The effect of Hg++ was studied on the arrangement and photoactivity of NADPH:protochlorophyllide oxidoreductase (POR) in homogenates of dark-grown wheat (Triticum aestivum L.) leaves. 77 K fluorescence emission spectra of the homogenates were recorded before and after the irradiation of the homogenates and the spectra were deconvoluted into Gaussian components. The mercury treatment caused a precipitation of the membrane particles, which was followed by a remarkable decrease of the fluorescence yield. 10-3 M Hg++ decreased the ratio of the 655 nm-emitting protochlorophyllide (Pchlide) form to the 633 nm-emitting form. 10-2 M Hg++ shifted the short wavelength band to 629-630 nm and a 655 nm form was observed which was inactive on irradiation. This inhibition may be caused by serious alteration of the enzyme structure resulting in the trans-localisation of NADPH within the active site of POR. and K. Lenti, F. Fodor, B. Böddi.
The identification and examination of sources of external loading are important pressure indicators for studying the nutrient balance and eutrophication of water bodies. Focusing on the eastern Gulf of Finland, this paper investigates and decomposes the sources of phosphorus, a limiting factor of eutrophication of the Gulf and its accompanying Neva Bay, and of nitrogen as pressure indicators. The eastern Gulf of Finland’s catchment basin represents Europe’s largest freshwater basin. Both point and non-point sources of pollution, as well as their current and possible withdrawals from the watershed’s nutrient loading, are considered. The investigation identifies poultry plants and animal husbandry enterprises in the coastal watershed as critical contributing sources to eutrophication in the eastern Gulf of Finland. Analyses based on such pressure indicators can help to contribute directly to future policy-making as concerns environmental protection measures and water resources planning in the eastern Gulf of Finland and other regions. and Identifikácia zdrojov externej záťaže živinami je významným indikátorom pre štúdium bilancie živín a eutrofizácie vôd. Tento príspevok prezentuje výsledky výskumu zdrojov fosforu a sodíka východnej časti Fínskeho zálivu a delty rieky Nevy, ako limitujúcich faktorov eutrofizácie. Povodie východnej časti Fínskeho zálivu je najväčším európskym zdrojom sladkej vody. V analýze sú uvažované bodové a plošné zdroje znečistenia a tiež súčasné, ale aj možné odbery vody a znečisťujúcich látok z povodia. Výskumom sa podarilo identifikovať hydinárske farmy a veľkochovy zvierat v pobrežnej zóne povodia ako kritické vzhľadom na eutrofizáciu východnej časti Fínskeho zálivu. Výsledky analýzy môžu priamo prispieť k tvorbe legislatívy týkajúcej sa ochrany životného prostredia a plánovania využitia zdrojov vody vo východnej časti Fínskeho zálivu, ale aj v iných regiónoch.