The aim of the present work was to evaluate non-enzymic antioxidants during natural and artificially modulated senescence. Senescence of bean (Phaseolus vulgaris L. cv. Jantar) cotyledons was modulated by UV C irradiation or by the decapitation of plants apices. The content of beta-carotene and zeaxanthin decreased in control and decapitated plants but in UV C irradiated plants these contents increased. The degree of de-epoxidation increased in all cultivations with age. The content of total glutathione (sum of reduced and oxidized) sharply decreased in bean cotyledons grown in all conditions. Interestingly, the content of total ascorbate increased at the end of cotyledon life span of control and decapitated plants but decreased in UV plants. Decrease of reduced/oxidized ratio of ascorbate and glutathione during cotyledon ageing confirmed increasing oxidative stress during senescence in all cultivations.

• MeSH
• antioxidancia metabolismus   MeSH
• beta-katenin metabolismus   MeSH
• epoxidové sloučeniny metabolismus   MeSH
• fazol růst a vývoj   metabolismus   MeSH
• molekulová hmotnost MeSH
• oxidace-redukce MeSH
• xanthofyly metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antioxidancia MeSH
• beta-katenin MeSH
• epoxidové sloučeniny MeSH
• xanthofyly MeSH

Reactive oxygen species are known to increase in plant senescence. We investigated the participation of antioxidative enzymes in initiation of cotyledon senescence. Senescence of bean (Phaseolus vulgaris L.) cotyledons was modulated by UV C irradiation and by the decapitation of plant apices. Senescence was accompanied by a decrease of protein content and by a decrease of photochemical efficiency. A drop in activity of antioxidative enzymes preceded the onset of senescence in control plants. In cotyledons with prolonged life span, the decrease of antioxidant activities and the markers of senescence onset appeared at a similar age as in controls. Thus we presumed that the period from senescence initiation to cotyledon abscission was extended. On the other hand, in UV C irradiated plants we did not observe actual senescence initiation, and antioxidant enzymes although elevated, did not effectively play their role. The decrease of antioxidant enzymes activity and the markers of senescence appeared at a similar age both in control and in decapitated (D) plants, so we can presume that we prolonged mainly the period from senescence onset to cotyledon abscission in D plants. In UV C irradiated plants the antioxidative enzymes were probably destroyed before the process of senescence could begin.

• MeSH
• antioxidancia metabolismus   MeSH
• askorbátperoxidasa MeSH
• fazol růst a vývoj   metabolismus   MeSH
• glutathionreduktasa metabolismus   MeSH
• izoenzymy metabolismus   MeSH
• katalasa metabolismus   MeSH
• peroxidasy metabolismus   MeSH
• rozpustnost MeSH
• superoxiddismutasa metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antioxidancia MeSH
• askorbátperoxidasa MeSH
• glutathionreduktasa MeSH
• izoenzymy MeSH
• katalasa MeSH
• peroxidasy MeSH
• superoxiddismutasa MeSH

New androstane brassinosteroids with 17beta-ester groups - butyrates, heptafluorobutyrates, and laurates (4-18) - were prepared. Brassinolide activity was evaluated using both the bean second internode bioassay and the rice lamina inclination test. Brassinosteroid 16 was found to be the most active by the bean second internode bioassay. This activity in the bean second internode bioassay corresponded with the field yield, while the RLIT bioassay does not.

• MeSH
• androstany chemická syntéza   chemie   farmakologie   MeSH
• biotest MeSH
• brassinosteroidy MeSH
• butyráty chemie   MeSH
• cholestanoly chemická syntéza   chemie   farmakologie   MeSH
• esterifikace MeSH
• fazol účinky léků   růst a vývoj   MeSH
• fluorokarbony chemie   MeSH
• laurany chemie   MeSH
• magnetická rezonanční spektroskopie MeSH
• molekulární struktura MeSH
• rýže (rod) účinky léků   růst a vývoj   MeSH
• steroidy heterocyklické chemická syntéza   chemie   farmakologie   MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• androstany MeSH
• brassinolide MeSH Prohlížeč
• brassinosteroidy MeSH
• butyráty MeSH
• cholestanoly MeSH
• fluorokarbony MeSH
• laurany MeSH
• perfluorobutyric acid MeSH Prohlížeč
• steroidy heterocyklické MeSH