Acta Physiologiae Plantarum

Ratajczak, Ewelina; Pukacka, Stanisława

doi: 10.1007/s11738-005-0030-6pmid: N/A

The aim of this study was to determine if the loss of germinability and viability of beech (Fagus sylvatica L.) seeds stored at different variants of temperature (4, 20, and 30 °C) and relative humidity (RH: 45 and 75 %) is associated with a loss of membrane integrity and changes in lipid composition. Beech seeds stored for 9 weeks gradually lost viability at a rate dependent on temperature and humidity. The harmful effect of temperature increased with growing humidity. The loss of seed viability was strongly correlated with an increase in membrane permeability and with production of lipid hydroxyperoxides (LHPO), which was regarded as an indicator of peroxidation of unsaturated fatty acids. The condition of membranes was assessed on the basis of their permeability and the state of lipid components: phospholipids and fatty acids. During seed storage we observed a decline in concentration of individual phospholipids and fatty acids, proportional to the loss of seeds viability. We also detected a decrease in concentrations of α-tocopherol and sterols, which play an important role in protection of membranes against the harmful influence of the environment. Our results show that the germinability of beech seeds declines rapidly at temperature above 0 °C and growing humidity. This is due mainly to the loss of membrane integrity, caused by peroxidation of unsaturated fatty acids.

Todorova, Dessislava; Genkov, Todor; Vaseva-Gemisheva, Irina; Alexieva, Vera; Karanov, Emanuil; Smith, Aileen; Hall, Michael

doi: 10.1007/s11738-005-0031-5pmid: N/A

The levels of three endogenous cytokinin equivalents: zeatin (Z), iso-pentenyladenine (iP) and dihydrozeatin (dZ) in two Arabidopsis thaliana (L.) Heynh genotypes — wild type (wt) and ethylene-insensitive mutant (eti5), were compared using enzyme immunoassay (ELISA). Cytokinin content was measured after exposure to low (4 °C for 24 h in darkness) or high temperature (38 °C for 24 h in darkness). Measurements were performed immediately and 24, 48 and 120 h after treatments. It was found that at normal growth conditions eti5 plants contained more endogenous cytokinins compared to the wild type. At both temperature treatments mutant plants had decreased total cytokinin levels. Wild-type plants treated with high temperature (HT) exhibited reduced total cytokinins (with the exception of rates at 48 h), while low temperature (LT) treatment resulted in elevated total amount of the studied equivalents (except at 24 h). The obtained results suggested that HT had greater effect on cytokinin levels than LT since it caused more profound changes in the total content. We assume that this was due to the natural chilling tolerance of Arabidopsis plants.

Wawrzy czak, Danuta; Michalczuk, Lech; Sowik, Iwona

doi: 10.1007/s11738-005-0032-4pmid: N/A

Strawberry (Fragaria × ananassa Duch.) was transformed with maize IAA-glucose synthase gene (iaglu) via Agrobacterium tumefaciens using binary vector system. Incorporation of the transgene was confirmed by PCR and Southern blot analysis and its transcription by RT-PCR. Transformation resulted in a significant increase of ester-conjugated IAA level in tissue of all tranegenic plants while free IAA level was significantly lower in two trangenic clones tested and in other two it was comparable to that in wild-type plants. The level of amide-conjugated hormone was not affected by transformation with iaglu. The change in endogenous IAA metabolism affected the growth and development of transgenic strawberry plants but the effect was not fully correlated with changes in endogenous IAA level. In general, the transgenic clones were dwarfish — their leaf laminas were smaller, leaf petioles shorter and the crown diameter smaller in comparison to wild-type ones, although in one clone the difference was significant only for leaf lamina area. Shoots of all transgenic clones formed more roots in vitro than the wild-type plants and in two clones the roots were longer than in the control.

Romanowska, Elbieta; Pokorska, Berenika; Siedlecka, Maria

doi: 10.1007/s11738-005-0033-3pmid: N/A

The effects of oligomycin on photosynthesis and respiration in relation to ATP production in chloroplasts and mitochondria were investigated in protoplasts isolated from the detached pea (Pisum sativum L cv. Iłowiecki.) and barley (Hordeum vulgare L. cv. Gunilla) leaves treated 5 mM Pb(NO3)2. The oligomycin (OM), an inhibitor of oxidative phosphorylation at 0.1 µM concentration caused the inhibition of photosynthesis rate in the protoplasts from both the control and the Pb-treated pea leaves. The respiration rate and ATP/ADP ratio in the protoplasts and the activity of ATPase in mitochondria, were also diminished in the control protoplasts. These effects were not observed in the protoplasts and mitochondria isolated from the Pb-treated leaves. Oligomycin, an inhibitor of photophosphorylation at 10 µM concentration decreased ATPase activity in chloroplasts from both the control and the Pb- treated leaves.

Sachdeva, Monica; Mann, A.; Batta, S.

doi: 10.1007/s11738-005-0034-2pmid: N/A

Sugarcane cell cultures were obtained from callus formed on explants derived from young expanding leaves of two early maturing sugarcane varieties viz “CoJ83” and “CoJ86”. The cell cultures were varied with different arginine concentrations in the culture medium. For each cultivar, sucrose content with 20 µM arginine in the culture medium decreased from 3 to 5 days and then increased to 10 days after subculturing. Higher concentration of arginine in the culture medium (60 µM) decreased the sucrose content at different days after subculturing and thus significantly stimulated sucrose mobilization. The activity of sucrose synthase and sucrose phosphate synthase reached maximum while the activity of acid and neutral invertase was minimal in the culture medium with 20 µM arginine. Thus arginine at low concentration (20 µM) enables the cells to accumulate the higher level of sucrose. The optimum level of amino acids can be utilized to regulate the in vivo activity of sucrose synthase, sucrose phosphate synthase and invertase to achieve maximum sucrose accumulation in sugarcane storage tissue.

Heidenreich, Bernd; Haberer, Georg; Mayer, Klaus; Sandermann, Heinrich; Dieter, Ernst

doi: 10.1007/s11738-005-0035-1pmid: N/A

Selected cDNA clones of Arabidopsis thaliana, isolated previously by suppression subtractive hybridisation, were used to differentiate between abiotic stress factors. Changes in expression patterns of 79 genes were examined by array analysis in Arabidopsis thaliana after fumigation with ozone and after short- or long-term mercuric-ion exposure. Substantial changes in the abundance of 42 transcripts were recorded in response to the treatments, and 6 transcript clusters were observed. The abundance of 37 mRNAs was increased more then 1.5-fold, whereas that of 5 mRNAs was reduced. The abundances of 5, 6 and 9 mRNAs were specifically increased by short-term mercury application, ozone fumigation, and long-term mercuric-ion exposure, respectively. The transcription of the other 5 transcripts was induced by both ozone and short-term mercuric-ion treatment. The abundance of 10 different mRNAs was increased by the different mercuric-ion applications. Two transcripts were induced by ozone fumigation, as well as long-term, mercury treatment. Finally, 5 transcripts were repressed by ozone exposure, and 3 out of them by short-term mercuric-ion treatment. These results show that the array technique can be used to analyse the expression pattern in Arabidopsis thaliana under ozone and mercuric-ion stress. Searches against the Arabidopsis database furthermore provide a classification of most genes. In addition possible cis-acting regulatory elements were identified by an in silico approach using the MIPS Arabidopsis thaliana database.

Wolska-Mitaszko, Barbara; Molestak, Eliza; Małek, Wanda

doi: 10.1007/s11738-005-0036-0pmid: N/A

Trehalase activity (THA) was identified in the cell-free extracts of various organs of Medicago sativa: roots, roots nodules, stems and leaves, as well as in seedlings and seeds. It showed the high activity at acid pH and optimal temperature ranged from 45° to 55°C. It was also differently affected by ions, i.e. the presence of calcium stimulated this activity but it was inhibited by Zn2+ and NH 4 + . After separation by DEAE-cellulose chromatography and purification procedures, trehalase from alfalfa was purified 800 times, and Superose 12 HR gel filtration allowed to determine the molecular weight of 120 kDa for the native enzyme from the stems of alfalfa.

Sujak, Agnieszka

doi: 10.1007/s11738-005-0037-zpmid: N/A

This paper reports the results of research on the interaction between the cytochrome f of the active cytochrome b 6 f complex (incubated with Cd-, Zn-, and Ag-substituted plastocyanins) and Cu-plastocyanin. The presented studies show, that the metal derivatives of plastocyanin can have an influence on the photosynthetic electron transfer path: cytochrome b 6 f complex — photosystem I. The metal-substituted plastocyanins occupy the plastocyanin electron transfer site of the cytochrome f. The stopped-flow measurements show, that although the metal derivatives of plastocyanin do not influence the rate of cyt f- Pc electron transfer, creation of the non-electron-transfer complexes characterised by a strong binding between the cyt f and substituted plastocyanins and their slow release, dependent on the redox state of the substituted metal, results in the decrease of a turnover of the cytochrome complex.

Kargol, M.; Kargol, A.

doi: 10.1007/s11738-005-0038-ypmid: N/A

In the present study, we discussed the biophysical mechanisms of stationary water exchange with the surroundings by the Nitella translucens and Chara corallina plants. It was postulated that these plants, which subsist under total immersion in a water medium, conduct water exchange within single cells individually. With the application of the equations of mechanistic formalism for membrane transport to our investigations (Kargol and Kargol 2000, Kargol 2001, Kargol 2002, Kargol and Kargol 2003, 2003*), it was demonstrated that individual cells of these plants can simultaneously absorb and remove considerable amounts of water at constant cell volume, i.e. under stationary conditions. Water absorption is osmosis-driven, and its removal is effected by the cell turgor pressure.

Skrzypczak-Pietraszek, Ewa; Szewczyk, Agnieszka; Piekoszewska, Agata; Ekiert, Halina

doi: 10.1007/s11738-005-0039-xpmid: N/A

Cells from Echinacea purpurea (L.) Moench. (Asteraceae), Exacum affine Balf. f. (Gentianaceae), Melittis melissophyllum L. (Lamiaceae), Ruta graveolens L. and Ruta graveolens ssp. divaricata (Tenore) Gams. (Rutaceae) agitating cultures perform a biotransformation reaction on exogenously supplied hydroquinone into its β-D-glucoside — arbutin, product with valuable medicinal and cosmetic properties. The maximum content of arbutin (determined by HPLC) in the biomass from investigated cultures is 4.01; 3.44; 1.79; 2.48 and 5.07 g/100 g d.w., respectively. Nothing but Ammi majus L. (Apiaceae) cultures contain trace amounts of the product. Arbutin is accumulated in cells; it is occasionally found in media only in vestigial amounts. In most of the investigated cultures the efficiency of the biotransformation process is about 60 %.