Martin Koudela

Comparing the removal of polycyclic aromatic hydrocarbons in soil after different bioremediation approaches in relation to the extracellular enzyme activities

A 120-day experiment was conducted to compare the removal of polycyclic aromatic hydrocarbons (PAHs) from agricultural soil after natural attenuation (NA), phytoremediation (P), mycoremediation (M), and plant-assisted mycoremediation (PAM) approaches in relation to the extracellular enzyme activities in soil. The NA treatment removed the total soil PAH content negligibly. The P treatment using maize (Zea mays) enhanced only the removal of low and medium molecular PAHs. The Pleurotus ostreatus cultivated on 30-50 mm wood chip substrate used in M treatment was the most successful in the removal of majority PAHs. Therefore, significantly (p < 0.05) highest total PAH removal by 541.4 μg/kg dw (dry weight) (36%) from all tested M treatments was observed. When using the same fungal substrate together with maize in PAM treatment, the total PAH removal was not statistically different from the previous M treatment. However, the maize-assisted mycoremediation treatment significantly boosted fungal biomass, microbial and manganese peroxidase activity in soil which strongly correlated with the removal of total PAHs. The higher PAH removal in that PAM treatment could be reflected in the following post-harvest time. Our suggested M and PAM approaches could be promising in situ bioremediation strategies for PAH-contaminated soils.

COMPARISON OF THE CARBOHYDRATE CONTENT IN APPLES AND CARROTS GROWN IN ORGANIC AND INTEGRATED FARMING SYSTEMS

The aim of this study was to compare some quality parameters of apples and carrots from organic and integrated farming systems. In addition, the cultivars of carrots were grown in two plant densities (600 or 900 thousand plants per hectare). The fructose, glucose, saccharose and dry matter content of seven apple cultivars (Florina, Zvonkove, Topaz, Sampion, Ontario, Melrose and Idared) and two carrot cultivars (Afalon F1 and Cortina F1) were analysed by HPLC and gravimetric methods, respectively. Significant differences were found between organic and integrated apple samples. The interactions between cultivars and farming methods were also significant (p <0.0001). The dry matter and sugar level tendencies were not the same for all apple cultivars. Conversely, more consistent data were obtained for the two carrot cultivars. The bio carrots of both cultivars showed significantly lower dry matter content (p = 0.0004) and higher carbohydrate content (pfructose = 0.0303, pglucose = 0.0003, psucrose = 0.0083) than the samples from integrated production. Other factors like cultivar and plant density also played an important role in sugar content in carrots. Different densities of plants significantly affected the glucose content (p = 0.0373). Cultivar Aftalon F1 showed higher concentration of monosaccharides compared to Cortina F1 (pfructose = 0.0001 and pglucose <0.0001).