a	0.54^d	9.79^d	3.77^a
ANOVA	DF
Irrigation (I)	1	0.0001	0.0003	<0.001	0.0001	0.0002	0.0006	0.0013	0.0008	0.0003	0.006
Foliar (F)	3	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001
I × F	3	0.024	0.009	0.0004	0.048	0.009	0.049	0.007	0.014	<0.001	0.045

Means followed by the same letters under the same factor are not significantly different by least significant difference at p ≤ 0.05.