## 4 Discussion
### Plant and Enzyme Response to Petrochemical Products
In our studies on the bioindication of soil pollution by DO and G, we used enzymes of the oxidoreductase and hydrolase classes. Enzymes of the first class are considered primary bioindicators, while those of the second class are considered auxiliary [35]. We found that these enzymes were significantly positively correlated with SOM and CEC of the soil, as well as with the type and degree of contamination by DO and G. We observed a stimulation of oxidoreductase activity and most hydrolase enzymes by DO, while an inhibition of the investigated oxidoreductase and hydrolases by G was noted. Differences in enzyme response to contamination by both petroleum-derived products are likely to be due to thenature of the hydrocarbons they contain. Some microorganisms use these hydrocarbons as a source of carbon and energy [29; 34; 105], leading to increased proliferation [106] and expansion of the enzyme pool [107]. However, certain fractions of petroleum-derived products may contaminate microbial cells, perforate their cell membrane, and thus exert a toxic effect on them. Moreover, they may limit enzyme production and reduce substrate availability for enzymes [34]. The increased Corg content in the soil and consequently higher C content in microbial biomass result in enhanced enzyme activity, which explains the intensified enzyme activity in soil contaminated with DO. Generally, diesel oil is considered less harmful than gasoline. The Role of Dolomite and Perlite in Mitigating the Effect of Petroleum-Derived Products on Plants and Enzyme Activity  
Considering the fact that soil contamination with petroleum and its products poses a significant threat to the environment [9; 47; 102], often leading to the formation of \"technological deserts\" [98], there is an urgent need to improve methods for cleaning up areas affected by these products [98; 108; 109]. One such method is to combine phytoremediation with the simultaneous application of soil adsorbents to support bioremediation processes [110]. In our own research, dolomite and perlite were used to assist _Zea mays_ in detoxifying soils contaminated with DO and G. Dolomite is a carbonate adsorbent, while perlite is a silica-based adsorbent [54; 56; 59]. Both adsorbents possess properties such as sorption capacity and buffering capacity. They regulate soil water-air properties [110], and dolomite can additionally improve sorption capacity and restore soil morphology and physical and chemical properties disrupted by petrochemical contamination, mainly through processes such as sorption, precipitation, and dissolution. Sorption relies on two mechanisms. The first is determined by capillary phenomena leading to the filling of both pores and capillaries of appropriate diameter and surface energy [111]. One parameter of perlite that favors capillary formation is its low bulk density, not greater than 0.25 kg dm\({}^{-3}\)[62]. The second mechanism is sorption, which leads not only to the formation of a uniform oil layer around the grains but also to clusters of irregular structure. It is determined by both the morphology of the sorbent surface, including the presence of hydroxyl groups, and the molecular weight of the petrochemicals [59; 111]. The formation of stable macroaggregates with dolomite is the result of H\({}^{+}\) neutralization and suppression of H\({}^{+}\) dispersion and K\({}^{+}\) and Na\({}^{+}\) cations in the soil. Macroaggregates are formed by two types of bridges: Ca\({}^{2+}\) and Mg\({}^{2+}\) binding and salt bridges (CaCO\({}_{3}\), MgCO\({}_{3}\)). Al\({}_{2}\)O\({}_{3}\), Fe\({}_{2}\)O\({}_{3}\), and SiO\({}_{2}\) also play an important role in this process [112]. This explains the preferential adsorption of higher molecular weight petroleum products [113]. These factors indicate that in our studies both sorbents mitigated but did not completely eliminate the negative effects of the tested petrochemical products on the growth and development of maize. This is confirmed by the plant impact indices for dolomite and perlite.