The seeds were surface sterilized and then soaked for two hours and sown in soil mixture having 3 parts of garden soil, 1 part of sand and 1 part of manure. The experiment was carried out in earthen pots of uniform size each containing 5 Kg of the soil mixture. Before sowing, the soil was amended with K₂CrO₄ for Cr treatments (0 µM/Kg), and Na₂SeO₄ for Se treatments (0 µM/Kg), both alone and in combinations. The concentration used for Cr was 50% inhibitory concentration (IC50), while for Se, the most stimulatory concentrations as observed from preliminary studies were used. The pots were kept in natural environmental conditions and were watered regularly. The experiment was conducted in triplicates. The harvesting of the plants was done after 30 days of sowing and stored at -20 ℃ . Some harvested plants were also dried by keeping them in hot air oven for 24 h at 80 ℃.

Se application aided in improving plant growth, reducing the oxidative damage and strengthening the antioxidative defence system in plants raised in soils with binary combinations of Cr and Se. Photosynthesis, which is one of the vital physiological processes, was positively influenced with application of Se. It helped in minimising the toxicity of Cr and enhanced the contents of pigments. The efficiency of photosynthetic machinery was further strengthened by the increase of net photosynthetic rate, transpiration rate, stomatal conductance and intercellular CO₂ concentration, and hence indicated its importance in combating stress. The study also highlighted the role of Se in enhancing the contents of secondary metabolites which play an important role in heavy metal chelation, complex formation and ROS scavenging, thereby reducing the chances of Cr to cause physiological damage.

A significant modulation in gene expression was observed in B. juncea in response to Cr and Se. The gene responsible for H₂O₂ production is respiratory burst oxidase (RBO) which showed a significant upregulation in its expression by 3.63 folds in response to Cr treatment. Se at 2 µM/Kg in combination with 300 µM/Kg Cr caused decrease by 1.62 folds in the expression of RBO gene.An increase in expression was observed SOD, CAT and GST-1 by 2.75 folds, 2.82 folds and 2.03 folds respectively in response to Cr. However, Cr treatment resulted in a reduction of relative expression of POD and GR genes by 0.54 and 0.61 folds respectively in leaves of B. juncea plants. The combined treatment of Se and Cr aided in reducing Cr toxicity by increasing the expression of genes coding all these enzymes. Maximum increase in expression in case of CAT (4.68 folds), GR (2.08 folds) and GST-1 (2.98 folds) was observed at binary combination of 4 µM/Kg Se and 300 µM/Kg Cr. For SOD, 4.25 folds increase in gene expression was observed at 6 µM/Kg Se and 300 µM/Kg Cr. The expression of POD enhanced by 1.75 folds at the concentration of 2 µM/Kg Se and 300 µM/Kg Cr. The genes coding forcholrophyllase (CHLASE) chalcone synthase (CHS) and phenylalanine ammonialyase (PAL) showed enhanced expression of 2.47 folds, 1.79 folds and 2.07 folds respectively in the plants raised in Cr spiked soils. The co-application of Se and Cr helped in increasing the expression of CHS and PAL, while aided in reducing the expression of CHLASE. The concentration of 4 µM/Kg for Se proved to be most beneficial for enhancing the gene expression of PAL by 3.92 folds, while the same concentration caused a decline in the expression of CHALSE by 1.65 folds. However, for CHS expression, 6 µM/Kg Se caused an increase by 2.52 folds. Statistical analysis by one-way ANOVA and MLR supported the observations. The values of beta-regression coefficients for Se indicated the stress alleviating effects of Se for all the genes.

The experiment was conducted in a 'shade'-type greenhouse with 30% shade at the Instituto de Investigaciones Agropecuarias y Forestales (IIAF), Universidad Michoacana de San Nicolas de Hidalgo (UMSNH), Morelia, Michoacan, Mexico. Maximum and minimum temperatures in the greenhouse varied between 28 and 32 ℃ and between 8 and 18 ℃ respectively. Plants of the strawberry cultivar 'Aromas' were used that had previously been grown in a sterilised (95 ℃ water/steam, 40 min) substrate of coconut fibre/perlite (1:3 v/v) under greenhouse conditions. Before the experiment was established, the absence of AMF in the roots was verified by the ink and vinegar technique, modifying the duration of immersion in KOH and ink/vinegar solution (7 and 5 min respectively). Before planting, roots were disinfected by submerging them for 20 s in 20 g/L sodium hypochlorite solution and rinsing them in water. The inoculum was prepared with spores of Glomus intraradices cultivated in liquid medium (3.5 × 10⁶ spores/L, 90% viability; Premier Tech Biotechnologies Company, Quebec, Canada), which was diluted with fitagel (Sigma P-8169, Saint Louis, MO, USA) solution at 50 g/L to obtain a final concentration of about 5 × 10⁴ spores/L. The viability of spores was determined according to the method of An and Hendrix. Eighteen days after setting up the experiment, each plant received 2 mL of inoculum applied directly to the recently formed roots. One month later, after staining, the percentage of root colonisation was determined by the gridline intersect method. The experiment was organised as a full factorial, completely randomised design with two factors: inoculation (two levels: mycorrhizal and non-mycorrhizal plants) and N concentration in the nutrient solution (three levels: 3, 6 and 18 mmol/L). The six treatments were replicated four times, producing 24 experimental units with ten plants each. Every second day, all plants were irrigated up to substrate saturation. Nitrogen was supplied as NO and the cation/anion ratio was kept constant by varying the concentration of SO. When N was below 18 mmol/L, the cation concentrations were maintained as follows: K+, 3; Ca²⁺, 3.5; Mg²⁺, 1.5 mmol/L. They were increased in the 18 mmol/L N treatment: K+, 6.5; Ca²⁺, 7.5; Mg²⁺, 3.25 mmol/L. In all nutrient solutions the concentration of phosphorus (P) was 0.3 mmol/L. The other nutrients in the solutions were: H₃BO₃, 20; CuSO₄. 5H₂O, 0.5; Fe-EDTA (Ethylenediaminetetraacetic acid iron (III) sodium salt), 15; MnSO₄.H₂O, 12; (NH₄)₆Mo₇O₂₄ . 4H₂O, 0.05; ZnSO₄ . 7H₂O, 3 µmol/L. The pH was adjusted to 5.5 at every application date.

Mycorrhization did not modify the weight, diameter or length of strawberry fruits but had a negative effect on most colour parameters. Moreover, fruits of mycorrhizal plants had higher K and Cu concentrations and showed greater accumulation of most phenolic compounds.

Three species of arbuscular mycorrhizal fungi namely, Glomus mosseae, G. fasciculatum and G. intraradices and a mixture of all three species procured from Turan Biotech Co., Shahroud, Iran, were utilized. The rooted vines were transplanted in 8 l plastic pots in 1:1 fine sand:leaf mold. While transplanting, inoculation was performed by incorporating 100 g expanded clay containing spores, mycelium, and infected/colonized Trifolium repens L. root fragments near the roots of each plant. The control plants were not inoculated. The plants were kept in greenhouse at 35/25 ℃ day/night temperatures and 70% relative humidity. Ninety days after inoculation AMF root colonization was confirmed by staining fresh root segments, according to procedure suggested by Phillips and Hayman (1970). Fresh grape leaf and stem tissues (Vitis vinifera L.) were harvested from the inoculated and non-inoculated vines and transferred to the laboratory for analysis.

Grape plants inoculated with AMF (Glomus sp.) would make higher quercetin content than non-mycorrhizal grape plants. However, the response was found to be depending on grape genotype.

Three species of arbuscular mycorrhizal fungi namely, Glomus mosseae, G. fasciculatum and G. intraradices and a mixture of all three species procured from Turan Biotech Co., Shahroud, Iran, were utilized. The rooted vines were transplanted in 8 l plastic pots in 1:1 fine sand:leaf mold. While transplanting, inoculation was performed by incorporating 100 g expanded clay containing spores, mycelium, and infected/colonized Trifolium repens L. root fragments near the roots of each plant. The control plants were not inoculated. The plants were kept in greenhouse at 35/25 ℃ day/night temperatures and 70% relative humidity. Ninety days after inoculation AMF root colonization was confirmed by staining fresh root segments, according to procedure suggested by Phillips and Hayman (1970). Fresh grape leaf and stem tissues (Vitis vinifera L.) were harvested from the inoculated and non-inoculated vines and transferred to the laboratory for analysis.

Grape plants inoculated with AMF (Glomus sp.) would make higher quercetin content than non-mycorrhizal grape plants. However, the response was found to be depending on grape genotype.

Three species of arbuscular mycorrhizal fungi namely, Glomus mosseae, G. fasciculatum and G. intraradices and a mixture of all three species procured from Turan Biotech Co., Shahroud, Iran, were utilized. The rooted vines were transplanted in 8 l plastic pots in 1:1 fine sand:leaf mold. While transplanting, inoculation was performed by incorporating 100 g expanded clay containing spores, mycelium, and infected/colonized Trifolium repens L. root fragments near the roots of each plant. The control plants were not inoculated. The plants were kept in greenhouse at 35/25 ℃ day/night temperatures and 70% relative humidity. Ninety days after inoculation AMF root colonization was confirmed by staining fresh root segments, according to procedure suggested by Phillips and Hayman (1970). Fresh grape leaf and stem tissues (Vitis vinifera L.) were harvested from the inoculated and non-inoculated vines and transferred to the laboratory for analysis.

Grape plants inoculated with AMF (Glomus sp.) would make higher quercetin content than non-mycorrhizal grape plants. However, the response was found to be depending on grape genotype.

Three species of arbuscular mycorrhizal fungi namely, Glomus mosseae, G. fasciculatum and G. intraradices and a mixture of all three species procured from Turan Biotech Co., Shahroud, Iran, were utilized. The rooted vines were transplanted in 8 l plastic pots in 1:1 fine sand:leaf mold. While transplanting, inoculation was performed by incorporating 100 g expanded clay containing spores, mycelium, and infected/colonized Trifolium repens L. root fragments near the roots of each plant. The control plants were not inoculated. The plants were kept in greenhouse at 35/25 ℃ day/night temperatures and 70% relative humidity. Ninety days after inoculation AMF root colonization was confirmed by staining fresh root segments, according to procedure suggested by Phillips and Hayman (1970). Fresh grape leaf and stem tissues (Vitis vinifera L.) were harvested from the inoculated and non-inoculated vines and transferred to the laboratory for analysis.

Grape plants inoculated with AMF (Glomus sp.) would make higher quercetin content than non-mycorrhizal grape plants. However, the response was found to be depending on grape genotype.

Three species of arbuscular mycorrhizal fungi namely, Glomus mosseae, G. fasciculatum and G. intraradices and a mixture of all three species procured from Turan Biotech Co., Shahroud, Iran, were utilized. The rooted vines were transplanted in 8 l plastic pots in 1:1 fine sand:leaf mold. While transplanting, inoculation was performed by incorporating 100 g expanded clay containing spores, mycelium, and infected/colonized Trifolium repens L. root fragments near the roots of each plant. The control plants were not inoculated. The plants were kept in greenhouse at 35/25 ℃ day/night temperatures and 70% relative humidity. Ninety days after inoculation AMF root colonization was confirmed by staining fresh root segments, according to procedure suggested by Phillips and Hayman (1970). Fresh grape leaf and stem tissues (Vitis vinifera L.) were harvested from the inoculated and non-inoculated vines and transferred to the laboratory for analysis.

Grape plants inoculated with AMF (Glomus sp.) would make higher quercetin content than non-mycorrhizal grape plants. However, the response was found to be depending on grape genotype.