Effect of nicosulfuron and mesotrione herbicides and foliar fertilizer on the phytochemicals content in the sweet maize leaf and grain

Predmet ove disertacije bio je proučavanje uticaja herbicida sa ili bez primene folijarnog đubriva na sadržaj fitohemikalija u listu i zrnu četiri hibrida kukuruza šećerca (ZP504su, ZP355su, ZP553su i ZP515su) tokom dve godine, u cilju definisanja njihove tolerantnosti i karakterističnog odgovora. Sadržaj fitohemikalija određen je primenom visoko-efikasne tečne hromatografije sa ultravioletnim detektorom sa više dioda i fluorescentnim detektorom i visoko-efikasne jonske hromatografije sa pulsno-amperometrijskim detektorom. Sadržaj ukupnih fenolnih jedinjenja, glutationa i antioksidativna aktivnost određeni su primenom UV/VIS spektrofotometrije. Hromatografska razdvajanja su postignuta pri nižim protocima mobilnih faza uz smanjen utrošak organskih rastvarača podržavajući na taj način trendove zelene analitičke hemije. Dobra linearnost, tačnost, niska granica detekcije, direktno HPLC određivanje ekstrakata bez derivatizacije, skraćeno vreme ekstrakcije i trajanja analize omogućili su rutinsko korišćenje primenjenih hromatografskih metoda. Rezultati su pokazali da je uticaj tretmana bio izraženiji u zrnu, dok u listu uglavnom nije bio statistički značajan. Primena oba herbicida dovela je do statistički značajnog povećanja ukupnog sadržaja svih fitohemikalija u ZP553su na osnovu čega se on može definisati kao tolerantan genotip. Primenjeni tretmani izazvali su aktiviranje neenzimskih antioksidanasa kod ZP355su, a kod ZP515su aktiviranje metabolizma ugljenih hidrata. Rezultati su pokazali da se sadržaj karotenoida, vitamina E, fenolnih kiselina i šećera može koristiti kao jedinstven pokazatelj genotipa nakon primenjenih tretmana. Pokazano je da kontrolisana upotreba herbicida može dovesti do poboljšanja fitohemijskog profila i povećanja nutritivnog statusa kukuruza šećerca.The subject of this doctoral dissertation was the impact of herbicides with or without foliar fertilizer on phytochemicals content in leaf and grain in four hybrids of sweet maize (ZP504su, ZP355su, ZP553su, and ZP515su) during two years in order to define their tolerance and characteristic response. The content of phytochemicals was determined using high-performance liquid chromatography with an ultraviolet multi-diode detector and a fluorescent detector, and high-performance anion exchange chromatography with pulsed amperometric detection. The content of total phenolic compounds, glutathione and antioxidant activity was determined using UV / VIS spectrophotometry. Chromatographic separations were achieved at lower mobile phase flows with reduced consumption of organic solvents, thus supporting the trends of green analytical chemistry. Good linearity, accuracy, low limit of detection, direct HPLC determination of extracts without derivatization, shortened extraction time, and duration of analysis enabled the routine use of applied chromatographic methods. The results showed that the impact of the treatment was more conspicuous in the grain, while in the leaf it was generally not statistically significant. The application of both herbicides led to a statistically significant increase in the total content of all phytochemicals in ZP553su, based on which it can be defined as a tolerant genotype. The applied treatments caused the activation of non-enzymatic antioxidants in ZP355su, and in ZP515su the activation of carbohydrate metabolism. The results of this study indicated that the content of carotenoids, vitamin E, phenolic acids and sugars can be used as a characteristic phytochemical parameter of the genotype after the applied treatments. It has been shown that the controlled use of herbicides can lead to an improvement in the phytochemical profile and an increase in the nutritional status of sweet maize