|
|
Connection between abiotic stress and NADP-dependent enzymes in plants
Plisková, Veronika ; Hýsková, Veronika (advisor) ; Kubíčková, Božena (referee)
Salt stress in plants is accompanied with decreased growth caused by lowered leaf water potential, closed stomata and thus reduced photosynthesis producing NADPH. However, NADPH is indispensable coenzyme for biosynthetic processes (e.g. biosynthesis of osmotically active compounds decreasing influence of stress) and for antioxidant system. In this study it was examined, whether NADP-dependent enzymes: glucose-6- phosphate dehydrogenase (G6PDH), NADP-isocitrate dehydrogenase (NADP-ICDH), NADP-malic enzyme (NADP-ME) and NADP-shikimate dehydrogenase (SDH), producing NADPH are involved in plant defence response against 100 mM NaCl. Three different model plants were used: Pisum sativa L., Phaseolus vulgaris L. and Cucumis sativa L. While in leaves of pea and bean plants salt stress caused rather decreased activities of particular NADP-dependent enzymes (especially of G6PDH and NADP-ICDH), in leaves of cucumber 9th and 11th day of stress condition were found increased activities of all studied enzymes. Simultaneously the Na+ content in salt-stressed plants was analysed by atomic emission spectrometry.
|
|
|
The effect of abiotic stress on cucumber plants (Cucumis sativa L.)
Plisková, Veronika ; Hýsková, Veronika (advisor) ; Müller, Karel (referee)
The exposure of plants to high salt concentrations causes accumulation of sodium ions. This leads to the inability of the plants to uptake water, a disturbance of ion homeostasis, a decrease in photosynthesis and oxidative stress. As a result of the salt stress, the availability of NADPH decreases. The adaptation to the concentrations of salt depends on plant's ability to compensate for the decreased availability of NADPH, which can be further used in antioxidative cycles and the synthesis of antioxidative compounds and osmoprotectants. In this work, the reduction of relative water content, a decrease in the Rubisco enzyme activity, an increase of Hsp70 in the leaves and an increase in the accumulation of sodium ions was shown in cucumber plants (Cucumis sativa L. convar. Jogger F1) exposed to salt stress (100 mM NaCl). As a consequence of salt stress, an increase in the activity of NADPH providing enzymes was found. Particularly on the second and third day of salt stress, an increase in the activity (up to 270 %) of: NADP-isocitrate dehydrogenase, glucose-6-phosphate dehydrogenase, NADP-malic enzyme, non-phosphorylating glyceraldehyde-3-phosphate dehydrogenase in leaves was detected. The activity of less abundant NADP-dehydrogenases (glucose 1-dehydrogenase, gluconate 2-dehydrogenase, galactose...
|
|
|
Connection between abiotic stress and NADP-dependent enzymes in plants
Plisková, Veronika ; Hýsková, Veronika (advisor) ; Kubíčková, Božena (referee)
Salt stress in plants is accompanied with decreased growth caused by lowered leaf water potential, closed stomata and thus reduced photosynthesis producing NADPH. However, NADPH is indispensable coenzyme for biosynthetic processes (e.g. biosynthesis of osmotically active compounds decreasing influence of stress) and for antioxidant system. In this study it was examined, whether NADP-dependent enzymes: glucose-6- phosphate dehydrogenase (G6PDH), NADP-isocitrate dehydrogenase (NADP-ICDH), NADP-malic enzyme (NADP-ME) and NADP-shikimate dehydrogenase (SDH), producing NADPH are involved in plant defence response against 100 mM NaCl. Three different model plants were used: Pisum sativa L., Phaseolus vulgaris L. and Cucumis sativa L. While in leaves of pea and bean plants salt stress caused rather decreased activities of particular NADP-dependent enzymes (especially of G6PDH and NADP-ICDH), in leaves of cucumber 9th and 11th day of stress condition were found increased activities of all studied enzymes. Simultaneously the Na+ content in salt-stressed plants was analysed by atomic emission spectrometry.
|
guest ::
