Enhancement of biomass production, salinity tolerance and nutraceutical content of spinach (Spinacia oleracea L.) with the cuticular wax constituent triacontanol

The present study investigates the effect of foliar application of triacontanol (TRIA) on various physiological parameters with regard to crop yield and quality attributes of spinach (Spinacia oleracea L.) under normal growth conditions and salinity stress. Plantlets were grown for 21 days in perlite-containing pots supplemented with Hoagland’s nutrient solution, then they were subjected to 0 (control) or 150 mM NaCl. Two concentrations of TRIA (25 nM and 1 μM) were applied during seed germination and as foliar spray treatment, in itself or simultaneously with salt stress at 4-day intervals for three weeks. Exogenous application of TRIA enhanced germination energy and capacity, as well as shoot and root biomass of young spinach plants. Inhibition of net CO2 assimilation (Pn) and of potential quantum yield of photosystem II (Fv/Fm), caused by salt stress, was significantly reduced by treatment with triacontanol. Increment of carotenoid pigment and ascorbate (vitamin C) content, as well as reduction of membrane lipid peroxidation due to triacontanol treatment improves the health-promoting quality of spinach leaves developed under high salinity conditions. The presented results offer a novel solution for optimization of spinach cultivation on soils affected by high salinity, as well as for an increased content of health-promoting metabolites of spinach leaves upon human consumption

PHYSIOLOGICAL MARKERS OF DUCKWEED (Lemna minor L.) FOR BIOINDICATION OF WATER POLLUTION WITH COPPER AND DIURON (3-(3,4-DICHLOROPHENYL)-1,1-DIMETHYLUREA)

Abstract. Lesser duckweed (Lemna minor L.) is a cosmopolitan aquatic test plant, its growth and metabolic parameters are useful markers of the influence exerted on living organisms by changes in water quality. We have investigated the influence of water-polluting copper and herbicides on net biomass production, photosynthetic pigment content and efficiency parameters of induced chlorophyll fluorescence of duckweed. Copper decreased biomass production of duckweed only at higher concentrations (100 µM), while diuron inhibited growth even at 10 µM. With respect to the light-harvesting complexes of chloroplasts, the molar ratios between the main types of photosynthetic pigments proved to be the most sensitive markers of the impact of the applied water-polluting agents. In case of water pollution with copper and diuron, the mostly sensitive parameters of induced chlorophyll fluorescence were the potential quantum yield efficiency and the vitality index of photosynthetic apparatus, these parameters being recommended for bioindication of water pollution

STRESS-PHYSIOLOGICAL REACTIONS OF THE GREEN ALGA SCENEDESMUS OPOLIENSIS TO WATER POLLUTION WITH HERBICIDES

Abstract. The freshwater green alga Scenedesmus opoliensis proves to be a suitable bioindicator of water pollution with different herbicides. One of the best molecular markers of stress condition imposed by herbicides is overproduction of malondialdehyde resulting from lipid peroxidation in the damaged membranes. Methylviologen, a largely used pre-emergence herbicide which generates reactive oxygen species in the illuminated chloroplasts, triggers the accumulation of ascorbic acid and enhances the enzymatic activity of catalase, both of these substances being involved in the antioxidative protection of algal cells. Diuron, a herbicide that inhibits photosynthetic electron transport on the acceptor side of photosystem II, causes a decline in oxygen production and in biomass accumulation of algae. Glufosinate induces accumulation of toxic ammonia and leads to enhanced net oxygen production, associated with a low rate of carbon assimilation. Long-term exposure to micromolar concentrations of herbicides results in significant changes in the rate of cell division, in photosynthetic parameters and in the intensity of antioxidative defense. A proper bioindication of toxic effects of herbicides on algae requires a selected combination of different physiological and biochemical parameters which reflect the degree of stress exerted on living organisms by water pollution with xenobiotic organic compounds

Chemical Composition of Celandine (<i>Chelidonium majus</i> L.) Extract and its Effects on <i>Botrytis tulipae</i> (Lib.) Lind Fungus and the Tulip

In this study, the content of chelidonine and berberine alkaloids, and sterols and phenols in the Chelidonium majus plant extract were analyzed. Subsequently, the effects of the extract on the germination and growth of Botrytis tulipae fungus on nutritive medium were compared to the effects of fluconazole. The plant extract was used at the minimum inhibitory concentration on B. tulipae developed in tulip leaves and the in vivo effects were investigated. The influence of different concentrations of C. majus extract on the physiological processes of the tulip (gas exchange parameters, photosynthetic light use efficiency, and induced chlorophyll fluorescence) were also tested to assess the applicability of the extract for the protection of ornamental plants against fungal infection. Our results demonstrated that 2% celandine extract does not significantly change the gas exchange parameters (transpiration rate, carbon dioxide uptake, and stomatal conductivity) of leaves exposed for 2 h, and does not interfere with the photochemical processes in the leaves. However, in higher concentrations, it increases the transpiration rate and net carbon dioxide influx. At concentrations of 15% and 20%, the extract lowers the potential quantum yield efficiency of photosystem II and the vitality index of the photosynthetic apparatus. Therefore we recommend the use of lower concentrations (≤6%) of celandine extract for the biological protection of tulips against gray mold

Chemical Composition of Celandine (<i>Chelidonium majus</i> L.) Extract and its Effects on <i>Botrytis tulipae</i> (Lib.) Lind Fungus and the Tulip

In this study, the content of chelidonine and berberine alkaloids, and sterols and phenols in the Chelidonium majus plant extract were analyzed. Subsequently, the effects of the extract on the germination and growth of Botrytis tulipae fungus on nutritive medium were compared to the effects of fluconazole. The plant extract was used at the minimum inhibitory concentration on B. tulipae developed in tulip leaves and the in vivo effects were investigated. The influence of different concentrations of C. majus extract on the physiological processes of the tulip (gas exchange parameters, photosynthetic light use efficiency, and induced chlorophyll fluorescence) were also tested to assess the applicability of the extract for the protection of ornamental plants against fungal infection. Our results demonstrated that 2% celandine extract does not significantly change the gas exchange parameters (transpiration rate, carbon dioxide uptake, and stomatal conductivity) of leaves exposed for 2 h, and does not interfere with the photochemical processes in the leaves. However, in higher concentrations, it increases the transpiration rate and net carbon dioxide influx. At concentrations of 15% and 20%, the extract lowers the potential quantum yield efficiency of photosystem II and the vitality index of the photosynthetic apparatus. Therefore we recommend the use of lower concentrations (≤6%) of celandine extract for the biological protection of tulips against gray mold