Search

Človek z industrijo in z drugimi dejavnostmi obremenjuje okolje in vpliva na ekosisteme. Dolina dimnikov in okolica Žerjava je močno obremenjena s prekomernimi koncentracijami kovin v tleh. Glavni namen naloge je bil ugotoviti, kako različne vrste izbranih izolatov temnih septiranih endofitov DB146, DB148 in DB149, vplivajo na fiziološko stanje vrbe ive, ki raste na tleh s prekomernimi koncentracijami kovin, ter na njen privzem kovin. Z različnimi metodami smo ovrednotili koncentracije rastlinam dostopnih kovin, fosforja in organske snovi v substratu. Z meritvami koncentracij kovin in fotosinteznih pigmentov v listih smo ovrednotili privzem v rastline in fiziološko stanje ive. Ocenili smo uspešnost kolonizacije posameznih izolatov. Naši rezultati nakazujejo na močan stres, ki verjetno ni posledica prekomernih koncentracij kovin. Stres sta verjetno povečevala pomanjkanje vode ter nutrientov. Višji parametri kolonizacije izolatov DB146 in DB148 nakazujejo na boljšo toleranco teh izolatov na prekomerne koncentracije kovin in na uporabo veziklov za kopičenje in stabilizacijo kovin. Nižji parametri kolonizacije pri izolatu DB149 kažejo na drugačno biologijo in možen negativen vpliv drugih mikroorganizmov. Izsledki naše raziskave nakazujejo, da so izbrani izolati temnih septiranih endofitov, predvsem izolata DB146 in DB148, primerni za souporabo v bioremediaciji. Potrebne so nadaljnje raziskave, da bi dobro razumeli vpliv izbranih glivnih izolatov na splošno fiziološko stanje in na privzem kovin. Industrial activies in Žerjav lead to high accumulation of metals, especially Pb, Cd and Zn) in soils. Our aim was to evaluate contribution of selected isolates of dark septate endophytes on metal accumulation in plants and physiological condition of Salix caprea L. cuttings. We measured bioavailable concentrations of metals, phosphorus and organic matter in substrate. To evaluate physiological condition and metals uptake of cuttings we measured metal concentrations and photosynthetic pigments in leaves. To assess success of colonisation of selected strains we evaluated parameters of colonisation. Goat willow cuttings exhibited strong stress symptoms, which were caused probably not by excessive metal concentrations in substrate. Strong stress factors could be water and nutrient deficiency. High colonisation parameters of isolates DB146 and DB148 are suggesting better tolerance of these isolates on high metal concentrations. Low colonisation parameters of isolate DB149 are suggesting different biology of selected isolate and possible negative effect on growth of native colonisators from substrate. To conclude, our findings suggest isolates, especially DB146 and DB148, are suitable for combined use with goat willows in bioremediation processes. For better understanding of contribution of selected strains on metal uptake and physiological condition of goat willow further research is needed.

Območje Žerjava je prekomerno onesnaženo s kovinami v tleh (svinec, kadmij, cink) kot posledica dolgoletnega obratovanja talilnice svinca, ki je močno vplivala tudi na okoliško vegetacijo. Znano je, da asociacije rastlin z glivnimi endofiti ublažijo stres in s tem izboljšajo preživetje rastlin v ekstremnih okoljih. Nabrali smo vzorce korenin treh drevesnih vrst (vrbe ive, navadne breze in rdečega bora) ter pripadajoče vzorce rizosfernih tal na dveh različno onesnaženih vzorčnih ploskvah (P2 in P3). Vzorcem tal smo določili vsebnost organske snovi, rastlinam dostopnega fosforja, celokupne koncentracije kovin in pH vrednost. Na koreninskih vzorcih drevesnih vrst smo ocenili kolonizacijo z ektomikoriznimi (EM) in arbuskularno mikoriznimi (AM) glivami ter temnimi septiranimi endofiti (DSE). Pri vseh drevesnih vrstah na obeh vzorčnih ploskvah je prevladovala kolonizacija z EM glivami. Potrdili smo pozitivno korelacijo med kolonizacijo z DSE in koncentracijami kovin v tleh. Izolirali smo DNA iz posameznih EM morfotipov in s pomočjo molekularnih metod (PCR, sekvenciranje) identificirali glivne simbionte pri posameznih drevesnih vrstah. Pri vrbi so prevladovale glive iz družine Sordariaceae, pri brezi glive iz družine Thelephoraceae, pri boru pa glive iz družine Pyronemataceae. Ugotovili smo, da so razlike v mikorizni kolonizaciji in strukturi glivnih simbiontov bolj pogojene z drevesno vrsto kot z vzorčno ploskvijo (stopnjo onesnaženja). Long-term lead mining and smelting activities in Žerjav area has resulted in global metal pollution and degradation of environment. Associations of plants with fungal endophytes may alleviate stress and improve survival of plants in extreme environments. The root samples of three different tree species (goat willow, silver birch and scots pine) and their rhizosphere soils were collected at two different sampling sites (P2 and P3). The total organic content, plant accesible phosphorus, the total metal concentration and pH were measured on soil samples. Colonisation with ectomycorrhizal (EM), arbuscular mycorrhizal (AM) and dark septate endophytes (DSE) was evaluated. EM colonisation dominated in all tree species at both sampling sites. Positive correlation between the level of DSE colonisation and increased soil metal concentration was confirmed. DNA was isolated from different EM morphotypes. Fungal symbionts were identified with molecular methods (PCR, sequencing). Fungi from family Sordariaceae were the most abudant in goat willow, Thelephoraceae dominated in silver birch and Pyronemataceae were the most common in scots pine. The results show that tree species is more important factor determining mycorrhizal colonisation and fungal community structure than the sampling site (degree of pollution).