Unfavourable growth conditions significantly determine the yield of crop plants. Intraspecific competition is a condition in which plants compete with each other for environmental resources. An excessive density contributes to increased competition within species, which results in disruption of photosynthesis process. According to this idea, experiments were conducted to investigate the photosynthetic response of potato (Solanum tuberosum) plants to excessive congestion. Two potato varieties of different earliness classes (Vineta and Satina) were used to evaluate the efficiency of the photosynthetic apparatus based on chlorophyll (Chl) fluorescence measurements under stress conditions. Changes in Chl contents of the tested plants were also analysed. In relation to intraspecific competition, we can conclude that the Vineta variety was less sensitive to this stress factor. In contrast, the photosynthetic apparatus of the Satina variety showed less efficient functioning under these conditions. In this study, the application of Chl fluorescence was presented for the first time in order to analyse the effects of intraspecific competition in plants., J. Olechowicz, C. Chomontowski, P. Olechowicz, S. Pietkiewicz, A. Jajoo, M. H. Kalaji., and Obsahuje bibliografii
The aim of this work was to determine two types of photosynthetic water-use efficiency in order to examine their utility as selection criteria for tolerance of energy crops to soil water deficit. Furthermore, effects of crop cultivation on soil water content and storage were investigated. Seven energy crops were examined: miscanthus, prairie cordgrass, willow, thorn-free rose, Virginia mallow, Bohemian knotweed, and topinambour. The highest values of instantaneous (WUE) and intrinsic (WUEi) water-use efficiencies were found for miscanthus and prairie cordgrass. The reduction of WUE and/or WUEi was caused mainly by a rapid rise in the transpiration rate and a greater stomatal conductance, respectively. Principal component analysis showed that neither WUE nor WUEi could be recommended as universal selection criteria for the drought tolerance in different energy crops. The proper localization of soil with a good supply of water is most the important condition for energy crop plantations., S. Podlaski, S. Pietkiewicz, D. Chołuj, T. Horaczek, G. Wiśniewski, D. Gozdowski, H. M. Kalaji., and Obsahuje bibliografii