Effects of exogenous proline on the physiological characteristics of Triticum aestivum L. and Lens culinaris Medik. under drought stress | Učinki dodajanja prolina na fiziološke lastnosti krušne pšenice (Triticum aestivum L.) in navadne leče( Lens culinaris Medik.) v razmerah sušnega stresa

English. Proline, which is an indicator of stress, is often considered as a good parameter for the testing of plants with good drought tolerance capacity. Thus, exogenous application of proline is a possible technique to avoid the deleterious effects of the drought on plant growth. The objectives of this study are to investigate the impact exogenous proline on the physiological behavior of two plant species, bread wheat, a monocot, and lentil, a dicot, under drought stress conditions. After several preliminary tests, optimal concentrations of exogenous proline were determined (6 mM for bread wheat and 2 mM for lentil) and both species were treated in normal and drought conditions. The results showed that water deficit affected both species leading to a reduction in growth, chlorophyll content and relative water content. Likewise, 15 % PEG-6000, which is equivalent to osmotic potential of -0.31MPa, caused a high accumulation of proline. In almost of cases we also noted a remarkable decrease in catalase (Cat), ascorbate peroxidase (APX) and gaiacol peroxidase (GPX) activities which was probably due to the oxidative stress caused by drought stress. The application of proline in stressful conditions reduced the deleterious effects caused by the stress on both species, due, particularly, to the accumulation of free endogenous proline and the increase of Cat, APX and GPX activities.

Slovenian. Proline je kot indikator stresa pogosto uporabljen za testiranje odpornosti rastlin na sušo. Z dodajanjem prolina se je mogoče izogniti škodljivim učinkom suše na rast rastlin. Predmet te raziskave je bil preučiti vpliv dodajanja prolina v rastni medij na fiziologijo dveh rastlinskih vrst, krušne pšenice kot enokaličnice in navadne leče kot dvokaličnice, gojenih v razmerah sušnega stresa. Po predhodnih poskusih sta bili določeni optimalni koncentraciji prolina, 6 mM za krušno pšenico in 2 mM za navadno lečo. Obe vrsti sta bili obravnavani s prolinom v normalnih in v sušnih razmerah. Rezultati so pokazali, da je pomanjkanje vode prizadelo obe vrsti, kar je vodilo v zmanšano rast, manjšo vsebnost klorofila in zmanjšano relativno vsebnost vode. Podobno je obravnavanje s 15 % PEG-6000, kar je enakovredno osmotskemu potencialu -0.31MPa, povzročilo veliko kopičenje prolina v obeh vrstah. Opažen je bil tudi znaten upad v aktivnosti katalaze (Cat) in askorbat perkosidaze (APX), kar je bilo verjetno posledica oksidacijskega stresa, povzročenega s sušo. Uporaba prolina je pri obeh vrstah zmanjšala škodljive učinke sušnega stresa z akumulacijo endogenega prolina, kar je tudi zmanšalo aktivnosti Cat, APX in GPX.