Biochemical aspects of resistence of poplar (Populus spp) clones on water streess

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

Effect of drought stress on antioxidant status of wheat seedlings

The aim of this experiment was to study antioxidant status of two wheat varieties under drought stress. Investigated parameters were: relative water content (RWC), lipid peroxidation, proline content, and activity of antioxidant enzymes (SOD, CAT, and POD). The plants were grown for 3 weeks before drought was imposed by completed withheld of watering for 6 days. The results showed that ability of some wheat varieties to enhance enzymatic antioxidant activities might be an important attribute linked to drought tolerance. This could limit cellular damage caused by active oxygen species during water deficit

Assessment of drought stress on barley (Hordeum vulgare L.) seedlings using biochemical parameters

On a global scale, drought stress causes a significant threat to plant production. If barley plants experience drought stress at the seedling stage it may reduce plant fitness and affects the grain yield at the final stage of growth. In this study was investigated the relationship between drought and oxidative stress tolerance in barley. Twenty days after germination, two two-row winter barley cultivars NONIUS and NS 565 were exposed to 5 days long drought. The activity of antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT) and guaiacol peroxidise (POD) were determined. Lipid peroxidation and relative electrolyte leakage were investigated as parameters of oxidative stress. When NONIUS seedlings were exposed to drought stress, the antioxidant system could not effectively remove reactive oxygen species, leading to increased lipid peroxidation (an increase from 44.3 to 74.0 nmol/g FW) and damage of membrane (an increase from 8.9 to 23.9%). Drought stress also decreased relative water content (RWC) more in cultivar NONIUS than in cultivar NS 565, and increased proline content, soluble protein, and electrolyte leakage in both cultivar. Proline is effective in increasing the cell turgor and the activity of antioxidant enzymes. When plants were in drought conditions, proline accumulates in both cultivars more than in control

Effect of inoculation with PGPR on basil antioxidant activity

Basil (Ocimum basilicum L.) is a widely utilized culinary herb. It is used to flavour foods such as vegetables, meats, fish, etc. In traditional medicine is used for treatment of various disorders such as colds, respiratory diseases, cardiovascular diseases, metabolic and gastrointestinal disorders, etc. The effects of climate changes on agriculture can result in lower yield and nutritional quality of plants. The inoculation of plants with plant growth-promoting rhizobacteria (PGPR) such as Azotobacter, Streptomyces, and Bacillus are well known to lead to improvement in germination, growth, and yield. Also, it was found that PGPR enhance defence capacity of the plant. In this study, the basil seed were inoculated with selected PGPR isolates: Bac3, Azb, and Act. Control seeds were immersed into distilled water. After 6 weeks plant material was collected, and methanol extracts were prepared for antioxidant determinations. The changes in total phenol and flavonoid content, as well as antioxidant activity, were monitored. PGPR applied in the experiment have not cause significant changes in total phenol content. However, treatments with Azb and Act isolates have increased flavonoid content in basil plants. The antioxidant activity of basil plant has been measured as the ability of plant extracts to reduce DPPH radicals. Obtained results show that only treatment with Azb isolates significantly increases the antioxidant activity of basil plants. Results obtained in this study suggested that investigated isolates have different effects on the antioxidant characteristics of the basil plant. Further investigation is still needed to explore the possibility of using these PGPRs as potent bio-fertilizer in basil production

Antioxidative response of poplar tissue culture exposed to peg 6000

The aim of this work was to investigate the influence of the water deficit in poplar tissue culture (M-1 genotype) through proline content, level of lipid peroxidation and activities of antioxidative enzymes. Plants were exposed to PEG 6000 (100 and 200 mOsm) in in vitro conditions for 6 days. Malondialdehyde (MDA) content showed an increase only at 200 mOsm stress. Under the 100 mOsm stress, catalase and guaiacol peroxidase activities were induces indicating their important role in elimination of reactive oxygen species (ROS). Under the 200 mOsm stress, superoxide dismutase and guaiacol peroxidase activities were induced

Phytochemical characteristics and antioxidant capacity of fruit extracts of different prunus species

Fruits are one of the major sources of polyphenol compounds in human diet. These compounds are known to have many health-promoting activities, especially anticancer, antiradical and antioxidant effects. In this work, seven different Prunus species traditionally grown in south Bačka region of Vojvodina were investigated: blackthorn (P. spinosa), plum (P. domestica), apricot (P. armeniaca), cherry plum (P. cerasifera), sweet cherry (P. avium), sour cherry (P. cerasus) and mahaleb cherry (P. mahaleb). Freeze-dried fruits were evaluated in terms of their phytochemical characteristics and bioactivity, determining total content of phenolics, flavonoids and anthocyanins, total antioxidant capacity and antiproliferative effect on human colon cancer cells (HT29). Blackthorn fruits are the richest in phenolic and flavonoid contents, while mahaleb cherry and sweet cherry had much higher content of total anthocyanins than other examined species. Apricot and cherry plum fruits had the lowest levels of polyphenol compounds, but very high antiproliferative effect, almost the same as blackthorn. This indicates that not only polyphenol compounds contribute to antiproliferative effects. Concerning total antioxidant activity, blackthorn, sweet cherry, sour cherry and mahaleb cherry showed the highest capacity of scavenging DPPH radical and ferric reducing activity power

Comparison between Organic and Conventional Spelt and Wheatgrass juice

This work is aimed to compare antioxidant and scavenger properties of conventionally and organically produced speltgrass. Moreover, the antioxidant status of spelt was compared with wheatgrass. Three spelt varieties were analyzed:Nirvana, Ebners–Rotkorn variety and Eco-10. Antioxidant enzymes, superoxide-dismutase and guiacol-peroxidase, were determined as well as ferric reducing antioxidant power and DPPH-antiradical power. Total soluble proteins and total phenols were determined and also lipid peroxidation as a parameter of oxidative stress. The organically produced spelt was exposed to the higher levels of oxidative stress than conventionally produced spelt, and also DPPH antiradical power was induced by conventional production, which is also demonstrated using the relative antioxidant capacity index. The best antioxidant properties, better than wheat, showed organically produced spelt genotype Ebners–Rotkorn which is determined by the highest phenol content, superoxide-dismutase activity, DPPH antiradical power and ferric reduced antioxidant power and consequently with the lowest lipid peroxidation intensity

Biochemical aspects of resistence of poplar (Populus spp) clones on water streess

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