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The pattern of electric signals accompanying compatible and incompatible pollination were studied in pistils of petunia (Petunia hybrida L.) and rape (Brassica napus L). Electric potential was recorded for 4–7 hours with non-polarizable Ag/AgCl electrodes implanted into the ovary and beneath the sigma. At the end of measurements, pistils were fixed and the growth of pollen tubes was analyzed under a fluorescent microscope. Action potentials appeared in both species. In rape the potential dropped by 10 mV for few minutes after pollination regardless of the compatibility of the cross. In this species, during compatible pollination action potentials with amplitudes of 15–20 mV were recorded up to one hour after pollination. They were followed by a long lasting decrease of the potential by 10 to 50 mV. Contrary, after the self-incompatible pollination, action potentials were rare and of lower amplitudes and the potential gradually raised in comparison to the initial level. During the first hour after the compatible pollination of Petunia hybrida series of action potentials with amplitudes reaching 10–20 mV were recorded. At the time corresponding to the pollen tubes entrance to the transmitting tissue of the style, action potentials reaching up to 40 mV were followed by a steady decrease of the potential. The electric signals traveled along the style with velocity of 25 mm/s. Incompatible pollination in petunia resulted only in minor oscillation and gradual increase of the potential up to 100 mV in comparison to the initial level. The present investigation demonstrated that each phase of pollen-stigma recognition events, germination and growth of pollen tubes within the style have its characteristic pattern of electric changes which was species specific and depended on compatibility of the cross.
The aim of this study was the evaluation of membrane permeability of callus cells of several Polish meadow fescue cultivars, which were treated with toxins of two leaf spot pathogens Bipolaris sorokiniana and Drechslera dictyoides. Fungus metabolites were obtained by the method described by Lepoivre et al. (1986). Calli of cultivars ‘Skrzeszowicka’, ‘Skawa’, ‘Westa’, POB 282, POB 383, KOA 186 have been selected on medium with metabolites for two weeks. Next the conductivity test of electrolyte leakage and of total ion contents in the examined tissue was done. On the base of this data the membrane permeability coefficients for each cultivar were calculated. Toxins of B. sorokiniana damaged the cell membranes more strongly than metabolites of D. dictyoides. The significant differences of several objects sensitivity to the influence of B. sorokiniana metabolites were stated. These differences were not observed in the case of the influence of D. dictyoides metabolites on the examined tissue.
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