The use of light-emitting diode (LED) technology for plant cultivation under controlled environmental conditions can result in significant reductions in energy consumption. However, there is still a lack of detailed information on the lighting conditions required for optimal growth of different plant species and the effects of light intensity and spectral composition on plant metabolism and nutritional quality. In the present study, wheat plants were grown under six regimens designed to compare the effects of LED and conventional fluorescent lights on growth and development, leaf photosynthesis, thiol and amino acid metabolism as well as grain yield and flour quality of wheat. Benefits of LED light sources over fluorescent lighting were manifested in both yield and quality of wheat. Elevated light intensities made possible with LEDs increased photosynthetic activity, the number of tillers, biomass and yield. At lower light intensities, blue, green and far-red light operated antagonistically during the stem elongation period. High photosynthetic activity was achieved when at least 50% of red light was applied during cultivation. A high proportion of blue light prolonged the juvenile phase, while the shortest flowering time was achieved when the blue to red ratio was around one. Blue and far-red light affected the glutathione- and proline-dependent redox environment in leaves. LEDs, especially in Blue, Pink and Red Low Light (RedLL) regimens improved flour quality by modifying starch and protein content, dough strength and extensibility as demonstrated by the ratios of high to low molecular weight glutenins, ratios of glutenins to gliadins and gluten spread values. These results clearly show that LEDs are efficient for experimental wheat cultivation, and make it possible to optimize the growth conditions and to manipulate metabolism, yield and quality through modification of light quality and quantity.

Abstract. A number of C 3 temperate dry grassland species and winter wheat plants were grown in open top chambers either at 365 µmol mol -1 (AC) or at 700 µmol mol -1 (EC) air CO 2 concentrations. Gas exchange measurements were made at several air CO 2 concentrations. When measured at higher CO 2 concentrations, net photosynthetic rate was higher in plants grown at EC than at AC. The widely accepted Farquhar net photosynthesis model was parameterized and tested using several observed data. After parameterization the test results corresponded satisfactorily with observed values under several environmental conditions.

Nowadays, studying the impact of climate change on agricultural crops is of great importance in national and international projects. Research on the effects of climate change on agricultural cultivars is supported by crop growth models. Simulations provide facilities for the low cost investigation of the effects of many factors, both independently of each other and in combination. These models require parameterisation and testing, which can be done using data measurements. In order to test the correctness of the simulations of meteorological and nutrient supply effects, it is necessary to use the results of long-term field experiments with many replicates.In the present study, the Ceres Wheat and AFRCWHEAT2 winter wheat crop growth models were tested, utilizing the data of a five-year sowing date experiment and the relevant meteorological data. An analysis was made of whether changes in the sowing date were able to influence or eliminate the negative effects of the changing climate. It was found that choosing the optimum sowing date could be the key to adapting to changing conditions.