Contribution of Piriformospora indica on improving the nutritional quality of greenhouse tomato and its resistance against cu toxicity after humic acid addition to soil.

Protected cultivation has a significant contribution in vegetable production. We investigated whether humic acid addition to soil and Piriformospora indica can improve the nutritional quality of greenhouse tomato. We conducted a pot experiment, in which the effects of P. indica inoculation, humic acid addition, and Cu spiking to soil (0, 120, 240, and 500 ppm Cu) were tested. Humic acid addition to soil spiked with 500 ppm Cu decreased the Cu concentration in the fruits of plants inoculated with P. indica from 0.65 to 0.40 mg 100 g Fw-1, which is still above the maximum allowed limits of Cu in tomato by World Health Organization (WHO). The lycopene and ascorbic acid content of tomato fruits were consistently improved by humic acid addition and P. indica inoculation. The antioxidant enzymes' activity changed in response to humic acid addition, Cu spiking to soil, and P. indica inoculation. With increasing Cu level up to 240 ppm, the activity of superoxide dismutase (SOD) and peroxidase (POD) increased significantly. However, with spiking more Cu to soil, the activity of antioxidant enzymes reduced and the MDA content increased significantly. Addition of humic acid to soil and/or presence of P. indica increased the activity of antioxidant enzymes when the soil spiked with 500 ppm Cu. This study indicated that addition of P. indica and humic acid to the soil can enhance the nutritional quality of greenhouse tomato by reduction of Cu toxicity as a common pollutant in the greenhouse media and increasing the antioxidant content of fruits.

Soil-indigenous arbuscular mycorrhizal fungi and zeolite addition to soil synergistically increase grain yield and reduce cadmium uptake of bread wheat (through improved nitrogen and phosphorus nutrition and immobilization of Cd in roots).

Soil pollution with heavy metals is a major problem in industrial areas. Here, we explored whether zeolite addition to soil and indigenous arbuscular mycorrhizal fungi (AMF) can reduce cadmium (Cd) uptake from soil by bread wheat. We conducted a pot experiment, in which the effects of indigenous soil AMF, zeolite addition, and Cd spiking to soil [0, 5, 10, and 15 mg (kg soil)-1] were tested. Zeolite addition to soil spiked with 15 mg Cd kg-1 decreased the Cd uptake to grains from 11.8 to 8.3 mg kg-1 and 8.9 to 3.3 mg kg-1 in the absence and presence of indigenous AMF, respectively. Positive growth, nitrogen (N), and phosphorous (P) uptake responses to mycorrhization in Cd-spiked soils were consistently magnified by zeolite addition. Zeolite addition to soil stimulated AMF root colonization. The abundance of AMF taxa changed in response to zeolite addition to soil and soil Cd spiking as measured by quantitative polymerase chain reaction. With increasing Cd spiking, the abundance of Funneliformis increased. However, when less Cd was spiked to soil and/or when zeolite was added, the abundance of Claroideoglomus and Rhizophagus increased. This study showed that soil-indigenous AMF and addition of zeolite to soil can lower Cd uptake to the grains of bread wheat and thereby reduce Cd contamination of the globally most important staple food.

Health risk assessment of Pb and Cd in soil, wheat, and barley in Shazand County, central of Iran.

BACKGROUND: Heavy metal contamination via mining activity is a serious problem around the world. This study was conducted to evaluate the total non-cancer hazard quotient (THQ) and excess lifetime cancer risks of lead (Pb) and cadmium (Cd) to different population groups via soil, wheat and barley ingestion, soil-dermal contact, and inhalation soil particulates around Shahin mine located in Shazand County. METHODS: Soil and plants were sampled randomly from 60 agricultural fields around Shahin mine. The samples Pb and Cd concentrations were determined using atomic absorption spectroscopy (AAS). The THQ and the excess lifetime cancer risks of Pb and Cd were estimated using the formulas suggested by the U.S. Environmental Protection Agency (USEPA). The Pb non-cancer risk for children (<6 years old) was assessed using the integrated exposure uptake bio-kinetic (IEUBK) model. RESULTS: The mean contents of Pb (234.47 mg kg-1) and Cd (1.89 mg kg-1) in soil samples were higher than the background values. The mean Pb and Cd concentrations in wheat grains were 0.44 and 0.23 µg g-1 respectively, which were about 6.5 and 5.8 times higher than that was observed in barley grains, respectively. The THQ of Pb and Cd for all groups were greater than 1. The excess lifetime cancer risks of Pb via wheat and barley consumption for all receptor groups were greater than 1 × 10-6. CONCLUSIONS: Crop ingestion and soil inhalation had the greatest and lowest portions to increase the THQ and excess lifetime cancer risks of Pb and Cd in the study region, respectively.

Effect of Nano Fe-oxide and Endophytic Fungus (P. indica) on Petroleum Hydrocarbons Degradation in an Arsenic Contaminated Soil under Barley Cultivation.

BACKGROUND: Heavy metals and petroleum hydrocarbon pollution are important environmental problems. This research was conducted to evaluate the effect of nano Fe-oxide and endophytic fungus (P. indica) on petroleum hydrocarbons degradation in an arsenic and petroleum hydrocarbons contaminated soil using barley plant. METHODS: Treatments consisted of the presence (E+) and the absence (E-) of P.indica fungi, soil contaminated with As in the rates of 0 (AS0), 12 (AS12) and 24 (As24) mg As /kg of soil, and application of 0 (Fe0) and 1% (Fe1) (W/W) nano Fe-oxide. The plant used in this study was the barley plant. After 7 weeks, the root and shoot As concentration was measured using atomic absorption spectroscopy. The concentration of total soil petroleum hydrocarbon (TPHS) was measured using GC-mass. RESULTS: Application of nano Fe-oxide in soil treated with 12 and 24 mg As/kg soil decreased root As concentration by 30 and 20.6%, respectively. The presence of P.indica caused a significant reduction in the shoot As concentration. With increasing shoot Fe concentration the shoot As concentration was decreased. The highest TPHS degradation was observed in non As-polluted soil that containing 1% (W/W) nano Fe-oxide in the presence of P.indica, while the lowest that was in As polluted soil (24 mg As/kg soil) without applying nano Fe-oxide and in the absence of P.indica. CONCLUSION: Increasing soil sorption properties due to nano Fe-oxide application had significant effect on TPHS degradation in the presence of P.indica. However the role of soil condition on the amount of TPHS degradation cannot be ignored.