Growth and antioxidant system responses of maize (Zea mays L.) seedling to different concentration of pyrene in a controlled environment | Rastni in antioksidacijski odziv sejank koruze (Zea mays L.) na različne koncentracije pirena v nadzorovanih razmerah

anglais. Polycyclic aromatic hydrocarbons (PAHs) are a class of organic pollutants effecting different aspects of plants physiology. To assess the physiological responses of plants to PAHs, maize (Zea mays) was treated with 25, 50, 75, and 100 ppm of pyrene and after 21 days, the activity of some antioxidant enzymes, malondialdehyde (MDA), total flavonoid, total anthocyanin, and soluble sugar contents were measured in shoots and roots of plants. Pyrene led to increase MDA content as well as CAT, POD, and SOD activities. Increase in pyrene concentration reduced all studied growth variables and significantly increased photosynthetic pigments contents of plants. Soluble sugar content was significantly higher in the shoot, while that was reduced in the roots through increasing of pyrene concentration (p < 0.05). Also, the increase of pyrene concentration decreased total flavonoid content compared to anthocyanin content. In conclusion, these findings supported the hypothesis that pyrene toxicity induces oxidative stress in the maize plant and it also increases the antioxidant systems in order to moderating stress condition. However, the antioxidant system of maize was not strong enough to eliminate all produced ROS at high concentrations, thus this caused oxidative damage to the plant and decreased its growth variables.

slovène. Policiklični aromatski ogljikovodiki (PAHs) so organska onesnažila, ki vplivajo na različne fiziološke procese v rastlinah. Za ovrednotenje fiziološkega odziva koruze na PAH-e so bile njene sejanke tretirane s 25, 50, 75, in 100 ppm pirena, po 21 dneh so bile izmerjene v koreninah in poganjkih aktivnost nekaterih antioksidacijskih encimov, vsebnost malondialdehida (MDA), celokupnih flavonoidov, antocianinov in topnih sladkorjev. Piren je povečal vsebnost MDA kot tudi aktivnosti CAT, POD in SOD. Povečanje koncentracije pirena je zmanjšalo vse merjene rastne parametre in povečalo vsebnost fotosinteznih barvil v rastlinah. Vsebnost topnih sladkorjev je bila s povečanjem koncentracije pirena značilno večja v poganjkih in manjša v koreninah (p < 0.05). Povečanje koncentracije pirena je zmanjšalo vsebnost celokupnih flavonoidov v primerjavi z antocianini. Zaključimo lahko, da toksičnost pirena inducira v rastlinah koruze oksidacijski stres in poveča odziv antioksidacijskega sistema na stresne razmere. Kljub temu odziv antioksidacijskega sistema koruze ni zadoščal za preprečitev tvorbe reaktivnih zvrsti kisika v večjih koncentracijah, kar je povzročilo oksidativne poškodbe v rastlinah in zmanšalo njihovo rast.