Uticaj abiotičkog i biotičkog stresa na promenu fitohemikalija u listu i zrnu kukuruza - posledice po kvalitet i bezbednost hrane

Abstract

Upotreba kukuruza u ishrani ljudi i životinja ima široku primenu jer predstavlja izvor različitih tohemikalija koje povoljno utiču na metaboličke procese. Tokom vegetacije biljka kukuruza izložena je različitim uticajima abiotičkog i biotičkog stresa. Napad jedne od najznačajnijih štetočina kukuruza, larve Ostrinia nubilalis zavisi od uslova sredine i može dovesti do smenjenja prinosa i do 30%. Oštećenja nadzemnih delova biljke povećavaju rizik od pojave truleži klipa, jer predstavljaju mesta

sekundarne infekcije izazvane različitim patogenim gljivama. Jedna od neophodnih agrotehničkih mera je primena pesticida u poljoprivredi u cilju suzbijanju kako štetočina tako i korova, obezbeđujući stabilan prinosa. S druge strane, primena pesticida, nepovoljni uslovi spoljašnje sredine i biotički stres mogu dovesti do oksidativnog stresa, oštećenja ćelija i pojave slobodnih radikala i reaktivnih vrsta kiseonika (engl. reactive oxygen species - ROS). Ćelije i tkiva biljaka

imaju razvijene antioksidativne sisteme odbrane koji ihibiraju ili vezuju slobodne

radikale.

Najznačajniji neenzimski antioksidansi su avonoidi, fenolne kiseline, karotenoidi, tokoferoli, tinska kiselina, vitamin C, i glutation. Osim promena u prinosu i antioksidativnom statusu, kod biljke može doći i do promena u količini i drugih tohemikalija kao što su proteini, šećeri, amnokiseline i masne kiseline. Do sada su nedovljno ispitani uticaji pesticida i abiotički stres koji mogu da izazovu promene na različitim tkivima kukuruza, pri čemu je više pažnje posvećano

promeni tohemikalija

izazvanoj uticajem spoljašnje sredine kao što je vodni decit. U cilju pronalaženja karakterističnog odgovora genotipa, u odnosu na promene tohemijskog sadržaja, kao i eventualno izdvajanje genotipa tolerantnog na potencijalni stres primenjuju su metode spekrofotometrije i savremene metode tečne i gasne hromatograje za odredjivanje tohemikalija u biljci.

The use of maize in human nutrition and livestock feed is widely used because it is a source of various phytochemicals that have a positive efect on metabolic processes. During the growing season, the maize plant is exposed to various influences

of abiotic and biotic stress. Ostrinia nubilalis larvae, one of the predominant maize

pests, can reduce plant growth and cause stalk and ear damage, leading to a yield

decrease of up to 30%. Damage to the above-ground parts of the plant increases

the risk of cob rot, presenting sites of secondary infection caused by pathogenic

fungi. One of the necessary agrotechnical strategies is the application of pesticides

in order

to control both pest and weed impact, providing stability of yield. On the other hand, the application of pesticides, negative environmental impacts, and biotic stress can lead to oxidative stress, cell damage and the appearance of free radicals and reactive oxygen species (ROS). Cells and plant tissues have developed antioxidant defense systems that inhibit or bind free radicals. The most

important non-enzymatic antioxidants are flavonoids, phenolic acids, carotenoids,

tocopherols,

phytic acid, vitamin C, and glutathione. In addition to changes in yield and antioxidant status, alteration of other phytochemicals such as proteins, sugars, amino acids and fatty acids can also occur in the plant. The effects of pesticides and abiotic stress that they can cause on different tissues of

maize have been insufficiently investigated. More attention has been given to the changes in phytochemicals content caused by the influence of the environment such as water deficit. In order to find the response of the genotype, in relation to changes in the phytochemical content, as well as the eventual selection of a genotype tolerant to potential stress, spectrophotometry methods and modern methods of liquid and gas chromatography were applied to determine phytochemicals in the plant.