INTERAKCJA POMIĘDZY INTENSYWNOŚCIĄ ŚWIATŁA A STRESEM SUSZY I ICH WPŁYW NA WZROST SIEWEK PSZENICY

Abstract

In this paper, wheat seedlings were exposed to different levels of photon flux density (PFD) and drought stress. Seedlings of the wheat cv. Goplana were cultivated in controlled conditions in a miniphytotrone and exposed to three different photosynthetic photon flux densities (400, 800, and 1200 μmol⋅m−2⋅s−1) and drought stress (a water potential of −0.6 MPa). The Hoagland’s solution-treat- ed seedlings served as a control. The fresh and dry matter of the overground parts and roots, rela- tive chlorophyll concentration, electrical conductivity and chlorophyll fluorescence parameters were measured. Drought stress decreased the biomass of wheat seedlings, cv. Goplana. Higher intensities of photosynthetically active irradiation stimulated biomass growth both under control conditions and under drought stress. Drought and higher PFD intensity resulted in a decrease in chlorophyll content. Only the highest light intensity, together with drought stress, negatively affected the structure of cell membranes, increasing their permeability. Both of the applied stress factors did not cause significant changes in the values of the determined parameters of chlorophyll fluorescence in the leaves of wheat seedlings. These results suggest that the increase in light intensity has a mobilising effect on the plant, stimulating the development of biomass both under control conditions and under drought stress. No changes in the values of chlorophyll fluorescence parameters under the influence of different light intensities and drought stress may indicate that there were no significant disturbances in the course of the light phase of photosynthesis in the leaves of the tested seedlings.