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Cucumber (Cucumis sativus L. cv. Dar) leaves exposed to UV-B irradiation at a biologically effective dose of 9.5 kJ m-2d-1 showed decreased chlorophyll fluorescence parameter values versus the control; in peppermint (Mentha piperita L. cv. Asia) leaves those values were almost unchanged after treatment. Fv/Fo and Rfd were reduced more than other values, indicating inhibition of the oxygen-evolving complex and cooperation between the light and dark photosynthesis reactions as the primary targets of UV-B. The photosynthetic electron transport rate showed less change directly after irradiation, but after 24 h of recovery it was reduced to 50% of the control. Generally, photosystem II of peppermint leaves appeared more tolerant to the applied UV-B radiation than in cucumber leaves.
The plants of bean (Phaseolus vulgaris L. cv. Aura) grown in controlled conditions (PAR 150 μmol‧m⁻²‧s⁻¹, air humidity 50%, temperature 22°C/18°C, day/night, photoperiod 12 h) were subjected to UV-B irradiation (UV-Bʙᴇ = 1.86 kJ‧m⁻²‧d⁻¹). Then, sample discs were cut out from the leaves and treated for two hours with chill (2°C) in high light (PAR 600 μmol‧m⁻²‧s⁻¹ ). The chilling induced a decrease in the measured chlorophyll fluorescence parameters, particularly in the UV-B irradiated plants, indicating disturbances of the primary photochemical reactions of photosynthesis. The greatest changes were observed in the Rfd parameter, determining co-operation between the light and dark enzymatic photosynthetic reactions.
The plants of oilseed rape (Brassica napus var. oleifera L. cv. Marita) grown in summer in the glasshouse at UV-B irradiation using lamps TL40/12 during 21 days at daily dose of biologically effective UV-BBE = 2.4 kJ·m⁻²·d⁻¹ ( + U) or without UV-B (-U). Sample discs were cut out from the leaves and placed on the atrazine solution (A) or on distilled water (0) where stayed for 3 hours in light. Chlorophyll fluorescence parameters were measured by means of Hansatech Plant Efficiency Analyser (FV/FO, Rfd) and PAM-200 (ETR, qP). Photosynthetic electron transport in the oilseed rape plants was inhibited alike by UV-B radiation and by atrazine used independent, and atrazine applied in the UV-B irradiated plants affected in similar extent. Obtained results indicate more targets of the UV-B radiation action in the photosystem II than atrazine as other triazine herbicide, which block photosynthetic electron flow only on reducing side of photosystem II.
The purpose of this paper is to estimate an oxidation state of plant oils by the chemiluminescence method. The dependence between the light sum of chemiluminescence and the content of active oxygen absorbed by samples of plant oils (rapeseed, soybean and sunflower) was linear. The described chemiluminescence method, due to its simplicity, convenience of measurements and lack of chemical reagents, can be a good method for examining accelerated oxidation of oils at increased temperature.
Naked oat variety of STH296 showed higher tolerance than traditional variety Bajka on short-term UV-B radiation (UV-BBe=11 kj-m2) on the stage of primary photosynthesis reaction recorded using chlorophyll fluorescence induction of the leaves.
This paper presents the description and application of examples of a measuring set for recording ultra-weak chemiluminescence of food products.
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