chlorophyll-a and potassium-nitrate

Accumulation of lead (Pb) in agricultural soils has become a major factor for reduced crop yields and poses serious threats to humans consuming agricultural products. The present study investigated the effects of KNO. Pb exposure markedly reduced the growth of maize seedlings and resulted in higher Pb accumulation in roots than shoots. Pretreatment of seeds with KNO. Maize accumulates more Pb in roots than shoot at early growth stages. Priming of seeds with KNO

Topics: Antioxidants; Carotenoids; Chlorophyll; Food Contamination; Germination; Lead; Nitrates; Plant Roots; Potassium Compounds; Seedlings; Seeds; Soil Pollutants; Zea mays

The present study suggests that the effect of silver coated polyester film fixed in culture racks serves as a reflector of light intensity on Spirulina platensis cultivation, using of KNO(3) and urea as nitrogen sources. The use of light reflector (LR) gave light intensity of 4.8-6.0klux and the reduction in number of tube light with reflector gave 2.5klux of light intensity and its effect was studied on S. platensis. Total chlorophyll productions were observed for the cultivation at light intensity of two lights with reflector. This improvement is simple, inexpensive and saves 50% electric energy by reducing the number of lights, and thus contributes to energy conservation.

Topics: Biomass; Cell Culture Techniques; Chlorophyll; Conservation of Energy Resources; Light; Nitrates; Potassium Compounds; Spirulina; Urea

A pot experiment was carried out under glasshouse conditions with common sage (Salvia officinalis L.) to investigate the interactive effects of salt stress and kinetin on growth attributes and the abundance of pigments, ions, phenolic diterpenes and α-tocopherol in leaf extracts of this species. The plants were subjected to the following four treatments: (i) control (nutrient solution), (ii) control + 10 μM kinetin, (iii) salt stress (nutrient solution + 100 mM NaCl), and (iv) salt stress + 10 μM kinetin. Kinetin was applied as a foliar fertilizer. Salt stress reduced water contents, photosynthetic activity and pigment contents of sage leaves. In addition, it increased Na(+) contents, and reduced those of Ca(2+) and K(+) in leaves. Salt stress reduced carnosic acid and 12-O-methyl carnosic acid contents in leaves, while it did not affect carnosol and α-tocopherol contents. Foliar applications of kinetin seemed to counterbalance or alleviate the stress symptoms induced by salinity, improving ion and pigment contents, while leaf phenolic diterpene (mainly carnosol) and α-tocopherol contents also increased in both control and NaCl-treated plants; still this effect was much more obvious in salt-treated plants. A similar effect was also obtained when plants were sprayed with KNO(3) or Ca(NO(3))(2), thus suggesting that kinetin effects were at least partly due to an improvement of ion homeostasis. Kinetin applications resulted in increased transcript levels of the isoprenoid and tocopherol biosynthetic genes, DXPRI and VTE2 and VTE4 in control plants, but not in NaCl-treated plants. We conclude that kinetin can alleviate the negative impact of salt on sage plants cultivated under arid environments with salinity problems.

Topics: Abietanes; alpha-Tocopherol; Antioxidants; Calcium Compounds; Chlorophyll; Diterpenes; Fertilizers; Gene Expression Regulation, Plant; Genes, Plant; Homeostasis; Kinetin; Nitrates; Photosynthesis; Plant Extracts; Plant Leaves; Plant Stomata; Plant Transpiration; Potassium Compounds; RNA, Plant; Salt-Tolerant Plants; Salvia officinalis; Sodium Chloride; Stress, Physiological; Vitamin E

Arthrospiraplatensis was cultivated in minitanks at 13 klux, using a mixture of KNO(3) and NH(4)Cl as nitrogen source. Fed-batch daily supply of NH(4)Cl at exponentially-increasing feeding rate allowed preventing ammonia toxicity and nitrogen deficiency, providing high maximum cell concentration (X(m)) and high-quality biomass (21.85 mg chlorophyll g cells(-1); 20.5% lipids; 49.8% proteins). A central composite design combined to response surface methodology was utilized to determine the relationships between responses (X(m), cell productivity and nitrogen-to-cell conversion factor) and independent variables (KNO(3) and NH(4)Cl concentrations). Under optimum conditions (15.5mM KNO(3); 14.1mM NH(4)Cl), X(m) was 4327 mg L(-1), a value almost coincident with that obtained with only 25.4mM KNO(3), but more than twice that obtained with 21.5mM NH(4)Cl. A 30%-reduction of culture medium cost can be estimated when compared to KNO(3)-batch runs, thus behaving as a cheap alternative for the commercial production of this cyanobacterium.

Topics: Ammonia; Ammonium Chloride; Biomass; Biotechnology; Carbon; Chlorophyll; Hydrogen-Ion Concentration; Lipids; Multivariate Analysis; Nitrates; Nitrogen; Potassium Compounds; Proteins; Regression Analysis; Spirulina; Time Factors

This study investigated if some nitrogen (N) compounds commonly used as fertilizers (KNO3, NH4NO3, (NH4)2SO4) cause chlorophyll degradation in the N-tolerant lichen Xanthoria parietina and if polyamines are responsible for the N-tolerance of this species. The results showed that N excess does not cause chlorophyll degradation and suggested the absence of kinetics in the mode of action of the N compounds tested. External supply of inhibitors of polyamine biosynthesis prior to N treatments did not cause any change in the response of chlorophyll integrity, suggesting that at least chlorophyll integrity is not controlled by polyamines.

Topics: Ammonium Sulfate; Ascomycota; Chlorophyll; Dose-Response Relationship, Drug; Fertilizers; Nitrates; Nitrogen; Polyamines; Potassium Compounds; Time Factors

The sensitivity of lichens measuring photosynthetic efficiency and polyamines as modulator of nitrogen stress tolerance was investigated. Two lichen species with a markedly different tolerance to nitrogen compounds, namely Evernia prunastri (L.) Ach. and Xanthoria parietina (L.) Th.Fr., were incubated with deionized water (control) and solutions of KNO(3), NH(4)NO(3) and (NH(4))(2)SO(4) and then exposed to different light conditions. The F(v)/F(m) parameter (maximum quantum efficiency of photosystem II) was used as stress indicator. The results showed that F(v)/F(m) values, in the produced experimental conditions, were independent from the light gradient. Photosynthetic efficiency of E. prunastri was impaired by high ammonium concentrations, while nitrate had no effect; X. parietina was hardly influenced by nitrogen compounds. External supply of polyamines reduced the sensitivity of E. prunastri, while polyamine inhibitors reduced the tolerance of X. parietina to NH(4)(+), suggesting that polyamines play an important role in modulating the sensitivity/tolerance to nitrogen stress.

Topics: Adaptation, Physiological; Ammonium Sulfate; Chlorophyll; Chlorophyll A; Dose-Response Relationship, Drug; Environmental Monitoring; Environmental Pollutants; Lichens; Light; Nitrates; Nitrogen; Photosynthesis; Photosystem II Protein Complex; Polyamines; Potassium Compounds; Stress, Physiological; Time Factors

Glancing angle laser-induced fluorescence was used to follow the kinetics of chlorophyll loss at the air-salt water interface under the influence of visible radiation. Aqueous solutions of NaCl, NaBr, NaI, KNO(3), and NaNO(2) in a range of concentrations up to approximately 1 M were used as substrates. The first-order reaction rate depends linearly on salt concentration for the halide salts but does not vary with concentration for nitrate or nitrite salts. At the same salt concentration, the chlorophyll loss rate is greatest for the bromide-containing solutions, followed by those containing chloride and then iodide. The results are consistent with a mechanism in which photoproduced chlorophyll cations are reduced by halide anions and subsequently react with the halogen atoms thus produced. This mechanism gives a novel route for gas-phase halogenated species, and possibly nitrogen oxides, to be released to the marine boundary layer.

Topics: Air; Bromides; Chlorophyll; Halogens; Kinetics; Nitrates; Nitrites; Oxidation-Reduction; Photochemistry; Potassium Compounds; Salts; Sodium Chloride; Sodium Compounds; Sodium Iodide; Water

A sand culture experiment was conducted to answer the question whether or not exogenous KNO(3) can alleviate adverse effects of salt stress in winter wheat by monitoring plant growth, K(+)/Na(+) accumulation and the activity of some antioxidant enzymes. Seeds of two wheat cultivars (CVs), DK961 (salt-tolerant) and JN17 (salt-sensitive), were planted in sandboxes and controls germinated and raised with Hoagland nutrient solution (6 mM KNO(3), no NaCl). Experimental seeds were exposed to seven modified Hoagland solutions containing increased levels of KNO(3) (11, 16, 21 mM) or 100 mM NaCl in combination with the four KNO(3) concentrations (6, 11, 16 and 21 mM). Plants were harvested 30 d after imbibition, with controls approximately 22 cm in height. Both CVs showed significant reduction in plant height, root length and dry weight of shoots and roots under KNO(3) or NaCl stress. However, the combination of increased KNO(3) and NaCl alleviated symptoms of the individual salt stresses by improving growth of shoots and roots, reducing electrolyte leakage, malondialdehyde and soluble sugar contents and enhancing the activities of antioxidant enzymes. The salt-tolerant cultivar accumulated more K(+) in both shoots and roots compared with the higher Na(+) accumulation typical for the salt-sensitive cultivar. Soluble sugar content and activities of antioxidant enzymes were found to be more stable in the salt-tolerant cultivar. Our findings suggest that the optimal K(+)/Na(+) ratio of the nutrient solution should be 16:100 for both the salt-tolerant and the salt-sensitive cultivar under the experimental conditions used, and that the alleviation of NaCl stress symptoms through simultaneously applied elevated KNO(3) was more effective in the salt-tolerant than in the salt-sensitive cultivar.

Topics: Antioxidants; Biomass; Carotenoids; Cell Membrane Permeability; Chlorophyll; Electrolytes; Ions; Lipid Peroxidation; Malondialdehyde; Nitrates; Plant Leaves; Plant Roots; Plant Shoots; Polysaccharides; Potassium; Potassium Compounds; Salt Tolerance; Seasons; Sodium; Sodium Chloride; Solubility; Stress, Physiological; Triticum; Water

Tobacco transformants that express an antisense RBCS construct were used to investigate the consequences of a lesion in photosynthetic carbon metabolism for nitrogen metabolism and secondary metabolism. The results show that an inhibition of photosynthesis and decrease in sugar levels leads to a general inhibition of nitrogen metabolism, and dramatic changes in the levels of secondary metabolites. The response was particularly clear in plants that received excess nitrogen. In these conditions, a decrease of Rubisco activity led to an inhibition of nitrate reductase activity, accumulation of nitrate, a decrease of amino acid levels that was larger than the decrease of sugars, and a large decrease of chlorogenic acid and of nicotine, which are the major carbon- and nitrogen-rich secondary metabolites in tobacco leaves, respectively. Similar changes were seen when nitrogen-replete wild-type tobacco was grown in low light. The inhibition of nitrogen metabolism was partly masked when wild-type plants and antisense RBCS transformants were compared in marginal or in limiting nitrogen, because the lower growth rate of the transformants alleviated the nitrogen deficiency, leading to an increase of amino acids. In these conditions, chlorogenic acid always decreased but the decrease of nicotine was ameliorated or reversed. When the changes in internal pools are compared across all the genotypes and growth conditions, two conclusions emerge. First, decreased levels of primary metabolites lead to a dramatic decrease in the levels of secondary metabolites. Second, changes of the amino acid : sugar ratio are accompanied by changes of the nicotine:chlorogenic acid ratio.

Topics: Amino Acids; Carbohydrate Metabolism; Chlorogenic Acid; Chlorophyll; DNA, Antisense; Ketoglutaric Acids; Light; Nicotiana; Nicotine; Nitrate Reductase; Nitrate Reductases; Nitrates; Photosynthesis; Plant Leaves; Plant Proteins; Plants, Genetically Modified; Potassium Compounds; Propanols; Ribulose-Bisphosphate Carboxylase; Rutin