Morfofiziološke osobine paradajza u uslovima povećanog saliniteta

Abstract

Prilikom proizvodnje paradajza u zaštićenom prostoru često dolazi do pojave stresa usled povećane zaslanjenosti supstrata, što je posledica intenzivnog prihranjivanja, korišćenja neadekvatne vode za navodnjavanje i nemogućnosti prirodnog ispiranja zemljišta. Jedna od najpopularnijih metoda kojom se mogu prevazići problemi gajenja biljaka u ovakvim uslovima, a koja nema nikakvih štetnih posledica za okolinu, je kalemljenje. Stoga je cilj ovog rada bio da se ispita stepen morfoloških. biohemijskih i fizioloških promena koje nastaju kod dva hibrida paradajza (Buran F1 i Berberana F1), gajenih iz kalemljenog i nekalemljenog rasada, u prisustvu različitih koncentracija soli (NaCl) u podlozi (EC 1.7 dS m-1 (kontrola), 3.8 dS m-1 (S1), 6.9 dS m-1 (S2) i 9.1 dS m-1 (S3)). Dvanaest nedelja nakon sadnje, u fenofazi plodonošenja izmereni su intenzitet fotosinteze, transpiracije i protok gasova kroz stome. Uzorkovani su listovi i u njima je ispitana aktivnost antioksidantnih enzima (SOD, askorbat peroksidaza i klasa III peroksidaza). Izmerena je masa potpuno zrelih plodova sa prve plodonosne grane (uzorkovanih u isto vreme kada i listovi) i u njima su izmerene koncentracije likopena, askorbinske kiselina, fenolnih jedinjenja i ukupni antioksidacioni kapacitet. Različiti nivoi zaslanjenosti supstrata u ogledima doveli su do značajnih promena u rastu i metabolizmu ispitivanih hibrida paradajza. Ustanovljena je razlika u reakciji kalemljenih i nekalemljenih hibrida paradajza na S1, S2 i S3. SOD i askorbat (AA) su imali ključnu ulogu u antioksidativnoj zaštiti biljaka, dok je u dugoročnom odgovoru paradajza na S1, S2 i S3, tokom faze zrenja, uloga peroksidaza bila manje značajna. Konstatovana je interhibridna razlika u aktivnosti SOD i AA. Tokom dvanaest nedelja izloženosti biljaka paradajza sonom stresu biljke su se dobro adaptirale, na šta ukazuje povećan sadržaj AA, kao i odnos AA/DHA, što je verovatno posledica brze regeneracije AA. Takođe, kalemljene biljke su imale niži sadržaj neenzimskih antioksidativnih komponenti u listovima i plodovima kod oba ispitivana hibrida, na svim nivoima povećane zaslanjenosti supstrata. Prosečna masa plodova kalemljenih biljaka je, u zavisnosti od nivoa zaslanjenosti supstrata, bila za 40% do 60% veća u poređenju sa nekalemljenim, što je veoma važno sa tržišnu vrednost proizvodnje. Rezultati ove disertacije su omogućili da se sagleda i kvantifikuje uticaj kalemljenja na tolerantnost paradajza prema povećanoj koncentaciji soli u podlozi, što je veoma značajno za proizvodnju ove vrste povrća. Datum

Stress conditions often occur during the tomato production in greenhouses due to increased substrate salinity, which is the result of intensive fertilization, use of inadequate water for irrigation and impossibility of natural soil rinsing. One of the widely used methods by which the problems of plant cultivation under increased salinity can be overcome, and which has no harmful effects on the environment, is grafting. Therefore, the aim of this research was to examine the level of morphological, biochemical and physiological changes occurring in two tomato hybrids (Buran F1 and Berberana F1) grown from grafted and non-grafted seedlings in the presence of different salt concentrations (EC 1.7 dS m-1 (control), 3.8 dS m-1 (S1), 6.9 dS m-1 (S2) and 9.1 dS m-1 (S3)). Twelve weeks after planting, in fruiting phenophase, intensity of photosynthesis, transpiration and gas exchange through stomata were measured. Leaves were sampled and the activities of antioxidant enzymes (SOD, ascorbate peroxidase and class III peroxidase) in them was assessed. The weight of fully mature fruits from the first fruiting branch (sampled at the same time as the leaves) was measured and the concentrations of lycopene, ascorbic acid, phenolic compounds and total antioxidant capacity were measured in them. Different levels of substrate salinity in experiments led to significant changes in the growth and metabolism of the examined tomato hybrids. The difference in the reaction of grafted and non-grafted tomato hybrids to S1, S2 and S3 was found. SOD and ascorbate (AA) played a key role in the antioxidant protection, while in the long-term response of tomatoes to S1, S2 and S3, during the ripening phase, the role of peroxidases was less significant. Inter-hybrid differences in SOD and AA activity was also found. During the twelve weeks of exposure of tomato plants to salt treatments, the plants adapted well, as indicated by the increased AA content, as well as the AA/DHA ratio, which is probably the result of rapid AA regeneration. Moreover, the concentration of nonenzymatic antioxidant components in the leaves and fruits of both examined hybrids, was lower in grafted plants, at all levels of increased substrate salinity. The average weight of fruits of grafted plants, depending on the level of substrate salinity, was 40% to 60% higher compared to the non-grafted, which is very important for the market value of tomato production. The results of this dissertation have made it possible to perceive and quantify the effect of grafting on tomato tolerance towards the increased salt concentration in the substrate, which is very important for the successful production of this vegetable. Accepted