Biohemijski mehanizmi otpornosti klonova topole (Populus spp.) na vodni stres

Abstract

Cilj ove doktorske disertacije predstavljalo je ispitivanje uticaja vodnog stresa izazvanog sa polietilen glikolom (PEG) 6000 na biohemijske osobine klonova topole. Reznice tri klona topole (M-1, B-229 i PE19/66) su hidroponski gajene i izložene 100 mOsm i 200 mOsm PEG 6000 tokom šest dana. Nakon tretmana u kontrolnim i stresiranim biljkama su ispitane promene aktivnosti antioksidantnih enzima, aktivnost dva enzimska markera polifenolnog metabolizma, fenolni profil, antioksidantna aktivnost, kao i sadržaj prolina i glicin betaina (GB). Takođe, ispitan je biohemijski odgovor kulture tkiva klona M-1 na vodni stres izazvan sa PEG 6000. U oba eksperimenta uočeno je da je akumulacija prolina i GB u uslovima vodnog stresa izazvanog sa PEG 6000 najvažnija strategija u otpornosti na stres i prevazilaženju vodnog deficita, tako da se ovi parametri mogu definisati kao najbolji indikatori otpornosti topole na sušu. Rezultati ovog istraživanjaupotpunjavaju saznanja o povezanosti oksidativnog stresa uzrokovanog vodnim stresom sa antioksidantnim odgovorom, nivoom oštećenja lipida i proteina, uključivanjem osmolita kao i promenama u polifenolnom profilu. Takođe, dobijeni rezultati su značajni za odabir klonova topola tolerantnih na vodni stres i za pošumljavanje sušnih staništa, kojih će biti sve više usled negativnog uticaja klimatskih promena.

The aim of presented doctoral thesis was investigation of the impact of water deficit caused by polyethylene glycol (PEG) 6000 on biochemical features of poplar clones. During six days, cuttings of three poplar clones (M-1, B-229 and PE 19/66) were grown in hydroponics and subjected to 100 and 200 mOsm PEG 6000. Changes in the activity of antioxidant enzymes, polyphenol characterization, two enzymatic markers of polyphenol metabolism, antioxidant capacity, as well as proline and glycine betaine content were investigated in stressed plants. Furthermore, assessment of biochemical response of poplar clone M-1 tissue culture to water stress induced by PEG 6000 was performed. In both experiments, the most important strategy for stress resistance and overcoming water deficiency was accumulation of proline and glycine betaine so these parameters can be defined as the best indicators of poplar resistance to drought. The results of this study complete the findings on the oxidative stress caused by water stress and their relationship with the antioxidant response, the level of lipid andprotein damage, accumulation of the osmolites and changes in the polyphenol profile. Also, the obtained results may be important for the selection of poplar clones resistant to water stress and for afforestation in arid sites, which appeared to be more numerous due to the effects of global climate change.