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The effect of nitrogen compounds in cultivation medium on the activity of phosphoenolpyruvate carboxylase in tobacco plants
Garčeková, Květa ; Ryšlavá, Helena (advisor) ; Synková, Helena (referee)
The metabolism of plants grown in the cultivation medium is influenced by its composition and availability of CO2. In this project the effect of cultivation medium on the activity phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31), NADP-malic enzyme (NADP-ME, EC 1.1.1.40), pyruvate, phosphate dikinase (PPDK, EC 2.7.9.1) and enzymes of nitrogen metabolism: nitrate reductase (NR, EC 1.7.1.1), glutamine synthetase (GS, EC 6.3.1.2), glutamate synthase (GOGAT, EC 1.4.1.13) and glutamate dehydrogenase (GDH, EC 1.4.1.2) was studied. The tobacco plant Nicotiana tabacum L., cv. Petit Havana SR1 were grown in vitro in containers fitted with a filter, which caused limited access of CO2. The cultivation medium was modified Murashige-Skoog agar with decreased amounts of phosphate, nitrate, ammonium, or with casein as source of nitrogen and with or without of 1.5% sucrose as additional carbon source Activity of PEPC was higher in plants grown in medium in the presence of sucrose. Reduced concentrations of phosphates, nitrates or NH4 + ions or when casein was the only source of N in medium caused decreased activity of PEPC. Under these conditions, also activity of NADP-ME and of enzymes of nitrogen metabolism: NR, GS decreased. Activity of all enzymes was also negatively affected by limited CO2. On the other...
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The effect of temperature and humidity on metabolism of Festuca rubra
Vaverová, Kateřina ; Ryšlavá, Helena (advisor) ; Synková, Helena (referee)
Factors of environment such as availability of water, nutrients, temperature and sunlight affect growth and metabolism of plants. The populations of the Festuca rubra L. from four habitats in Norway, differing in altitude, average temperature and precipitation, were grown in climatic boxes differing in temperature and humidity. The Rubisco, shikimate dehydrogenase activity and amount of the protein were determined in the leaf samples of these plants. The specific activity of Rubisco was the lowest in leaves of Festuca plants grown in drought and elevated temperatures, but statistically significant differences between the various habitats and growth conditions were not found. The specific activity of shikimate dehydrogenase was, on the contrary, under drought conditions and elevated temperatures were the highest. The isoenzyme composition was tested by native electrophoresis. (In Czech) Key words: Rubisco, shikimate dehydrogenase, abiotic stress in plants
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The effect of nitrogen compounds in cultivation medium on growth and metabolism of tobacco plants
Křížová, Simona ; Ryšlavá, Helena (advisor) ; Synková, Helena (referee)
Availability of nitrogenic compounds in cultivation medium affects metabolism of plants. Plants Nicotiana tabacum L., Petit Havana SR1 were grown in vitro in Murashige- Skooge agar, with the lack of inorganic nitrogen in medium, with the organic nitrogen as the only source of nitrogen - amino acid glutamine or protein casein. I studied the activity of the enzymes related with the assimilation and metabolism of nitrogen (NR, GS, GOGAT, NAD+-GDH and NADP+-GDH) and also the enzymes of Hatch-Slack cycle (PEPC, NADP-ME, PPDK). These groups were grown in two varieties with or without the presence of 1,5% saccharose as an additional source of carbon. Plants stressed by the lack of nitrogenic compounds in medium showed a decrease in activities of all enzymes participating in nitrogenic metabolism and some enzymes of Hatch-Slack cycle (NR, GS, GOGAT, NAD+-GDH, NADP+-GDH, PEPC, NADP- ME) according to control plants. The only exception was PPDK whose activity slightly increased given the control plants. Casein as the only source of the nitrogen was metabolized, but plants grew slower than the control plants. Activities of all studied enzymes were lower the only exceptions were GS and NADP-ME whose activity increased. The utilization of glutamine by plants increased the activities of NR, PEPC, NADP-ME i PPDK...
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The effect of nitrogen compounds in cultivation medium on the activity of phosphoenolpyruvate carboxylase in tobacco plants
Garčeková, Květa ; Ryšlavá, Helena (advisor) ; Synková, Helena (referee)
The metabolism of plants grown in the cultivation medium is influenced by its composition and availability of CO2. In this project the effect of cultivation medium on the activity phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31), NADP-malic enzyme (NADP-ME, EC 1.1.1.40), pyruvate, phosphate dikinase (PPDK, EC 2.7.9.1) and enzymes of nitrogen metabolism: nitrate reductase (NR, EC 1.7.1.1), glutamine synthetase (GS, EC 6.3.1.2), glutamate synthase (GOGAT, EC 1.4.1.13) and glutamate dehydrogenase (GDH, EC 1.4.1.2) was studied. The tobacco plant Nicotiana tabacum L., cv. Petit Havana SR1 were grown in vitro in containers fitted with a filter, which caused limited access of CO2. The cultivation medium was modified Murashige-Skoog agar with decreased amounts of phosphate, nitrate, ammonium, or with casein as source of nitrogen and with or without of 1.5% sucrose as additional carbon source Activity of PEPC was higher in plants grown in medium in the presence of sucrose. Reduced concentrations of phosphates, nitrates or NH4 + ions or when casein was the only source of N in medium caused decreased activity of PEPC. Under these conditions, also activity of NADP-ME and of enzymes of nitrogen metabolism: NR, GS decreased. Activity of all enzymes was also negatively affected by limited CO2. On the other...
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Enhanced plant tolerance after ABA application
Pospíšilová, Jana ; Synková, Helena ; Baťková, Petra ; Haisel, Daniel ; Pešek, Bedřich
Critical period during micropropagation is often ex vitro transfer. The aim of this research was to determine whether exogenous abscisic acid (ABA) applied immediately after ex vitro transfer of in vitro grown tobacco regenerants can not only decrease transpiration rate and so partially eliminate their wilting but also ameliorate photoinhibition and oxidative stress. After ABA application, ABA content in tobacco leaves increased considerably, stomatal conductance and transpiration rate decreased more than in control plants and their wilting was limited. Chlorophyll and -carotene contents were higher in these plants, but the content of xanthophyll cycle pigments was not increased. However, the degree of xanthophyll cycle pigments deepoxidation was decreased what also suggested less stress in these plants. Applied ABA stimulated activities of some antioxidative enzymes but not immediately after ex vitro transfer.
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