RAZINE LIPIDNE PEROKSIDACIJE U DIJELOVIMA SJEMENA SOJE (Glycine max (L.) Merr.) KAO POSLJEDICA STRESA PRI USVAJANJU VODE

High rainfall and rapid water uptake by dry seed after sowing in the field can result in so-called seed imbibitional damage. Here, lipid peroxidation levels were evaluated in seed testa, embryos and cotyledons of three soybean cultivars (Podravka 95, Tisa and Vita), after 3, 6, 12 and 24 h of seed imbibition in water at 20oC. In general, lipid peroxidation was enhanced in soybean embryos and the lowest vales were observed in seed testa. With respect to imbibition duration, the highest lipid peroxidation was observed after 3 h of imbibition and decreased thereafter in seed of Podravka 95 and Vita, with similar trend regarding seed of the same age.Intenzivne oborine i intenzivno usvajanje vode suhoga sjemena nakon sjetve u polju mogu rezultirati takozvanim imbibicijskim oštećenjem sjemena. U ovom istraživanju analiziran je intenzitet lipidne peroksidacije u sjemenjači, klici i kotiledonima sjemena tri sorte soje (Podravka 95, Tisa i Vita), nakon 3, 6, 12 i 24 imbibicije u vodi pri 20oC. U cjelini, lipidna peroksidacija bila je povećana u klici soje, a najslabije izražena u sjemenjači. S obzirom na dužinu imbibicije, najveći intenzitet lipidne peroksidacije utvrđen je nakon 3 h imbibicije, nakon čega se smanjivao kod sorata Podravka 95 i Vita, uz sličan trend, s obzirom na sjeme iste starosti

INFLUENCE OF TEMPERATURE ON LETTUCE (Lactuca sativa L.) AND CARROT (Dancus carota L.) SEED GERMINATION AND EMERGENCE

Od abiotskih čimbenika koji utječu na klijavost sjemena, jedna od najvažnijih je toplina. Visoka ili niska temperatura zraka mogu značajno smanjiti klijavost sjemena većine poljoprivrednih kultura. Cilj ovog istraživanja je bio utvrditi utjecaj temperature zraka na klijavost i nicanje deklariranog sjemena salate i mrkve. Klijavost i nicanje sjemena obje kulture ispitana je u uvjetima optimalne (20°C) i povišene temperature (30°C) u kontroliranim uvjetima te niskih temperatura zraka tijekom ranih rokova sjetve na otvorenom. Značajno smanjenje klijavosti primijećeno je na povišenoj temperaturi kod mrkve (16%), dok je nicanje bilo značajno manje kod obje kulture u uvjetima niskih temperatura tijekom poljskih pokusa, i to do 41% kod mrkve i do 57% kod salate u usporedbi sa laboratorijskom klijavošću. Iz rezultata ovog istraživanja, može se zaključiti da je stres zbog niskih temperatura značajno utjecao na smanjenje sklopa kod obje kulture u vrijeme sjetve i nicanja.Among different abiotic factors that influence seed germination, one of the most important is warmth. Either high or low temperature can significantly decrease seed germination of different agricultural crops. The aim of this investigation was to determine the influence of temperature and sowing time on germination of declared lettuce and carrot seeds. Seed germination and emergence of both crops was tested in conditions of optimal (20°C) and high temperature (30°C) in controlled environment and low temperature during early sowing periods in open field. Carrot seed germination significantly decreased (16%) in high temperature conditions. Moreover, emergence percentage significantly decreased in both species during field trials by about 41% for carrot and up to 57% for lettuce compared to laboratory germination. It can be concluded that stress caused by low temperatures during sowing time and emergence significantly decreases emergence percentage that resulting in low plant density

INFLUENCE OF TEMPERATURE ON LETTUCE (Lactuca sativa L.) AND CARROT (Dancus carota L.) SEED GERMINATION AND EMERGENCE

Od abiotskih čimbenika koji utječu na klijavost sjemena, jedna od najvažnijih je toplina. Visoka ili niska temperatura zraka mogu značajno smanjiti klijavost sjemena većine poljoprivrednih kultura. Cilj ovog istraživanja je bio utvrditi utjecaj temperature zraka na klijavost i nicanje deklariranog sjemena salate i mrkve. Klijavost i nicanje sjemena obje kulture ispitana je u uvjetima optimalne (20°C) i povišene temperature (30°C) u kontroliranim uvjetima te niskih temperatura zraka tijekom ranih rokova sjetve na otvorenom. Značajno smanjenje klijavosti primijećeno je na povišenoj temperaturi kod mrkve (16%), dok je nicanje bilo značajno manje kod obje kulture u uvjetima niskih temperatura tijekom poljskih pokusa, i to do 41% kod mrkve i do 57% kod salate u usporedbi sa laboratorijskom klijavošću. Iz rezultata ovog istraživanja, može se zaključiti da je stres zbog niskih temperatura značajno utjecao na smanjenje sklopa kod obje kulture u vrijeme sjetve i nicanja.Among different abiotic factors that influence seed germination, one of the most important is warmth. Either high or low temperature can significantly decrease seed germination of different agricultural crops. The aim of this investigation was to determine the influence of temperature and sowing time on germination of declared lettuce and carrot seeds. Seed germination and emergence of both crops was tested in conditions of optimal (20°C) and high temperature (30°C) in controlled environment and low temperature during early sowing periods in open field. Carrot seed germination significantly decreased (16%) in high temperature conditions. Moreover, emergence percentage significantly decreased in both species during field trials by about 41% for carrot and up to 57% for lettuce compared to laboratory germination. It can be concluded that stress caused by low temperatures during sowing time and emergence significantly decreases emergence percentage that resulting in low plant density

The effects of seed priming with sodium hydrosulphide on drought tolerance of sunflower (Helianthus annuus L.) in germination and early growth

© 2020 Association of Applied Biologists Sunflower seeds (hybrid Luka) were primed with water (hydropriming) or sodium hydrosulphide (NaHS) solutions (0.1, 0.5, 1.0 and 1.5 mM NaHS) and subsequently dried to initial moisture content. Unprimed (control) and primed seeds were germinated in a growth chamber on paper towels moistened with water or polyethylene glycol (PEG) 6000 solutions (2.5, 5.0 and 10%), mimicking different drought stress levels. To evaluate the response of the primed seeds to drought in the germination stage, the germination energy (GE), germination rate (SG), seedling fresh mass (SW), hydrogen peroxide and free proline content (PRO), as well as lipid peroxidation rate (malondialdehyde; MDA) were established. The results show strong effects of the imposed drought stress and the metabolic response to oxidative stress through lower germinability and proline accumulation in seedlings. NaHS priming showed some positive effects on seed germination depending on stress level and the concentration of NaHS. Sunflower seeds were also germinated in pots filled with soil, at optimal (70% of field water capacity [FWC 70%]) and drought conditions (FWC 30%), in natural outdoors conditions. When plantlets developed the first pair of leaves, the number of plants (emergence rate [ER]), shoot mass (SM) and leaves mass (LM) were determined, as well as the total activities of catalase (CAT), ascorbate peroxidase (APX), glutathione reductase (GR) and dehydroascorbate reductase (DHAR). There was a significant influence of an interaction between drought stress and priming, whereas drought stress inhibited plant emergence and early growth (SW and LW), and strong antioxidative enzymatic response to drought stress was clearly established in the leaves. Although seed priming showed some influence on enzyme activities, it was mostly related to seed hydropriming effects, while NaHS seed priming was less effective, influencing only DHAR. Altogether, the results imply that sunflower seed priming with NaHS may not have a prolonged impact on the antioxidative defence mechanism based on CAT and ascorbate/glutathione cycle during sunflower early growth in drought conditions

LIPID PEROXIDATION LEVELS IN SOYBEAN (Glycine max (L.) Merr.) SEED PARTS AS A CONSEQUENCE OF IMBIBITION STRESS

High rainfall and rapid water uptake by dry seed after sowing in the field can result in so-called seed imbibitional damage. Here, lipid peroxidation levels were evaluated in seed testa, embryos and cotyledons of three soybean cultivars (Podravka 95, Tisa and Vita), after 3, 6, 12 and 24 h of seed imbibition in water at 20oC. In general, lipid peroxidation was enhanced in soybean embryos and the lowest vales were observed in seed testa. With respect to imbibition duration, the highest lipid peroxidation was observed after 3 h of imbibition and decreased thereafter in seed of Podravka 95 and Vita, with similar trend regarding seed of the same age

The relationship of proline content and metabolism on the productivity of maize plants

The free proline content in maize ear-leaves, silk and pollen were analyzed in field grown plants which had matured to the pollination stage. Using maize hybrids PR34F02, PR35P12 and PR36B08 field trials were set up at two locations in eastern Croatia in two different years. Two enzymes of proline metabolism were analyzed in the same leaf samples and specific activities of synthetase (P5CS) and proline dehydrogenase (PDH). Plant productivity was evaluated at harvest by the estimation of total and fully developed grain number per ear and per plant, the mean single grain mass, and the mass of grain per plant. The year in which the plants were grown had a very significant effect on the free proline content in the leaf and pollen, as well as on the enzyme activities assayed. The differences between the plants from the two localities were very significant in all tested parameters of plant grain productivity. There was a significant genotype effect on proline content and P5CS total activity in leaf and on all the productivity parameters. Some of the correlations established suggest that the rate of proline synthesis and degradation in maize ear-leaf at pollination might contribute to the final grain production of the maize plant. Multiple regression analyses was used to further analyze the relationship between proline and grain productivity, but it is clear that future work should include other environmental conditions, plant species and organs such as roots