engleski

Proline research at the University of J. J. Strossmayer in Osijek, Croatia

The role of proline in plants exposed to stressful environmental conditions started three years ago at the University of Josip Juraj Strossmayer in Osijek (Croatia), in the collaboration with the University of the West of England (Great Britain). Some of the results obtained so far are presented here. The exposure of radish to the heavy metals stress in pots filled with soils having different metal contents, as well as the short exposure to 0.5 µM copper or lead in a nutrient solution (two days) in growth chamber conditions, resulted with high lipid peroxidation and proline accumulation, altered protein content and antioxidative enzymes activities. In the same experimental conditions, free proline accumulation and peroxidase activity in lettuce leaves under influence of copper stress imply possible interactions of different antioxidative pathways in lettuce. Free proline content was higher in soybean seedlings developed in optimal conditions of standard germination test as compared to chilling conditions of cold stress test. It seemed that proline accumulation in cotyledons was less promoted in seeds having low cold test and high electrical conductivity values, characterizing seeds with lower vigour. Exogenously applied proline to maize seed did not improve seed germination rate in cold stress conditions, however, such seed finally showed higher seedling fresh weight in comparison with untreated seed. In the investigation of cultivar, substrate type and light regime influence on proline accumulation in glasshouse grown gerbera plants, leaf proline content was not influenced by light regime. There was significant negative relation of chlorophyll b and proline content in leaves, whereas plants with lower leaf proline level had longer flower stalks. The observed synergistic relation of potassium to proline content in maize leaves was considered as the reaction of plant to multiple environmental stresses (heat, drought, low soil pH). Leaf proline was significantly related to grain % in ear fresh mass, accordingly, proline level in maize leaf could be considered as stress indicator in given experimental conditions. Future research shall be related to the evaluation of extreme temperature stress, salt stress and nutrient disturbances, as well as detrimental effects of heavy metals and lipid peroxidation products in plants, at different impact level, from molecular events in isolated cells up to the crop productivity level.

drought ; cold stress ; heavy metal stress ; heat stress ; salt stress

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