Role of bulk and Nanosized SiO₂ to overcome salt stress during Fenugreek germination (Trigonella foenum- graceum L.)

ABSTRACT

The effects of bulk and Nanosized SiO₂ on seed germination and seedling growth indices of fenugreek under salinity stress were studied in the College of Agriculture, Ferdowsi University of Mashhad, Iran, in 2013. The experimental treatments included 4 levels of salinity stress (0, 50, 100 and 150 mM), 2 concentrations of bulk (50 and 100 ppm), 2 concentrations of nanosized SiO₂ (50 and 100 ppm), and control (without any SiO₂ types). Seedling growth attributes significantly improved when bulk and nanosized SiO₂ concentrations applied singly or with different levels of salt stress. However, they significantly declined with salt application. The adverse effects of salt on shoot, root and seedling lengths were alleviated by application of 50 ppm nanosized SiO₂ treatment. Under salt stress condition, addition of 50 and 100 ppm nanosized SiO₂ to fenugreek seeds increased shoot, root and seedling dry weights as compared to bulk SiO₂ concentrations and control treatments, though 50 ppm nanosized SiO₂ was more effective than 100 ppm nanosized SiO₂ application. It was concluded that nanosized SiO₂ improves growth attributes of fenugreek and mitigate adverse effects of salt stress.

Introduction

Nanotechnology is a science that nowadays has widely application in industrial and commercial products.²⁷ Nanotechnology allows wide advances in agriculture science, such as agricultural transfer, reproductive science and technology, food wastes to energy and treatment in plants using various nanocides.¹⁰

Nanoparticles, because of their tiny size show unique characteristics. They can change physic–chemical properties compared to their bulk particles. Because of these larger surface areas, their solubility and surface reactivity was higher than their bulk particles.¹¹ However, understanding of the interaction mechanisms at the molecular level between nanoparticles and biological systems is an unknown topic.^9,16

Silicon is the second most abundant element in the earth's crust, yet its role in biology of plants has been poorly understood.⁴ Although silicon has not been listed among the essential elements for plants, but it can reach levels in plants similar to those of macro elements.⁶

Ahmed et al.⁴ recorded that silicon caused to reduce the impacts of different stresses such as salt and drought stresses, metal toxicity, diseases, various pests, radiation damage, high temperature and nutrients imbalance. Satisfactory result of silicon application against salt stress have been shown in fenugreek,²⁹ Cucumber (Cucumis sativus L.),⁶ wheat (Triticum aestivum),⁵ and Prospis jaliflora.

Lu et al.²⁵ revealed that a combination of nanoSiO₂ and TiO₂ could increase the nitrate reductase enzyme in soybean, increase its abilities of absorbing and utilizing water and fertilizer and accelerate its germination and growth. Haghighi and others¹⁹ showed that nanoSiO₂ improved germination characteristics such as germination rate, root length and dry weight in tomato under 25 mM salinity.

Salinity is one of the most important abiotic stresses for plant growth in most of the world especially in arid and semiarid area.¹⁶ Salinity has osmotic (cell hydration) and toxic (ion accumulation) impact on plants.³¹

A few studies have been done on the effects of nanoparticles on crops particularly on medicinal plants. In this research, we studied the either negative or positive effects of different concentrations of bulk and nanosized SiO₂ on seed germination and seedling growth of fenugreek under salt stress.

Materials and methods

Nanosized SiO₂ powder was as nano silicon oxide that was supplied by TECNAN (Navarrean Nanoproducts Technology) Company. Specific surface area of nanosized SiO₂, Average primary particle size, Purity and True density were 180–270 m² g⁻¹, 10–15 nm, >99.9% and 2.2 g cc⁻¹, respectively. Also, Pore volume and Average pore size were 0.549 cm³g⁻¹ and 110.13 Å, respectively. The size of nanoSiO₂ (Fig. 1) were determined by Transmission Electron Microscope (TEM) in University of Alicante and equipment was used JEOL, Mod. JEM-2010. Bulk SiO₂ powder was taken from Chemistry Laboratory of Ferdowsi University of Mashhad, Iran with 99% purity, and >230 mesh particle size. A randomized completely design with 3 replications was used for different concentrations of bulk and nanosized SiO₂ under salt stress on fenugreek germination and seedling growth. The experimental treatments included 4 levels (0, 50, 100 and 150 mM) of salinity stress (NaCl), 2 concentrations (50 and 100 ppm) of bulk and 2 concentrations (50 and 100 ppm) of nanosized SiO₂ and control treatment (without any SiO₂ types).

Figure 1.

Image of nanosized SiO₂ by TEM.

Seeds were surface sterilized with 0.1% mercuric chloride for 30 s and washed several times with distilled water. They were soaked in solution of different concentrations of bulk and nanosized SiO₂ for 24 h and dried by sterile paper. Twenty-five seeds were transferred into the each sterile Petri dish, and then 5 mM of each concentration of NaCl treatment was added to each Petri dish.

For the control treatment, only distilled water was added to Petri dishes. The dishes were covered with Slophan paper and were placed in incubator under 20 ± 1°C temperature and 70% humidity.

Germination tests were performed according to the rule issued by the International Seed Testing Association.²⁰

The number of germinated seeds was daily recorded for 14 d Seeds were considered as germinated when their radicle was at least 2 mm length.²⁰ After 14 days, final germination percentage and the growth parameters were determined. Mean germination time (MGT) was calculated on the basis of Matthews and Khajeh-Hosseini²⁸ as follows:

$${\displaystyle MGT=\frac{{{\displaystyle \sum }}^{}FX}{{{\displaystyle \sum }}^{}F}}$$ (1)

where F is the number of seeds newly germinated at the time of X, and X is the number of days started from sowing stage.

Seedling vigor was calculated on the basis of Vashisth and Nagarajan³⁶ as follows:

$${\displaystyle \text{Vigor}\hspace{0.17em}\text{index}\hspace{0.17em}\text{I}=\text{germination}\% \times \text{seedling}\hspace{0.17em}\text{length}}$$ (2)

$${\displaystyle \text{Vigor}\hspace{0.17em}\text{index}\hspace{0.17em}\text{I}=\text{germination}\% \times \text{seedling}\hspace{0.17em}\text{weight}}$$ (3)

Statistical analysis

Analysis of data was performed on a randomized completely designed with 3 replications using MSTAT-C software and the means compared by Duncan Multiple Range Test at 5% level.

Results and discussion

The results indicated that the germination of seed fenugreek was affected by 3 salt treatments (Tables 1 and 2). Increasing salt concentration caused reduction in germination parameters expected mean germination time (Table 3). The most mean germination time was observed at the highest level of salt concentration compared to control, while other germination parameters were decreased mainly at the highest level of salt concentration compared to control (Table 3). Ashraf and Orooj⁷ indicated that the effect of salinity on plant could be as a result of reduction osmotic potential in the medium root, nutrient deficient and also ion specific toxicity. They realized that with increasing salt concentration, growth is decreased.

Table 1.

Analysis of variance (mean of squares) of seed germination and seedling growth indices of fenugreek.

Source of Variation	Degree of freedom	MGT (day)	Germination (%)	Shoot length (mm)	Root length (mm)	Seedling length (mm)
Salt stress (a)	3	1.90**	80.55**	1976.84**	581.24**	4526.11**
Bulk and nanosized SiO2 (b)	4	0.30**	97.44**	881.28**	201.08**	1911.43**
a×b	12	0.021*	4.70ns	36.11ns	7.63ns	40.31ns
Error	40	0.009	15.10	24.03	15.66	29.10
CV%	—	7.50	4.07	10.40	12.42	6.83

In each column,

^** and

^*shows significantly different at 1 and 5% probability levels, and ns is not significantly different.

Table 2.

Analysis of variance (mean of squares) of seed germination and seedling growth indices of fenugreek.

Source of Variation	Degree of freedom	Shoot dry matter (mg)	Root dry matter (mg)	Seedling dry matter (mg)	Vigor index I (mg)	Vigor index II (mg)
Salt stress (a)	3	20.36**	1.06**	30.09**	498574.30**	345914.70**
Bulk and nanosized SiO2 (b)	4	4.04**	0.65**	8.54**	218740.20**	115627.20**
a×b	12	0.12ns	0.02ns	0.17ns	5521.98ns	1661.28ns
Error	40	0.13	0.01	0.11	2827.36	1865.64
CV%	—	5.84	11.55	4.57	7.02	6.05

In each column,

^** and

^*shows significantly different at 1 and 5% probability levels, and ns is not significantly different.

Table 3.

The effect of Salinity on germination characteristics of fenugreek.

NaCl (mM)	MGT (day)	Germination (%)	Shoot length (mm)	Root length (mm)	Seedling length (mm)	Shoot dry matter (mg)	Root dry matter (mg)	Seedling dry matter (mg)	Vigor index I (mg)	Vigor index II (mg)
0	0.96d	98.73a	57.68a	40.00a	97.67a	7.60a	1.50a	9.11a	965.59a	900.71a
50	1.12c	95.00ab	54.03a	32.96b	87.00b	6.81b	1.21b	8.03b	828.60b	764.86b
100	1.27b	94.13b	44.83b	28.93bc	73.76c	5.58c	1.04c	6.68c	694.57c	631.30c
150	1.78a	93.60b	31.93c	25.50c	57.43d	5.03d	0.88d	5.92d	539.79d	556.22d

Means in each column followed by same letters are not significantly (P < 0 .05) different according to Duncan's multiple range test.

Similar results were reported on seedlings of fenugreek, Psyllium (Plantago psyllium) and fennel (Foeniculum vulgare) in relation to effect of salinity inhibition.^16,33

All of the germination parameters were significantly affected by bulk and nanosized SiO₂ concentrations (Tables 1 and 2). Application of 50 ppm nanoSiO₂ significantly increased fenugreek seed germination from 95.50 percent in control treatment to 99.00 percent. As a general procedure, lower Mean Germination Time (MGT) is state faster seed germination. Our results indicated that the lowest MGT was in 50 ppm nanoparticle treatment (1.09 days) (Table 4). Activation of respiratory and rapid production of ATP appears to be most important metabolic events stimulate by faster seed germination.¹³ Zheng et al.³⁸ showed that significant effects of nanoTiO₂ on seed germination of spinach. They referred results to small particle size, which allowed nanomaterials to penetrate into the seed throughout the treatment period, increasing their functions during the growth period.

Table 4.

The effect of bulk and nanosized SiO₂ concentrations on germination characteristics of fenugreek.

Materials type	Concentration (ppm)	MGT (day)	Germination (%)	Shoot length (mm)	Root length (mm)	Seedling length (mm)
Bulk SiO2	50	1.24c	95.00bc	51.58b	33.70ab	85.29b
	100	1.36b	91.08c	44.25c	29.83bc	74.08c
NanoSiO2	50	1.09d	99.00a	57.62a	37.58a	95.20a
	100	1.21c	96.25ab	47.48bc	31.39b	78.87c
Control	0	1.51a	95.50ab	34.66d	26.70c	61.37d

Means in each column followed by the same letters are not significantly (P < 0 .05) different according to Duncan's multiple range test.

Azimi et al.⁸ said that application of nanoSiO₂ significantly increased tall wheatgrass germination about 86.3 and 85.7 percent in 40 and 60 mg L⁻¹, respectively. Also, they indicated that applying nanoSiO₂ improved dry weight of shoot, root and seedling of tall wheatgrass. Adhikari et al.¹ revealed that nanoSiO2 had no toxic effect on rice growth, and applying nanoSiO2 enhanced the root length, root volume and dry matter of shoot and root of rice. Similar resulted about nanoparticles were reported by Haghighi et al.¹⁹ Zheng et al.³⁶

The results showed that even though lengths and dry weights of shoot, root and seedling decreased with the increasing nanosized SiO₂ concentrations, but there was no significant difference with increasing bulk SiO₂ concentrations except in case of shoot and seedling lengths (Tables 4 and 5). It seems that bulk and nanosized SiO₂ in appropriate concentrations could improve the germination characteristics of fenugreek in comparison to control treatment. Feizi et al.¹⁵ realized that the growth of wheat seedling was greatly improved at 2–10 ppm nano TiO₂ concentrations, but there was no improvement at higher concentrations.

Table 5.

The effect of bulk and nanosized SiO₂ concentrations on germination characteristics of fenugreek.

Materials type	Concentration (ppm)	Shoot dry matter (mg)	Root dry matter(mg)	Seedling dry matter (mg)	Vigor index I (mg)	Vigor index II (mg)
Bulk SiO2	50	6.13bc	1.08c	7.21c	812.84b	688.20c
	100	5.90cd	1.01cd	6.92cd	677.21c	633.27d
NanoSiO2	50	7.15a	1.52a	8.75a	944.24a	867.25a
	100	6.46b	1.25b	7.72b	762.73b	746.28b
Control	0	5.65d	0.93d	6.58d	588.66d	631.34d

Means in each column followed by the same letters are not significantly (P < 0 .05) different according to Duncan's multiple range test.

Treating fenugreek seeds with 50 ppm nanosized SiO₂ lead to the highest increase in shoot length by 66 percent and seedling length by 55 percent compared to control treatment. Higher root length was noted in 50 ppm nanosized (37.58 mm) treatment that, there was no significant difference with 50 ppm bulk SiO₂. Lu et al.²⁵ revealed that a combination of nanosized TiO₂ and SiO₂ could increase the nitrate reductase enzyme in soybean (Glycine max) and its abilities of utilizing water and fertilizer which in fact end up to accelerate its germination and growth.

Use of 50 ppm nanosized SiO₂ significantly improved dry weights of shoot, root and seedling around 26, 66 and 32 percent, respectively in comparing to control treatment (Table 5). But, enhancing in root dry weight had more significant role than shoot dry weight in the improvement of seedling dry weight. It seems that nanoSiO₂ facilitates water absorption and its transportation into fenugreek seedling. Beneficial roles of nanoSiO₂ can be related to its hydrophilic.³² Torabi et al.³⁵ reported that different concentrations of silicon had considerable effect on the germination rate, germination index, seedling growth and the total dry and fresh weight of borage seedling (Borago officinalis L.). Also they presented that silicon had a priming effect and could prepare a suitable metabolic reaction in seeds and promotes seed germination performance and seedling establishment.

The highest vigor indexes (I) and (II) were in 50 ppm nanosized SiO₂ about 60 and 37 percent, respectively comparison to control treatment. Zheng et al.³⁸ reported that nanoTiO₂ caused to water uptake by spinach seeds and as result expedited seed germination. Feizi et al.¹⁵ revealed that the highest vigor index was in 2 and 10 ppm nanoTiO₂ treatments.

Siddiqui and Al-Whaibi³⁴ indicated that nanoSiO₂ improved seed germination percent, mean germination time, seed germination index, seed vigor index, seedling fresh weight and dry weight of tomato (Lycopersicum esculentum Mill. cv Super Strain B).

In the combined treatments of bulk, nanosized SiO₂ and salinity levels, increasing salinity caused a significant increasing in mean germination time, while bulk and nanosized SiO₂ caused decreasing it (Table 6). 50 ppm nanosized SiO₂ under zero mM salt showed positive effects and decreased mean germination time about 65 percent comparison to control treatment (Table 4). Applying 50 ppm nanosized SiO₂ under all of salt concentrations and 100 ppm nanosized SiO₂ under zero mM salt showed the highest germination percentage. Also, there was no significant difference with 50 ppm bulk SiO₂ under zero mM salt (Table 6).

Table 6.

The interaction effect of salinity, bulk and nanosized SiO₂ concentrations on germination of fenugreek.

NaCl (mM)	Concentration (ppm)	MGT (day)	Germination (%)	Shoot length(mm)	Root length(mm)	Seedling length(mm)
	Bulk SiO2
0	50	1.00i	99.00a	64.01bc	42.00ab	106.01ab
0	100	1.05i	95.00bcd	52.00fgh	38.84b	90.84c
50	50	1.16h	93.00de	59.00cde	33.50cd	92.50c
50	100	1.24fgh	90.00e	50.66gh	30.00def	80.66d
100	50	1.15h	93.00de	47.33hi	30.00def	77.33d
100	100	1.26fg	89.00e	44.00ij	27.00fgh	71.00e
150	50	1.65cd	94.00d	36.00l	29.33ef	65.33fg
150	100	1.90b	89.00e	30.33m	23.50hij	53.83j
	Nano SiO2
0	50	0.70k	100.00a	69.66a	44.33a	111.33a
0	100	0.90j	100.00a	60.43cd	40.25b	100.68b
50	50	0.86j	100.00a	67.00ab	39.66b	109.33a
50	100	0.95ij	96.00bcd	54.83efg	34.00cd	88.83c
100	50	1.20fgh	98.00abc	56.50def	33.33cde	89.83c
100	100	1.27f	95.66bcd	41.66jk	29.33ef	71.00e
150	50	1.62d	98.00abc	37.33kl	33.00cde	70.33ef
150	100	1.74c	93.33de	33.00lm	22.00ij	55.00ij
	Control
0	0	1.16gh	98.66ab	45.00ij	34.50c	79.50d
50	0	1.41e	96.00bcd	36.00l	27.66fg	63.66gh
100	0	1.46e	94.33cd	34.66lm	25.00ghi	59.66hi
150	0	2.01a	93.00de	23.00n	19.66j	42.66k

Means in each column followed by the same letters are not significantly (P < 0.05) different according to Duncan's multiple range test.

Seedling growth parameters attributes significantly improved when bulk and nanosized SiO₂ concentrations applied singly or with different levels of salt stress. However, they significantly declined with salt application (Tables 6 and 7). Under zero and 50 mM salt also, 50 ppm nanosized SiO₂(54 and 86 percent, respectively) treatments, the results indicated the least reduction on Shoot length comparing to control treatment (Tables 6).

Table 7.

The interaction effect of salinity, bulk and nanosized SiO₂ concentrations on germination of fenugreek.

NaCl (mM)	Concentration (ppm)	Shoot dry matter (mg)	Root dry matter(mg)	Seedling dry matter (mg)	Vigor index I (mg)	Vigorindex II (mg)
	Bulk SiO2
0	50	7.44b	1.35d	8.80c	1060.13ab	880.00c
0	100	7.47b	1.23de	8.70c	863.26c	827.02d
50	50	6.90c	1.20ef	8.10d	859.55c	753.16ef
50	100	6.10e	1.07fg	7.17ef	726.00e	645.90h
100	50	5.50fgh	0.97gh	6.46g	718.50e	601.41i
100	100	5.16hi	0.93hi	6.10hi	633.96fg	548.05j
150	50	4.70jk	0.80i	5.50j	613.20gh	518.26j
150	100	4.88ij	0.82i	5.70j	485.61j	512.13j
	Nano SiO2
0	50	8.52a	2.00a	10.52a	1113.33a	1052.33a
0	100	7.80b	1.70b	9.50b	1006.83b	950.66b
50	50	7.66b	1.56c	9.23b	1093.33a	923.33bc
50	100	6.91c	1.25de	8.16d	852.80c	784.00de
100	50	6.60cd	1.31de	8.20d	880.76c	803.92d
100	100	5.74efg	1.08fg	6.83f	678.30ef	653.92h
150	50	5.82ef	1.21ef	7.03f	689.53e	689.44gh
150	100	5.40gh	0.98gh	6.39gh	513.00ij	596.56i
	Control
0	0	6.80cd	1.24de	8.04d	784.40d	793.56de
50	0	6.51d	0.96gh	7.47e	611.33gh	717.94fg
100	0	4.91ij	0.91hi	5.82ij	561.33hi	549.14j
150	0	4.38k	0.60j	5.00k	397.60k	464.71k

Means in each column followed by same letters are not significantly (P<0 .05) different according to Duncan's multiple range test.

Treatment of 50 ppm nanosized SiO₂ under zero mM salt increased root length about 28 percent comparison to the control treatment. There was no significant difference with 50 ppm bulk sized SiO₂ treatment (Table 6). Silicon appears 2 isolated functions in root cell walls, reinforcement of the endodermal cell walls in the mature basal region and keeping the young spreading cell walls extendible in the roots apical region.¹⁸ Applying of silicon seems to be quite useful to plants grown under water deficit conditions by encouraging the expansion of a big root system and keeping roots against soil drying.

Seedling length of fenugreek enhanced as a result of 50 ppm nanosized SiO₂ application under zero mM salt about 36 percent compared to control. There was no significant difference with 50 ppm nanosized SiO₂ under 50 mM salt and 50 ppm bulk SiO₂ under zero mM salt treatment. Salinity interaction with bulk and nanosized SiO₂ showed increasing dry weight (Table 7).

An increase in growth of salt stressed fenugreek seeds with the application of bulk and nanosized SiO₂ in the growth medium may be due to the fact that bulk and nanosized SiO₂ increasd photosynthesis rate, which was related with content of chlorophyll, activity of ribulose biphosphate carboxilase, and leaf ultra-structure.

Similar results were also presented in barley, cucumber and soybean.^2,17,23 Salt stress adversely effect fenugreek growth attributes and results of current research confirm that all growth parameters decreased with NaCl salt application. Clément et al.¹² demonstrated that 100 ppm anatase nanoparticles increased seed germination and root growth of flax. These beneficial effects might be due to antimicrobial properties of anatase crystalline structure of TiO₂ that enhance plant tolerance to stress.¹²

Shoot, root and seedling dry weights of fenugreek enhanced with elevated bulk and nanosized SiO₂, while decreased with NaCl application as compared to control. Under salt stress condition, addition of 50 and 100 ppm nanosized SiO₂ to fenugreek seeds increased shoot, root and seedling dry weights as compared to bulk SiO₂ concentrations and control treatments, though 50 ppm nanosized SiO₂ was more effective than 100 ppm nanosized SiO₂ application. Applying of 50 ppm nanosized SiO₂ under zero mM salt increased shoot, root and seedling dry weights around 25, 61 and 30 percent, respectively over the control (Table 7).

Use of 50 ppm nanosized SiO₂ under zero mM salt showed beneficial effects and increased vigor index I about 41 percent comparison to control treatment. There was no significant difference with 50 ppm nanosized SiO₂ under 50 mM salt and 50 ppm bulk SiO₂ under zero mM salt (Table 7). Among the treatments, applying of 50 ppm of nanosized SiO₂ showed the highest values for vigor index II. The results indicated that nanosized SiO₂ in an appropriate concentration could promote the percentage germination and seedling growth of fenugreek in comparison to bulk SiO₂ concentrations and control.

Navarro et al.³⁰ presented that engineered nanoparticles having high specific surface area could sequester nutrients on their surfaces and thus serve as a nutrient stock to the organisms. These positive effects could be probably due to the antimicrobial properties of engineered nanoparticles, which can promote strength and tolerance of plants to stress. Similar resulted were reported by other researchers that confirm the positive effects of bulk and nanosized SiO₂ at salt stress. They observed that nanoSiO₂¹⁹ and silicon application^{40,22,14,21,26,37,29,3} could ameliorate salinity damages on plant species.

Haghighi et al.¹⁹ indicated that nanoSiO₂ improved germination characteristics such as germination rate, root length and dry weight in tomato under salinity stress. Lin et al. (2004) revealed that 500 ppm nanoSiO₂ significantly increased mean height and root traits of changbai larch. Higher activities of SOD, GPX, APX, DHAR and GR in salt-stressed cucumber leaves induced by silicon addition could ameliorate salinity stress damages from plant tissues, thus mitigated salt toxicity and increasing the growth of cucumber plants.³⁹ Nasseri et al.²⁹ showed that supplementary silicon at 1.5 mM ameliorated the negative effects of salinity on fenugreek dry matter and chlorophyll content. Also, they reported that the silicon increased the tolerance to salt stress. Kafi et al.²¹ observed that soil application of 1.44 g.kg⁻¹ silicon caused an increase in the activities of APX, peroxidase (PRO), catalase (CAT), glutathione reductase (GR), superoxide dismutase (SOD) total antioxidant.

Wang et al.³⁷ tested that applying silicon at plants under salinity stress could increase antioxidative enzymes activity like SOD, POD and CT which played great role to counter balance salinity damages. Zuccarini⁴⁰ presented that silicon application leaded to balance growth reduction of Phaseolus vulgaris L. caused by salinity like decrease stomata conductance, drop of leaf RWC, decrease K⁺ tissues content. Liang et al.²⁴ presented that antioxidant system stimulation and specific ion effect alleviation by decreasing sodium uptake were also environmental stresses tolerance mechanisms in plants exposed to application of silicon.

Conclusions

Interaction effects of salinity levels, dosage and size of SiO₂ were studied by measuring the germination indices and vigor index of fenugreek seeds. The results indicated that the inclusion of bulk and nanosized SiO₂ in fenugreek nutrition under stressed environmental conditions are beneficial, as our research showed that bulk and nanosized SiO₂ significantly improved growth attributes and effectively mitigated the adverse effects of NaCl induced salt stress. We also found that the nanosized SiO₂ treatments in proper concentration accelerates the germination of the fenugreek seeds and increases their vigor. NanoSiO₂ improves the mean germination time and growth of fenugreek seedling in comparison to bulk SiO₂ and control. 50 ppm nanosized SiO₂ was more effective in alleviating salinity than 100 ppm nanosized SiO₂ treatment. However, further researches are needed for a better understanding of the physiological or biochemical roles of bulk and nanosized SiO₂ in higher plants at molecular level.

Disclosure of potential conflicts of interest

No potential conflicts of interest were disclosed.

Acknowledgments

The authors acknowledge Mr. Dr. Rezvani moghadam and Mr. Sadeghi for offering physiology Lab. We thank Mrs. Dadi for help during test of seed germination.