Essay: The effect of arbuscular mycorrhizal fungi and potassium silicate in alleviating the adverse impact of salt stress in Thevetia peruviana

Abstract
The current investigation was carried out to evaluate the effect of arbuscular mycorrhizal (AM) fungi and potassium silicate (K-Si) in alleviating adverse impact of salt stress in Thevetia peruviana. The plants were irrigated with water salinity (0, 4.7, 9.4 and 14.1 dSm-1 sodium chloride (NaCl) with and without application of AM-fungi or K-Si. Potassium silicate had a stimulating effect on plant height, branches and leaves number, whereas, AM fungi gave the thickest plants and heaviest fresh and dry weight of shoots and roots.
Salt stress caused significant decrease in chlorophyll and carotenoid contents, however, the application of AM fungi and K-Si restored the pigments content in salt-affected plants and that might interpret the overproduction of total carbohydrates which are supplied mainly through the process of photosynthesis. Proline, phenol and phenol/Indol ratio were increased with increasing concentration of NaCl, but lower accumulation has been reported in plants treated with any of the anti-salinity. Maximum soil enzymatic activities, in rhizospheric soil were recorded with unstressed plants and receiving inoculation of AM fungi followed by that recorded for plants treated with K-Si and minimum activity were recorded in soil under no inoculation and stressed plants. NaCl stress also showed decrease in different enzymes activities (nitrogenase, dehydrogenase and phosphatase), and number of AM spores, further increase was observed in plants treated with AM fungi.
The applied salinity levels caused gradual increases in Na+ and Cl percentages accompanied by gradual decreases in N, P, Ca and K percentages as well as ratios of K+ / Na+ and Ca+2/ Na+ relative to the control plants (unstressed). Concerning K-Si and AMF effects on mineral content, it was found increases in the percentages of P, K and Ca as well as ratios of K+ /Na+, Ca+2/Na+ ratio and N relative to unstressed plants. K+ /Na+ ratio in plants under saline conditions is considered as one of the important selection criteria for salt tolerance.
Results indicated that K-Si and AM fungi treatments improved the endogenous nutrients, growth parameters attributes under different levels salinity stress.
Keyword: Thevetia peruviana- salinity – potassium silicate – K-Si – arbuscular mycorrhizal fungi- salt stress ‘ AMF- K/Na
INTRODUCTION
Thevetia peruviana is a plant of tropical, a fast-growing small tree and because of its beautiful flowers and slender leaves very decorative effect. Its flowers have different colors, yellow, white and orange. The tree blooms, the leaves are linear-lanceolate, glossy and green almost all year round. They are coated with a waxy layer to reduce water loss. Its considered as an ornamental tree. Thevetia peruviana plants can succeed in rather poor and dry soils. It can tolerate shorter dry periods and moderately saline soils. Its best grows and flowers in full sun or light shade. T. peruviana contains a number of phytoconstituents which reveals its uses for different therapeutic purposes. The individual parts of plant can be used for the treatment of different disorders in human being such as, liver toxicity, diabetes, fungal infection, inflammation, microbial infection, pyrexia and to relieve pain. Furthermore, so much work is required with the thevetia to investigate the mechanism of actions with other therapeutic activities (Singh Kishan et al. 2012 and Ramos-Silva et al. 2017).
Among the abiotic stresses, salinity is one of the main factor that contributes to desertification of arid lands. Soil salinization has become a great challenge for rehabilitation of range lands and plant productivity (Alqarawi et al. 2014). Salinity causes nutritional disorders in plants which lead to deficiencies of several nutrients and drastically increasing Na+ levels in the plant cells (Iqbal and Ashraf, 2013).Thus, salinity stress affects the plant ability to uptake water in the root zone through decreasing the water potential of the soil (Sabir et al., 2009). This deficiency in available water under saline condition raises the potential of cells to be dehydrated which is a result of the osmotic stress caused by salinity. The higher ratios of toxic ions like Na+ and Cl damage the balance between ions through reducing the plant ability to absorb other ions like K+, Ca2+, and Mn2+ (Hasegawa et al., 2000). In this regard, the application of AM fungi as a biological method could improve plant growth and tolerance through helping the plants to mitigate the negative the adverse effects of salinity ( Abdel-Fattah and Asrar, 2012; Asrar et al., 2014).
Plants can overcome salinity by interacting with beneficial soil microorganisms such as arbuscular mycorrhiza fungi (AMF). Mycorrhiza symbiosis is a close association with the roots of most plants, from which both partners benefit: carbon compounds are supplied by the plant to the fungus, which provides the plant with mineral nutrients, mainly phosphate. AM symbiosis is able to increase plant growth under different environmental stresses (Garg and Chandel, 2015). The result is improved growth of the plant, and completion by the fungus of its life cycle. AM-fungi is known to exist in saline soil, and participates in the plant growth and development, and also improves the plant tolerance against biotic and abiotic stress (Abdel-Fattah et al., 2010) by regulating the physiological and biochemical process of plants (Fernanda et al., 2012).
AM fungi acts as growth regulator and mitigate the harmful effects of plants exposed to salt stress. Its play a key role in alleviating the toxicity induced by salt stress thus normalizing the uptake mechanism in plants by supplying the essential nutrients. The plant recovers the water balance machinery, enhancing their tolerance capacity, and thereby enduring the salt stress (Bhosale and Shinde 2011). Heikham et al. (2009) suggested many physiological parameters which could be responsible for alleviation of the harmful effects of salinity on plants upon inoculation with AM :
1) maintenance of a high K/Na ratio, 2) improved acquisition of nutrients such as N, P, Mg and Ca; 3) extended accumulation of proline, GB, polyamines, and carbohy-drates, 4) enhanced activation of antioxidant enzymes, 5) increased chlorophyll content and higher rates of photosynthesis, 6) improved integrity and stability of cell membranes, 7) higher hydraulic permeability and improved water status, 8) increased number of nodules and nitrogen fixation by legumes, 9) molecular changes, such as enhanced expression of the plasma membrane intrinsic protein (PIP) gene, expression of two Na+/H+ antiporters, and expression of genes encoding.
Silicon (Si) is a beneficial element as it improves growth, confers rigidity, strength and enhances plant tolerance to various abiotic stresses (Meena et al. 2014;Abbas et al. 2015). It is always combined with other elements, usually forming silicates and oxides (Gunes et al. 2007). Plant roots generally take up Si in the form of silicic acid which then translocate to the shoot, where it is polymerized to form silica gel (SiO2nH2O) (Zhu and Gong 2014). Exogenous application of Si has been reported to induce favorable effects on plant growth under abiotic stresses (Balakhnina et al. 2015). Many studies have indicated the role of Si in alleviating salt-stress have been attributed to reduced uptake and translocation of Na+ to shoots (Al-Aghabary et al. 2004), maintenance of plant’water relations (Gong et al. 2006), which in turn, contributes to salt dilution (Romero-Aranda et al. 2006). Thus the objective of this study was to investigate of K-silicate or AM-fungi mediated salinity tolerance mechanism for developing Thevetia peruviana resistance to salt stress.
MATERIALS AND METHODS
Experimental design:
To achieve the aforementioned target, a pot experiment was conducted at the Nursery of the Department of Ornamental and landscape Gardening Research during two successive summer seasons (2015 and 2016). Seedlings of Thevetia peruviana (60 cm height of plant) were obtained from a commercial nursery, where healthy seedlings of uniform size were selected and transplanted into pots (30 cm diameter) which contain 7 kg of soil (60.7 % clay, 25.8% silt and 13.5% sand). After 3 weeks of transplanting seedling, salt was applied as a water solution of sodium chloride concentrations (0, 4.7, 9.4 and 14.1 dSm-1 NaCl respectively, where 0 dSm-1 means no added NaCl) with and without AM or K-Si inoculations. All pots were irrigated to reach field capacity with saline solutions to maintain the level of salinity after transplanting. Plants were received NPK (Krystalon 19-19-19) at the rate of 2g pot-1 with other treatments after two weeks from transplanting then one monthly interval during the growth seasons. Plants were supplemented twice a week with 500 mL of a salinity solution per pot. Each experiment included 4 salinity levels and two antisalinity application {arbuscular mycorrhiza (AM) fungi, and potassium silicat (K-Si)} plus control without treatment application (12 treatments) replicated 3 times in a completely randomized design.
Soil characteristics:
Some physical and chemical properties of the experimental soil and water used were determined according to the standard methods undertaken by Black et al., (1965); Chapman and Pratt (1961), Page et al., (1982), and the obtained data are presented in Table (1).
Table (1): Some physical and chemical characteristics of the studied soil
Soil characteristics Value Soil characteristics Value
Particle size distribution%: Soluble cations (soil paste mmolecL-1):
Sand 13.5 Ca2+ 2.73
Silt 25.8 Mg2+ 1.15
Clay 60.7 Na+ 1.85
Textural class Clay K+ 0.60
Soil chemical properties: Soluble anions (soil paste mmolecL-1):
pH (soil paste extract) 8.15 CO32- 0.00
CaCO3 % 3.15 HCO3- 1.50
Organic matter % 1.12 Cl- 2.05
ECe (dS/m, soil paste extract) 0.69 SO42- 3.00
Soil physical properties:
Bulk density g cm-3 1.37 Soil moisture at wilting point % 8.69
Soil moisture at field capacity % 21.00 Avail. Water % 12.31
Available Nutrients mg kg-1
N P K Cu Fe Mn Zn
27.40 4.12 374.50 0.65 3.84 0.95 0.78
Ant-salinity applications
Arbuscular Mycorrhizal Fungi (AMF) mycorrhizal pot treatments received the AMF by placing 200 g of mycorrhizal inoculum as soil application at the transplanting time. The AM inoculum consisted of soil AM colonized roots, rhizosphere soil having extramatrical mycelium and spores (approximately, 250-300 spores 100g-1 of soil) were used for each mycorrhizal pot treatments. The inoculum was placed five cm below each plant.
Potassium silicate(K-Si)The plants were treated with potassium silicate (11:25% K2O:SiO2) at rate of 5 ml pot-1as soil application at the transplanting time.
Growth measurement and biochemical analysis
In both growing seasons, samples were selected randomly and the following growth characters were recorded:
Plant height (cm); branches number plant-1; leaves number plant-1; shoots fresh and dry weight (g); Stem diameter (mm) and leaf area (cm2)
Roots length (cm) and roots fresh dry weight (g).
Quantification of the Number AM Spores was done using the Adholeya and Gaur ‘Grid Line Intersect Method’ (1994).
Determination of Photosynthetic Pigments were determined in representative fresh leaves samples. Chlorophyll and carotenoids were extracted and determined according to Lichtenhaler and Wellburn (1983) method.
Bio-chemical Composition
Proline: was determined according to the method of Petters et al. (1997).
Phenols and indoles in leaves were determined according to A.O.A.C. (2000) and Larsen et al. (2006), respectively.
Total carbohydrates: was determined according to Herbert et al. (2005)
The enzymes activity: nitrogenase (”mole C2H4.g dry nodule-1day-1), dehydrogenase (”g TPF.g dry soil-1.day-1) and phosphatases (”g.g dry soil-1) were determined according to the methods described by Somasegaran and Hoben, (1994), Skujins (1976) and Tabatabai and Bremner (1969), respectively.
Crude protein percent calculate as, nitrogen was multiplied by 6.25 (A.O.A.C., 2000).
Mineral Content
Nitrogen was determined in plants with sulfuric acid using the semi-micro Kjeldahl method Walinga et al.(1995). Phosphorous was determined by colorimetric method (A.O.A.C., 2000). Potassium and calcium in shoots were determined using flame photometer apparatus according to Walinga et al (1995).
The experiment was laid as completely randomized in a factorial design, the obtained data were statistically analyzed using LSD test at 5% (Mead et al, 1993).
RESULTS AND DISCUSSION
Vegetative Growth
Vegetative growth of Thevetia peruviana was more superior under (0 dSm-1 NaCl) as compared with plants grown under salt stress conditions (Tables 2,3 and 4). On the contrary, with the increase of salinity stress levels the vegetative growth characters of Thevetia peruviana expressed as plant height, stem diameter, number of branches (Table 2), number and area of leaves and plant fresh and dry weights (Tables 3 and 4) were significantly decreased mainly at the highest salinity level (14.1 dSm-1) in both studied seasons. Anti-salinity treatments (Mycorrhiza and potassium silicate) improved all mentioned plant vegetative growth characters affected by salt stress compared with untreated plants (control). It was shown that AM-fungi
Table (2): Effect of applied treatments on plant height, stem diameter and branches number of T.peruviana irrigated with different levels of water salinity.
Salinity levels
(dSm-1) A
First season Second season
Treatments (B)
control K-Si AMF Mean control K-Si AMF Mean
Plant height (cm)
0.0 98.75 110.30 107.25 105.40 109.90 117.80 116.10 114.60
4.7 82.00 93.17 82.92 86.03 85.58 104.10 100.60 96.75
9.4 78.33 83.00 81.58 80.97 80.25 84.75 83.33 82.78
14.1 73.75 80.92 80.08 78.25 79.08 82.08 81.75 80.97
Mean 83.21 91.83 87.96 88.71 97.18 95.43
LSD at 5% A: 0.42 B: 0.36 AB: 0.72 A: 0.50 B: 0.43 AB: 0.86
Stem diameter (mm)
0.0 14.94 17.09 18.57 16.87 15.64 16.29 19.74 17.22
4.7 13.58 14.57 15.10 14.42 14.77 16.71 17.37 16.28
9.4 12.29 13.94 14.27 13.50 12.70 15.58 16.96 15.08
14.1 11.08 12.34 13.04 12.15 11.55 15.74 15.11 14.13
Mean 12.97 14.48 15.24 13.66 16.08 17.30
LSD at 5% A: 0.031 B: 0.027 AB: 0.054 A: 0.99 B: 0.86 AB: 1.72
Branches number plant-1
0.0 10.17 11.67 11.00 10.95 11.33 12.33 11.93 11.86
4.7 9.50 11.50 10.00 10.33 10.67 12.00 11.33 11.33
9.4 8.73 10.83 9.33 9.63 9.43 11.67 10.64 10.58
14.1 8.50 9.17 8.93 8.94 8.94 10.50 9.83 9.76
Mean 9.23 10.79 9.87 10.09 11.63 10.93
LSD at 5% A: 0.21 B: 0.18 AB: 0.36 A: 0.15 B: 0.13 AB: 0.27
K-Si: Potassium silicate AMF: Arbuscular mycrrohizae fungi
application significantly mitigated the effects of low salt stress (4.7 dSm-1) and moderately counteracted the destructive effects of high salt stress level (9.4 and 14.1 dSm-1) of most vegetative growth parameters followed by K-Si treatment. The same trend was found in the two studied seasons. Such results are in harmony with other previous investigations who demonstrated that, decreases in vegetative growth as a result of increasing concentration of salt irrigated water, El-Zait (2011) on Conocarpus erectus plant, Kafi and Rahimi (2011) on Portulaca olercea plant and El-Sayed (2013) on Moringa oleifera plant. As demonstrated in result tables application of K-Si had a stimulating effect on the plant growth, improved plant height, leaf area, branches and leaves number, whereas (AM) gave the thickest plants and heaviest fresh and dry weight of shoots and roots, Manivannan et al (2015) on Zinnia elegans. Watfa (2009) confirmed that AM fungi gave a positive overall impact on plant biomass under salt stress conditions, with both shoot and root dry weights being significantly greater in mycorrhizal than in nonmycorrhizal on Ceratonia siliqua L.and Garg and Bhandari (2016) on Cicer arietinum plant, reported that the silicon and arbuscular mycorrhiza increase the growth parameters under salinity stress.
Table (3): Effect of applied treatments on leaf area, leaves number and roots fresh and dry weight of T.peruviana irrigated with different levels of water salinity.
Salinity levels
(dSm-1) A First season Second season
Treatments (B)
control K-Si AMF Mean control K-Si AMF Mean
Leaf area (cm2)
0.0 4.31 6.26 5.78 5.45 7.26 8.92 8.29 8.16
4.7 2.61 3.10 3.07 2.92 3.43 4.13 3.67 3.74
9.4 1.16 2.57 2.27 2.00 1.64 3.39 3.37 2.80
14.1 1.01 2.05 1.56 1.55 1.42 2.52 2.45 2.13
Mean 2.27 3.50 3.17 3.44 4.74 4.45
LSD at 5% A: 0.03 B: 0.03 AB: 0.05 A: 0.03 B: 0.03 AB: 0.05
Leaves number plant-1
0.0 264.70 433.70 420.33 372.89 337.00 441.00 393.00 390.33
4.7 131.00 196.00 174.33 167.11 145.00 208.00 203.00 185.33
9.4 95.00 139.00 119.70 117.89 121.00 140.67 131.67 131.11
14.1 80.93 115.00 112.50 102.81 91.33 125.00 117.00 111.11
Mean 142.90 220.92 206.71 173.58 228.67 211.17
LSD at 5% A: 2.54 B:2.20 AB: 4.40 A: 2.35 B: 2.04 AB: 4.08
Shoot f.wt.(gm)
0.0 128.90 163.65 178.45 157.00 130.64 181.82 190.06 167.51
4.7 87.97 94.96 99.51 97.15 91.55 107.77 126.17 108.50
9.4 69.64 90.96 95.04 85.21 75.08 104.70 109.27 96.35
14.1 52.73 76.52 88.51 72.59 70.22 94.23 96.26 86.90
Mean 84.81 106.52 115.38 91.87 122.13 130.44
LSD at 5% A: 1.98 B: 1.72 AB: 3.43 A: 2.03 B: 1.76 AB: 3.52
Shoot d.wt.(gm)
0.0 59.21 75.45 77.37 70.68 60.62 79.79 83.13 74.51
4.7 39.20 40.24 43.26 40.90 39.69 49.20 55.32 48.07
9.4 27.78 39.41 39.96 35.72 33.57 46.52 48.64 42.91
14.1 19.43 28.96 36.58 28.32 31.99 41.21 42.00 38.40
Mean 36.41 46.02 49.29 41.47 54.18 57.27
LSD at 5% A: 1.23 B: 1.06 AB: 2.12 A: 1.76 B: 1.53 AB: 3.05
Table (4): Effect of applied treatments on roots length, fresh and dry weight of T.peruviana irrigated with different levels of water salinity.
Salinity levels
(dSm-1) A
First season Second season
Treatments (B)
control K-Si AMF Mean control K-Si AMF Mean
Root length (cm)
0.0 57.60 69.47 74.83 67.30 68.53 71.53 76.90 72.32
4.7 50.83 59.67 68.00 59.50 53.50 62.70 73.67 63.29
9.4 37.00 49.67 53.50 46.72 42.77 56.65 57.77 52.40
14.1 33.68 39.00 39.17 37.28 37.67 43.20 50.10 43.66
Mean 44.78 54.45 58.88 50.62 58.52 64.61
LSD at 5% A: 1.57 B: 1.36 AB: 2.72 A: 1.63 B: 1.42 AB: 2.83
Root f.wt. (gm)
0.0 59.69 63.74 89.58 71.00 61.41 88.45 96.90 82.25
4.7 41.06 49.13 50.70 46.96 46.08 59.41 60.71 56.72
9.4 33.64 42.34 44.13 40.04 39.10 52.60 57.19 49.63
14.1 29.13 39.39 39.94 36.15 38.58 49.49 50.05 44.90
Mean 40.88 48.65 56.09 46.29 62.49 66.21
LSD at 5% A: 0.29 B: 0.25 AB: 0.51 A: 0.35 B: 0.30 AB: 0.61
Root d.wt. (gm)
0.0 35.92 37.90 53.32 42.38 36.84 40.39 56.73 44.65
4.7 23.30 28.15 29.94 27.13 26.79 32.40 34.70 31.30
9.4 18.50 24.51 27.01 23.34 23.21 30.72 31.65 28.53
14.1 15.29 21.49 21.77 19.52 21.58 22.96 24.78 23.11
Mean 23.25 28.01 33.01 27.10 31.62 36.97
LSD at 5% A: 0.31 B: 0.27 AB: 0.53 A: 0.29 B: 0.25 AB: 0.51
K-Si: Potassium silicate AMF: Arbuscular mycrrohizae fungi
Biological activity
Enzymatic activity and Number of AM Spores
The effect of plants can be related to the roots secretion which changes in soil organic matter content and microbial populations (rhizosphere effect). Raddy et al. (1987) proved that enzymes activity were higher in rhizosphere soils than in before planting and non-rhizosphere soils. Soil enzymes are an indicator of soil biological activity because enzymes are the products of vital activity, and their activities may reflect the states of soil biological metabolism and material transformation, Siddikee et al. (2011), Guan et al. (2014), and Lemanowicz (2015). As evident from Fig.(1), the plants inoculated with AM fungi and K-silicat significantly influenced the nitrogenase, dehydrogenase and phosphatase enzymes activity, in rhyzospheric soil of Thevetia peruviana. Maximum soil enzymatic activities, in soil were recorded with unstressed plants under treatment receiving inoculation of AM fungi followed by that recorded for plants treated with K-Si and minimum activity were recorded in soil under no inoculation and stressed plants. The increase in salinity levels had a negative effect on soil’s microbiological activity. The enzymes activity in rhyzospheric soil were inhibited even at low salinity levels, but the addition of AM fungi and potassium silicate decreased the toxic effects.
Data in Fig.(2) indicated that, the plants unstressed (0 dS m’1) treated with or without K- Si or AM-fungi had a greater number of AM spores compared to higher and lower salinity levels. The uninoculated treatment gave the least spores number as the presence of AM fungi in these treatment depended mainly on native mycorrhiza compared to treated plants. The salt concentrations 4.7, 9.4 and 14.1 dSm”’ caused significant decrease in AM spores quantitates to 10.6%, 16.9 % and 40.0% respectively, compared to control (unstressed), in absence of K-Si and AMF, whereas, increase AM spores in presence of K-Si 51.2%, 44.2%, 38.5% and 9.8% and 148.8%, 144.6%,103.2% and 66.8% at 0, 4.7, 9.4 and 14.1 dSm”’, in presence of AMF, respectively, compared to control (stressed). Spores number of AMF is reduced in the presence of NaCl (Sheng et al., 2008) probably due to the direct effect of NaCl on the fungi (Juniper and Abbott, 2006) indicating that salinity suppresses the formation of arbuscular mycorrhiza (Tian et al., 2004 and Sheng et al., 2008). A high soil salinity may not reduce mycorrhization, as increased mycorrhization under high saline conditions is reported by Aliasgharzadeh et al. (2001) and Yamato et al. (2008). The upper limit of the salinity tolerance of the AMF used in this experiment was 14.1 dS m’1, the level at which spore numbers were reduced. Decreased mycorrhization
Fig. (1) Effect of applied treatments on enzymes activity in rhizospheric soil of T.peruviana irrigated with different levels of water salinity
could be due to the high salt concentrations inhibiting the germination of fungal spores. Even though high salinity caused a decrease in mycorrh-ization, the symbiosis between roots and AM fungi strengthens once the association is established, which indicates the importance of this symbiosis for plant production under saline conditions (Rabie and Almadini 2005).
Fig. (2) Effect of applied treatments on spores number of AM-fungi in rhizospheric soil of T.peruviana irrigated with different levels of water salinity.
Chemical constituents
Photosynthetic Pigments
Salinity caused considerable decline in chlorophyll and carotenoid with the effect being more obvious under higher concentrations (14.1dSm-1). At higher salt concentration, percent reduction in chlorophyll a, chlorophyll b and carotenoid contents was 56.02%, 57.96% and 42.83% respectively while as K-Si and AMF treatments salinity stressed plants showed only 51.22%, 50.66%, 40.50% and 45.42%, 50.22%, 40.40% decline respective-ely, (Table 5). Relative to control, K-Si and AMF increased chlorophyll a, b and carotenoid contents by 10.8%, 9.3%, 1.1% and 20.9%, 20.8%, 5.0%, respectively, the same trend was observed in the second season. Reduction in chlorophyll and carotenoid contents observed in our experiment is in corroboration with the findings of Alqarawi et al. (2014 b) and El-Zait (2011) for Ephedra alata and Conocarpus eretus, respectively. Increased use of saline water irrigation caused considerable decline in photosynthetic pigment content and hence reduced growth. The fungi are able to alleviate the antagonistic effects of Na on Mg uptake under salt stress (Giri et al., 2003) AMF inoculated plants enhanced chlorophyll synthesis and subsequent amelioration of salinity stress induced deleterious effect may be due to the increased uptake of magnesium which forms an important part of chlorophyll pigment molecule (Aroca et al., 2013).
Table (5): Effect of applied treatments on chlorophyll a, b, carotenoids and Proline of T.peruviana irrigated with different levels of water salinity.
Salinity levels
(dSm-1) A First season Second season
Treatments (B)
control K-Si AMF Mean control K-Si AMF Mean
Chlorophyll a (mg g-1f.wt)
0.0 1.103 1.222 1.333 1.219 1.251 1.303 1.464 1.339
4.7 0.859 0.978 1.044 0.960 0.831 0.925 1.262 1.006
9.4 0.496 0.608 0.624 0.576 0.711 0.856 0.908 0.825
14.1 0.485 0.538 0.602 0.542 0.655 0.719 0.765 0.713
Mean 0.736 0.837 0.901 0.824 0.862 0.951 1.100
LSD at 5% A: 0.031 B:0.027 AB: 0.053 A: 0.053 B: 0.046 AB: 0.092
Chlorophyll b (mg g-1f.wt)
0.0 0.452 0.494 0.546 0.497 0.517 0.591 0.664 0.591
4.7 0.332 0.414 0.454 0.400 0.342 0.505 0.603 0.483
9.4 0.193 0.337 0.393 0.308 0.260 0.313 0.340 0.304
14.1 0.190 0.223 0.225 0.213 0.190 0.289 0.297 0.259
Mean 0.292 0.367 0.405 0.327 0.425 0.476
LSD at 5% A: 0.031 B: 0.027 AB: 0.053 A: 0.044 B: 0.038 AB:0.075
Carotenoid (mg g-1f.wt)
0.0 1.074 1.086 1.128 1.096 1.122 1.129 1.130 1.127
4.7 0.739 1.019 1.025 0.928 0.928 1.053 1.116 1.032
9.4 0.620 0.670 0.963 0.751 0.838 1.005 1.040 0.961
14.1 0.614 0.639 0.640 0.631 0.791 0.890 0.983 0.888
Mean 0.762 0.854 0.939 0.920 1.019 1.067
LSD at 5% A: 0.031 B: 0.027 AB: 0.053 A: 0.053 B: 0.046 AB: 0.092
K-Si: Potassium silicate AMF: Arbuscular mycrrohizae fungi
Mineral Content
The applied salinity levels caused gradual increases in Na+ and Cl percentages accompanied by gradual decreases in Ca+2 and K+ percentages as well as ratios of K+ /Na+ and Ca+2/Na+ relative to the control plants (unstressed) (Fig 3). Concerning K-Si and AMF effects on mineral content, it was found increases in the percentages of K+ and Ca+2 as well as ratios of K+ /Na+ and Ca+2/Na+ relative to unstressed plants. K+ /Na+ ratio in plants under saline conditions is considered as one of the important selection criteria for salt tolerance (Ashraf and Harris, 2004). Furthermore, the maintenance of Ca2+ acquisition and transport under salinity constitutes an important determinant of salinity tolerance (Unno et al., 2002), making plants to be less susceptible to osmotic and specific ion injury. Data illustrated in Table 6 and Fig. 3 showed that K-Si nutrition as well as mycorrhizal inoculations improved nutrient contents significantly in both the seasons. However, mycorrhization led to higher uptake of N, P and Ca under salt stress when compared with K-Si nutrition. The role of potassium silicate to decrease sodium concentrations could be explained by inhibited the Na+ transportation to shoot of plants by its effect on transpiration movement (Yeo et al., 1999) or by making a complex with Na+ (Ahmad et al.,1992). Moreover, Liang (1999) told that the salt tolerance due to Si application is attributed to selective uptake and transport of K+ and Na+ by plants. Si negatively correlated with Na+, thus it reduced the concentration of Na+ in thevetia plant, that is a good indicator of salt tolerance in plants. Si uptake is positively correlated with K+ and negatively with Na+ uptake (Ali et al., 2009). Reduction in Na content along with the improvement in K and Ca uptake resulted in higher K /Na and Ca/Na ratio (Fig.3) under both K-Si or AMF inoculations in stressed plants as well as unstressed plants. High Ca2+ has a positive effect on toxic effects of salinity by facilitating higher K+/Na+ selectivity leading to salt adaptation (Rabie and Almadini, 2005). Mycorrhizal treated plants showed reduced accumulation of Na and enhanced content of N, P, K and Ca than non-mycorrhizal plants. AM inoculated plants have higher K/Na and Ca/Na ratio due to an increase of K and Ca uptake in shoot. This results indicated that AMF may act as buffers from toxic conditions (Audet and Charest 2006). The application of ant salinity (arbuscular mycorrhizal fungi or potassium silicate) not can only alleviate the harmful effect of salinity during growth of T.peruviana but might also increase nutrients uptake from soils and prevent Na+ translocation to shoot tissues. Mahmoud et al., (2008) and Aly et al.(2009).
Table (6): Effect of applied treatments on nitrogen and phosphor of T.peruviana irrigated with different levels of water salinity.
Salinity levels
(dSm-1) A First season Second season
Treatments (B)
control K-Si AMF Mean control K-Si AMF Mean
Nitrogen %
0.0 3.643 4.758 5.212 4.538 3.834 4.968 5.642 4.815
4.7 2.111 2.214 2.244 2.190 2.311 2.416 2.545 2.424
9.4 1.095 1.711 1.955 1.587 1.295 1.822 2.061 1.726
14.1 0.966 1.625 1.669 1.420 1.001 1.717 1.799 1.506
Mean 1.954 2.577 2.770 2.110 2.731 3.012
LSD at 5% A: 0.044 B: 0.038 AB: 0.076 A: 0.031 B: 0.027 AB: 0.054
Phosphor %
0.0 0.351 0.334 0.377 0.354 0.355 0.338 0.381 0.358
4.7 0.324 0.387 0.392 0.368 0.329 0.390 0.399 0.373
9.4 0.300 0.329 0.357 0.329 0.310 0.333 0.361 0.335
14.1 0.262 0.296 0.301 0.286 0.264 0.299 0.303 0.289
Mean 0.309 0.337 0.357 0.315 0.340 0.361
LSD at 5% A: 0.044 B: 0.039 AB: 0.076 A: 0.031 B: 0.027 AB:0.054
K-Si: Potassium silicate AMF: Arbuscular mycrrohizae fungi
Fig (3) : Effect of applied treatments on K/Na and Ca/Na of T.peruviana irrigated
with different levels of water salinity.
Proline, Protein, carbohydrates and Phenol / Indol
Proline is a major osmoprotectant osmolyte, which is synthesized by many plants in response to salinity stress, and thereby help in maintaining the osmotic status of the cell to ameliorate the abiotic stress effect (Yoshiba et al.,1997). In Ephedra aphylla (Alqarawi et al.,2014a) accumulation of proline leads to salinity stress amelioration through better extraction of water from the soil solution by its active role in osmotic adjustment. The results related to the effect of different concentrations of NaCl on proline in T. peruviana are presented in Table 7. Salinity at concentration 4.7, 9.4 and 14.1 dSm-1 significantly increased the proline contents in T. peruviana to 20.6%, 31.0%, and 44.9%, respectively, as compared to control (unstressed plants), further, increase in proline, was observed in directly proportional with salt stress. Whereas application of K-Si or AMF have shown further decrease in proline content means that K-Si and AMF decreased the adverse effect of salinity in T. peruviana.
Phenol is on line as the proline, salinity stress increased phenol content, accumulation of phenolic compounds consider as another important strategy for avoiding the induced of salt stress. Phenols are secondary metabolites implicated in plant protection and have been recognized for their antioxidant property (Abdel Latef et al.,2016). The improvement in thevetia plants growth reflected in phenol/Indol ratio (Fig. 4) under both K-Si or AMF treatments in stressed plants. Improved phenol content support better growth. On the other hand, decreases in indole compounds under the effect of salinity stress (Fig. 4) were concurrent with the decrease in vegetative growth parameters as affected by salinity stress (Tables 2, 3, 4). The effect of AM-fungi and K-Si treatments on protein and carbohydrates, Table 7 reveal that, treatments showed an increase as compared to the control in both seasons. The highest values of protein and carbohydrates were found by mycorrhizal treatment in both seasons.
Carbohydrates are supplied mainly through the process of photosynthesis and photosynthetic rates are usually lower in plants under salinity stress (Ashraf and Harris, 2004). Hence, the reduction in photosynthetic pigments in T.peruviana leaves under the effect of irrigation water salinity stress (Table 5) might have led to decreased levels of photo-assimilates in the leaves, mainly total carbohydrates (Table 7). On the other hand, anti-salinity treatments (AMF or K-Si) enhancement effects on photosynthetic pigments that might interpret the overproduction of total carbohydrates, and thus enhancement of plant growth. AMF has a regulatory and stimulatory influence on protein, proline, and carbohydrates synthesis and these solutes may play a role in osmotic adjustment that helps plant to grow normally under salinity.
The effect of AM-fungi and K-Si treatments on protein and carbohydrates, (Table 7) reveal that all treatments showed an increase as compared to the control in both seasons. The highest values of protein and carbohydrates were found by mycorrhizal treatment in both seasons. AMF has a regulatory and stimulatory influence on protein, proline and carbohydrates synthesis and these solutes may play a role in osmotic adjustment that helps plant to grow normally under salinity.
The obtained results in this study are in agreement with those obtained by Zaki et al. (2009) and Bashan et al.(2006), they found increases in photosynthetic pigments (chl. a, b and carotenoids), crude protein, soluble sugar, polysaccharide in broccoli and wheat plants respectively .The parallel increase in the content of nutrients, photosynthetic pigments, reducing proline and phenol in inoculated plants might be responsible for plants counteracting oxi-dative damage generated by salinity (El-Amri et al., 2013).
Table (7): Effect of applied treatments on Proline, protein and Total carbohydrates of T.peruviana irrigated with different levels of water salinity.
Salinity levels
(dSm-1) A First season Second season
Treatments (B)
control K-Si AMF Mean control K-Si AMF Mean
Proline (”mol g-1 f.wt)
0.0 0.223 0.187 0.107 0.172 0.232 0.200 0.157 0.196
4.7 0.281 0.244 0.238 0.254 0.290 0.263 0.248 0.267
9.4 0.323 0.262 0.249 0.278 0.363 0.271 0.261 0.298
14.1 0.405 0.299 0.288 0.331 0.456 0.340 0.290 0.362
Mean 0.308 0.248 0.221 0.335 0.269 0.239
LSD at 5% A: 0.031 B: 0.027 AB: 0.054 A: 0.044 B: 0.038 AB: 0.076
Protein %
0.0 22.77 29.74 32.58 28.36 23.96 31.05 35.26 30.09
4.7 13.19 13.84 14.03 13.69 14.44 15.10 15.91 15.15
9.4 6.84 10.69 12.22 9.92 8.09 11.39 12.88 10.79
14.1 6.04 10.16 10.43 8.87 6.26 10.73 11.24 9.414
Mean 12.21 16.11 17.31 13.19 17.07 18.82
LSD at 5% A: 0.05 B: 0.04 AB: 0.09 A: 0.06 B: 0.05 AB: 0.11
Total carbohydrates %
0.0 5.585 6.770 8.664 7.006 7.857 8.548 9.037 8.481
4.7 5.242 5.273 5.493 5.336 5.921 6.257 6.434 6.204
9.4 3.147 4.100 4.607 3.951 4.350 5.346 5.756 5.151
14.1 3.238 3.464 3.747 3.483 4.124 4.405 4.998 4.509
Mean 4.303 4.902 5.628 5.563 6.139 6.556
LSD at 5% A: 0.031 B: 0.027 AB: 0.053 A: 0.053 B: 0.046 AB: 0.092
K-Si: Potassium silicate AMF: Arbuscular mycrrohizae fungi
Fig (4): Effect of applied treatments on Phenol / Indol of T.peruviana irrigated with different levels of water salinity.
Finally, it could be concluded that NaCl stress negatively affects growth and biomass yield and other physiological parameters; however, ant salinity treatments (AM-fungi or K-Si) mitigates the negative effect and seem to enhance plant growth through the accumulation of different solutes and enhanced enzymes activity. So, we recommend using the applied treatments (arbuscular mycorrhizal fungi and potassium silicate) in Thevetia peruviana cultivars subjected to salinity stress.
REFEREENCES
Abbas, T.; Balal, R. M.; Shahid, M. A.; Pervez, M. A.; Ayyub, C. M.; Aqueel, M. A. and Javaid, M. M. (2015). Silicon-induced alleviation of NaCl toxicity in okra (Abelmoschus esculentus) is associated with enhanced photosynthesis, osmoprotectants and antioxidant metabolism. Acta Physiol. Plant, 37: 6
Abdel-Fattah, G. M.; El-Dohlob, S. M.; El-Haddad, S.A.; Hafez, E. E. and Rashad, Y. M. (2010). An ecological view of arbuscular mycorrhizal status in some Egyptian plants. J. Environ. Sci., 37:123-136.
Abdel-Fattah, G. M. and Asrar, A. A. ( 2012). Arbuscular mycorrhizal fungal application to improve growth and tolerance of wheat (Triticum aestivum L.) plants grown in saline soil. Acta Physiol. Plant, 166: 268-281.
Abdel Latef, A. A. H.; Jan, S.; Abd_Allah, E. F.; Rashid, B.; John, R. and Ahmad, P. (2016). ‘Soybean Under Abiotic Stress: proteomic approach,’ in Plant-Environment Interaction: Responses and Approaches to Mitigate Stress, M. M. Azooz and P. Ahmad, Eds., John Wiley & Sons, New York, NY, USA, 1st edition, chapter 2.
Ahanger, M. A.; Hashem, A.; Abd-Allah, E. F. and Ahmad, P. (2014). Arbuscular mycorrhiza in crop improvement under environmental stress,’ in Emerging Technologies and Management of Crop Stress Tolerance, P. Ahmad and S. Rasool, Eds., Academic Press, New York, NY, USA, 2: 69’95.
Ahmad, R.; Zaheer, S. and Ismail, S. (1992). Role of silicon in salt tolerance of wheat (Triticum aestivum L.). Plant Sci., 85: 43-50.
Al-aghabary, K.; Zhu, Z. J. and Shi, Q. H. (2004). Influence of silicon supply on chlorophyll content, chlorophyll fluorescence, and antioxidative enzyme activities in tomato plants under salt stress. J Plant Nutr., 27:2101’2115.
Ali, A.; Basra, S. M. A.; Ahmad, R. and Wahid, A. (2009). Optimizing silicon application to improve salinity tolerance in wheat. Soil & Environ., 28(2): 136-144.
Aliasgharzadeh, N.; Rastin, N. S.; Towfighi, H. and Alizadeh, A. (2001). Occurrence of arbuscular mycorrhizal fungi in saline soils of the Tabriz Plain of Iran in relation to some physical and chemical properties of soil. Mycorrhiza, 11:119’122.
Ali, E. F.; Bazaid, S. A. and Hassan, F. A. S. (2014). Salinity Tolerance of Taif Roses by Gibberellic Acid (GA3). Inter. J. of Sci. and Res., 3(11): 184-192.
Ali, Hanan M. H. and Attia, Mona G (2015). Response of salt stressed rosemary plants to antistress agents. Sci. J. of Flowers and Orn. Plants, 2(3) 249-264.
Aly, M. H.; Zeiniab, R. M. and Osman, A. M. H. (2009). Effect of seed inoculation and foliar application with Azospirillum brasiliense and/or Bacillus polymyxa on productivity and quality of sugar beet. Egypt. J. Appl. Sci.,24 (2A): 56-70.
Alqarawi, A.; Abd Allah, E. and Hashem, A. (2014 a). Alleviation of salt-induced adverse impact via mycorrhizal fungi in Ephedra aphylla Forssk. J. of Plant Interactions, 9 (1): 802’810.
Alqarawi, A. A.; Abeer, Hashem; Abd-Allah, E. F.; Alshahrani, T. S. and Huqail, A. A. (2014 b). Effect of salinity on moisture content, pigment system and lipid composition in Ephedra alata Decne. Acta Biol. Hung., 65: 61’71.
A.O.A.C. (2000). Official Methods of Analysis 16th Ed. A.O.A.C. Benjamin Franklin Station, Washington, D.C., S.A. 490-510.
Aroca, R.; Ruiz-Lozano, J. M.; Zamarreno, A. M.; Paz, J. A.; Garcia-Mina, J. M.; Pozo, J. M. and Lopez-Raez, J. A. (2013). Arbuscular mycorrhizal symbiosis influences strigolactone production under salinity and alleviates salt stress in lettuce plants. J. Plant Physiol., 170: 47’55.
Ashraf, M. and Harris, P. (2004). Potential biochemical indicators of salinity tolerance in plants. Plant Sci.,166: 3-16.
Asrar, A. A.; Abdel-Fattah, G. M.; Elhindi, K. M. and Abdel-Salam, A. (2014). The impact of arbuscular mychorrhizal fungi in improving growth, flower yield and tolerance of kalanchoe (Kalanchoe blossfeldiana Poelin) plants grown in NaCl-stress conditions. Food Agric. Environ., 12: 105-112.
Assefat, Lateifa S. (2006). Effect of biofertilization and salinity levels on Khaya senegalensis plant. Ph. D. Thesis, Fac. Agric., Cairo Univ.
Audet, P. and Charest, C. (2006). Effects of AM colonization on ‘wild tobacco’ plants grown in zinc-contaminated soil. Mycorrhiza, 16:277’283.
Balakhnina, T. I.; Bulak, P.; Matichenkov, V. V.; Kosobryukhov, A. A. and W”odarczyk, T. M. (2015). The influence of Si-rich mineral zeolite on the growth processes and adaptive potential of barley plants under cadmium stress. Plant Growth Regul., 75:557’565.
Bates, L. S.; Waldren, R. P. and Teare, I. D. (1973). Rapid determination of free proline of water stress studies. Plant and Soil, 39: 205’207.
Bashan, Y.; Bustillos, J. J.; Leyva, L. A.; Hernandez, J. P. and Bacilio, M. (2006). Increase in auxillary photoprotective photosynthetic pigments in wheat seedlings induced by Azospirillum brasilense. Biol. Fertil. Soils, 42: 279- 285.
Bayat, H.; Alirezaie, M.; Neamati, H. and Saadabad, A. A. (2013). Effect of Silicon on Growth and Ornamental Traits of Salt-stressed Calendula (Calendula officinalis L.) J. of Orna. Plants, 3 (4): 207-214.
Bhosale, K. S. and Shinde, B. P. (2011). Influence of arbuscular mycorrhizal fungi on proline and chlorophyll content in Zingiber officinale Rosc grown under water stress. Indian J. Fundam Appl. Life Sci., 1:172’176.
Bothe, H. (2012). Arbuscular mycorrhiza and salt tolerance of plants. Symbiosis, 58:7’16.
El-Amri, S. M.; Al-Whaibi, M. H.; Abdel-Fattah, G. M. and Siddiqui, M. H. (2013). Role of mycorrhizal fungi in tolerance of wheat genotypes to salt stress. Afr. J. Microb. Res., 7(14):1286-1295.
El-Sayed, A. A. E. (2013). Effect of soil type, fertilization and salinity on growth and constituents of Moringa oleifera Lam. M Sc. Thesis, Fac. Agric., Cairo Univ.
El-Zait, Rasha A. M. (2011). Effect of irrigation water salinity and gibberellic acid treatments on vegetative growth and chemical composition of Conocarpus erectus plant. M Sc. Thesis, Fac. Agric., Cairo Univ.
Fernanda, C.; Echeverr”a, H. E. and Pagano, M. C. (2012). Arbuscular mycorrhizal fungi: Essential belowground organisms for earth life but sensitive to a changing environment. Afr. J., Microbiol. Res., 6: 5523-5535.
Garg, N. and Chandel, S. (2015). Role of arbuscular mycorrhiza in arresting reactive oxygen species (ROS) and strengthening antioxidant defense in Cajanus cajan (L.) Millsp. nodules under salinity (NaCl) and cadmium (Cd) stress. Plant Growth Regul, 75: 521’534.
Giri, B. R.; Kapoor, K. G. and Mukerji (2003). Influence of arbuscular mycorrhizal fungi and salinity on growth, biomass and mineral nutrition of Acacia auriculiformis. Biol. Fertil. Soils, 38: 170-175.
Giri, B. R.; Kapoor, K. G. and Mukerji (2007). Improved tolerance of Acacia nilotica to salt stress by arbuscular mycorrhiza Glomus fasciculatum may be partly related to elevated K/Na ratios in root and shoot tissues. Microbial Ecol., 54: 753-760.
Gong, H. J.; Randall, D. P. and Flowers, T. J. (2006). Silicon deposition in root reduces sodium uptake in rice (Oryza sativa L.) seedlings by reducing bypass flow. Plant Cell Environ, 29:1970’1979.
Guan, Z. J.; Luo, Q.; Chen, X.; Feng, X. W.; Tang, Z. X.; Wei, W. and Zheng, Y. R. (2014). Saline soil enzyme activities of four plant communities in Sangong River basin of Xinjiang, China. J. of Arid Land, 6 (2): 164’173.
Gunes, A.; Ali, I.; Bagci, E. G. and Pilbeam, D. J. (2007). Silicon-mediated changes of some physiological and enzymatic parameters symptomatic for oxidative stress in spinach and tomato grown in sodic-B toxic soil. Plant Soil 290:103’114.
Hasegawa, P. M.; Bressan, R. A.; Zhu, J. K. and Bohnert, J. K. (2000). Plant cellular and molecular response to high salinity. Ann Rev of Plant Physiol and Plant Mole Biol., 51:463-499.
Herbert, D.; Philips, P. J. and Strange, R. E. (2005). Determination of total carbohydrates. Methods in Microbiology, 58: 209-344.
Heikham, E., Rupam K.,y Bhoopander,G.(2009). Arbuscular mycorrhizal fungi in alleviation of salt stress: a revie. En: Annals of Botany, 104 (7): 1263-1280.
Iqbal, M. and Ashraf, M. (2013). Alleviation of salinity-induced perturbations in ionic and hormonal concentrations in spring wheat through seed preconditioning in synthetic auxins. Acta Physiol Plant, 35:1093’1112.
Juniper, S. and Abbott, L.K. (2006). Soil salinity delays germination and limits growth of hyphae from propagules of arbuscular mycorrhizal fungi. Mycorrhiza, 16: 371-379.
Kafi, M. and Rahimi, Zainab (2011). Effect of salinity and silicon on root characteristics, growth, water status, proline content and ion accumulation of purslane (Portulaca oleracea L.) Soil Sci. and Plant Nutri., 57: 341-347.
Larsen, P.; Harbo, A.; Klungsoyr, S. and Aasheim, T. (2006). On the biogenesis some indoles compounds in Acetobacter xylinum. Physio. Plantarum, 15(3): 552-565.
Lemanowicz, J. and Krzy”aniak, M. (2015). Vertical distribution of phosphorus concentrations, phosphatase activity and further soil chemical properties in salt-affected Mollic Gleysols in Poland. Environ. Earth Sci., 74 (3): 2719’2728.
Liang, Y. C. (1999). Effect of silicon on enzyme activity and sodium, potassium and calcium concentration in barley under salt stress. Plant Soil, 209: 217-224.
Lu, N.; Yu, M.; Cui, M.; Luo, Z.; Feng, Y.; Cao, S.; Sun, Y. and Li, Y. (2016). Effects of Different Ectomycorrhizal Fungal Inoculates on the Growth of Pinus tabulaeformis Seedlings under Greenhouse Conditions. Forests, 7, 316 1-14.
Manivannan, A.; Soundararajan, P.; Arum, L. S.; Ko, C. H.; Muneer, S. and Jeong, B. R. (2015). Silicon-Mediated Enhancement of Physiological and Biochemical Characteristics of Zinnia elegans ‘Dreamland Yellow’ Grown under Salinity Stress. Hortic. Environ. Bio., 56 (6): 721-731.
Mahmoud, A.R.; Magda, M.; Hafez, A.A.A. and Abd-El-Baky, M.M.H. (2008). Response of okra plants (Hibiscus esculentus L.) to spraying with zinc sulphate and levels of nitrogen application. Egypt. J. Appl. Sci., 23(12A): 296-303.
Mead, R.; Curnow, R. N. and Harted, A. M. (1993). Statistical Methods in Agricultural and Experimental Biology. 2nd Ed. Chapman and Hal, London, 10-44.
Moran, R. and Porath, D. (1980). Chlorophyll determination in intact tissues using NN-dimethyl formamid. Plant Physiol., 65: 478-479.
Rabie, G. H. and Almadini, A. M. (2005). Role of bioinoculants in development of salt-tolerance of Vicia faba plants under salinity stress. Afr. J. Biotechnol., 4: 210-222.
Ramos Silva, A., Tavares-Carre”n, F.; Figueroa, M.; Torre-Zavala, S. D. l.; Gastelum-Arellanez, A.; Rodr”guez-Garc”a, A.; Gal”n-Wong L. J. and Avil”s-Arnaut, H. (2017). BMC Complementary and Alternative Medicine. 17:241.
Romero-Aranda, M. R.; Jurado, O. and Cuartero, J. (2006). Silicon alleviates the deleterious salt effect on tomato plant growth by improving plant water status. J Plant Physiol., 163:847’855.
Sabir, P.; Ashraf, M.; Hussain, M. and Jamil, A. (2009). Relationship of photosynthetic pigments and water relations with salt tolerance of proso millet (Panicum Miliaceum L.) accessions Pak. J. Bot., 41: 2957-2964.
Sheng, M.; Tang, M.; Chan, H.; Yang, B.; Zhang, F. and Huang, Y. (2008). Influence of arbuscular mycorrhizae on photosynthesis and water status of maize plants under salt stress. Mycorrhiza, 18:287’296.
Siddikee, M. A.; Tipayno, S. C.; Kim, K.; Chung, J. and Sa, T. (2011). Influence of varying degree of salinity-sodicity stress on enzyme activities and bacterial populations of coastal soils of Yellow Sea, South Korea. J. of Microbio. and Biotech., 21(4): 341’346.
Tian, C.Y.; Feng, G.; Li, X. L. and Zhang, F. S. (2004). Different effects of arbuscular mycorrhizal fungal isolates from saline or non-saline soil on salinity tolerance of plants. App Soil Ecol., 26:143’148.
Unno, H.; Maeda, Y.; Yamamoto, S.; Okamoto, M. and Takenaga, H. (2002). Relationship between salt tolerance and Ca retention among plant species. Japan J. Soil Sci. Plant Nut., 73: 718-725.
Walinga, I.; Van Der Lee, J. J.; Houba, V. J. G.; Van Vark, W. and Novozamsky, I. (1995). Plant Analysis Manual. Shapter 2.
Watfa, R. A. (2009). Effect of soil media, nutrition and mycorrhiza fungi on growth and chemical composition of carob and Aleppo pine seedlings. M. Sc. Thesis, Fac. Agric. Cairo Univ.
Yamato, M.; Ikeda, S. and Iwase, K. (2008). Community of arbuscular mycorrhizal fungi in a coastal vegetation on Okinawa island and effect of the isolated fungi on growth of sorghum under salt-treated conditions. Mycorrhiza, 18:241’249.
Yeo, A. R.; Flowers, S. A.; Rao, G.; Welfare, K.; Senanayake, N. and Flowers, T. J. (1999). Silicon reduces sodium uptake in rice (Oryza sativa L.) in saline conditions and this is accounted for by reduction in transpirational bypass flow. Plant Cell Environment, 22: 559-565.
Yoshiba, Y. ,T. Kiyosue, K. Nakashima, K. Yamaguchi-Shinozaki (1997). Regulation of levels of proline as an osmolyte in plants under water stress. Plant Cell Physiol., 38: 1095-1102.
Zaki, M. F.; Abdel-hafez, A. A. M. and Camilia, Y. E. (2009). Influence of biofertilization and nitrogen sources on growth, yield and quality of Broccoli (Brassica cleracea var. Italica). Egypt. J. Appl. Sci., 24: 86-111.
Zhu, Y. and Gong, H. (2014). Beneficial effects of silicon on salt and drought tolerance in plants. Agron Sustain Dev., 34(2):455’472.
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