Publications by authors named "Jan Kepczynski"

KAR, at very low concentration (3x10 M) released dormancy in Avena fatua caryopses, which was expressed in almost complete emergence of coleorhiza (CE) and radicle (RE) just after three days of germination. The dormancy-releasing effect of KAR was associated with an increased activity of ENDO-β-MANNANASE (MAN; EC 3.2.

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The dormancy release by KAR is associated with a reduction of coleorhiza and radicle sensitivity to ABA as well as with reduction the ABA/GA ratio in the coleorhiza, by a decrease content of ABA, and in the radicle, by a decrease the ABA and an increase of the GA contents. Both, karrikin 1 (KAR) and gibberellin A (GA), release dormancy in Avena fatua caryopses, resulting in the emergence of coleorhiza (CE) and radicle (RE). Moreover, KAR and GA stimulate CE and RE in the presence of abscisic acid (ABA), the stimulation being more effective in CE.

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Plant-derived smoke and smoke water (SW) can stimulate seed germination in numerous plants from fire-prone and fire-free areas, including cultivated plants and agricultural weeds. Smoke contains thousands of compounds; only several stimulants and inhibitors have been isolated from smoke. Among the six karrikins present in smoke, karrikin 1 (KAR) seems to be key for the stimulating effect of smoke.

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NO releases caryopsis dormancy in Avena fatua, the effect being dependent on the level of dormancy. The NO effect involves also the reduction of caryopsis sensitivity to ABA and to a decrease in the ABA to GA ratio due to a decrease in ABA levels and the lack of effect on GA levels before germination is completed. Nitric oxide (NO) from various donors (i.

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The dormancy release in Avena fatua caryopses was associated with a reduction in the ABA content in embryos, coleorhiza and radicle. The coleorhiza proved more sensitive to KAR and less sensitive to ABA than the radicle. The inability of dormant caryopses and ABA-treated non-dormant caryopses to complete germination is related to inhibition and delayed of cell-cycle activation, respectively.

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Germination of primary dormant wild oat caused by KAR or GA is associated with ACC accumulation and increased ethylene production shortly before radicle protrusion as a result of the non-transcriptional and transcriptional activation of ACS and ACO enzymes, respectively. Response to both compounds involves the modulation of ethylene sensitivity through ethylene receptor genes. Harvested Avena fatua caryopses are primary dormant and, therefore, germinated poorly at 20 °C.

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A simple and rapid method involving flow cytometry and NO-specific probe (DAF-FM DA) proved useful for detection and determination of intracellular NO production in Medicago truncatula suspension cells and leaves as well as in cells of Avena fatua, Amaranthus retroflexus embryos and leaves. The measurement of nitric oxide (NO) in plant material is important for examining the regulatory roles of endogenous NO in various physiological processes. The possibility of detecting and determining intracellular NO production by flow cytometry (FCM) with 4-amino-5-methylamino-2',7'-difluorofluorescein (DAF-FM DA), an NO-specific probe in Medicago truncatula cells in suspension and leaves as well as in cells of embryos and leaves of Avena fatua L.

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Molecular studies of primary and secondary dormancy in Avena fatua L., a serious weed of cereal and other crops, are intended to reveal the species-specific details of underlying molecular mechanisms which in turn may be useable in weed management. Among others, quantitative real-time PCR (RT-qPCR) data of comparative gene expression analysis may give some insight into the involvement of particular wild oat genes in dormancy release, maintenance or induction by unfavorable conditions.

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Plant-derived smoke - butenolide, called at present karrikin 1 (KAR) is known as an important inductor of seed germination and seedling growth. In this study, tricyclic butenolides were synthesized and their effects on germination of dormant and non-dormant Avena fatua caryopses were compared, as were also their effects versus those of KAR on seedling growth. KAR was found to be most effective and to completely remove dormancy.

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The induction of dormancy release and germination of Avena fatua caryopses by KAR 1 involves ABA degradation to phaseic acid. Both, KAR 1 and GA 3 , control the AsA-GSH cycle, DNA replication and accumulation of β-tubulin in embryos before caryopses germination. Avena fatua caryopses cannot germinate in darkness at 20 °C because of dormancy, but karrikinolide-1 (KAR1), a compound in plant-derived smoke, and gibberellic acid (GA3) induced an almost complete germination.

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Avena fatua L. caryopses did not germinate at 20 °C in darkness because they were dormant. However, they were able to germinate in the presence of karrikinolide (KAR1), a key bioactive compound present in smoke, and also in the presence of gibberellin A3 (GA3), a commonly known stimulator of seed germination.

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Endogenous JA production is not necessary for wound-induced expression of JA-biosynthetic lipase genes such as DAD1 in Arabidopsis. However, the JA-Ile receptor COI1 is often required for their JA-independent induction. Wounding is a serious event in plants that may result from insect feeding and increase the risk of pathogen infection.

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In our recent studies we have evidenced that repression of ADP-ribosylation factor (ARF) in potato plants results in 14-3-3 gene activation. The significant alteration in plant phenotype and in carbohydrate content clearly indicates that there may also be changes in other metabolite syntheses. In this paper we present the data on contents of compounds, occurring in transgenic potato tubers from field trial, known to be important for the human diet.

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