Types of ectomycorrhizae on beech seedlings (Fagus sylvatica L.) in rhizotrons

Natural processes or human activities affect environmental conditions, as reflected in the structure of the communities and the level of ectomycorrhizalfungi. The aim of the study was to determine the potential impacts of several temperature regimes of air and soil (substrate) on the occurrence and species diversity of ectomycorrhizal fungi in symbiosis and in the substrate. For this purpose, we analyzed the occurrence of types of ectomycorrhizae on beech seedlings in rhizotrons exposed to four different environmental temperature conditions: 1) air 15-25°C, 2) air 15-25°C in combination with cooling of roots for 5°C, 3) elevated air temperature from 30-50°C, and 4) ambiental conditions (air temperature in Ljubljana). Types of ectomycorrhizae were identified with a combined approach of anatomical morphological characterisation and with analysis of molecular markers (ITS1-5.8S rDNA-ITS2 ribosomal region in rDNA). We identified a total of 6 types of ectomycorrhizae on 51 root tips on 40 beech seedlings. The diversity of ectomycorrhizal types was the highest in terms of near-optimal growth conditions of beech. Most similar as far as species diversity of ectomycorrhizal fungi are concerned were the experiments with air temperature of 15-25°C with or without cooling of the root system. The commonest ectomycorrhizal species was Hebeloma sacchariolens, which was also the most commonly seen species in fine roots of dead plants. Selected species of ectomycorrhizal fungi were further substantiated with DGGE method in all analyzed substrate samples

Types of ectomycorrhizae on beech seedlings (Fagus sylvatica L.) in rhizotrons

Naravni procesi ali dejavnost človeka vplivajo na razmere v okolju, kar se zrcali v sestavi ektomikoriznih združb. V raziskavi smo želeli ugotavljati morebitne vplive več temperaturnih režimov zraka in tal (substrata) na pojavljanje in vrstno pestrost tipov ektomikorize na koreninskih vršičkih sadik bukve in v substratu. V ta namen smo analizirali pojavljanje tipov ektomikorize na sadikah bukve v rizotronih, izpostavljenih štirim temperaturnim razmeram v okolju: 1.) zrak 15-25 °C2.) zrak 15-25 °C v kombinaciji s hlajenim koreninskim sistemom za 5 °C3.) povišana temperatura zraka od 30-50 °C in 4.) zunanja (ambientalna) temperatura zraka v Ljubljani. Tipe ektomikorize smo identificirali s kombiniranim pristopom po anatomsko morfoloških znakih in z analizo molekularnih markerjev (ITS1-5.8S rDNK-ITS2 ribosomalna regija v rDNK). Na 51 koreninskih vršičkih 40 sadik smo identificirali 6 tipov ektomikorize. Pestrost ektomikoriznih tipov je bila največja pri razmerah blizu optimalnih za rast bukve. Po vrstni sestavi združbe ektomikoriznih gliv sta si najbolj podobna poskusa s temperaturo zraka15-25 °C z ali brez hlajenja koreninskega sistema. Najpogostejša ektomikorizna vrsta je bila Hebeloma sacchariolens, ki je bila tudi najpogosteje opažena vrsta na drobnih koreninah odmrlih sadik. Izbrane vrste ektomikoriznih gliv smo z metodo DGGE dokazali tudi v vseh analiziranih vzorcih substrata.Natural processes or human activities affect environmental conditions, as reflected in the structure of the communities and the level of ectomycorrhizalfungi. The aim of the study was to determine the potential impacts of several temperature regimes of air and soil (substrate) on the occurrence and species diversity of ectomycorrhizal fungi in symbiosis and in the substrate. For this purpose, we analyzed the occurrence of types of ectomycorrhizae on beech seedlings in rhizotrons exposed to four different environmental temperature conditions: 1) air 15-25°C, 2) air 15-25°C in combination with cooling of roots for 5°C, 3) elevated air temperature from 30-50°C, and 4) ambiental conditions (air temperature in Ljubljana). Types of ectomycorrhizae were identified with a combined approach of anatomical morphological characterisation and with analysis of molecular markers (ITS1-5.8S rDNA-ITS2 ribosomal region in rDNA). We identified a total of 6 types of ectomycorrhizae on 51 root tips on 40 beech seedlings. The diversity of ectomycorrhizal types was the highest in terms of near-optimal growth conditions of beech. Most similar as far as species diversity of ectomycorrhizal fungi are concerned were the experiments with air temperature of 15-25°C with or without cooling of the root system. The commonest ectomycorrhizal species was Hebeloma sacchariolens, which was also the most commonly seen species in fine roots of dead plants. Selected species of ectomycorrhizal fungi were further substantiated with DGGE method in all analyzed substrate samples

Effect of temperature and CO [sub] 2 on the dynamics of growth and cell activity of ectomycorrhizal fungi of beech Fagus sylvatica L.

V raziskavi smo želeli ugotoviti vpliv temperature zraka in tal ter koncentracij CO2 tako na sadike bukve kot tudi na ektomikorizne glive (ECM). Poskus smo zastavili na enoletnih sadikah bukve Fagus sylvatica L., posajenih v rizotrone pri različnih temperaturah: v klimatizirani komori (15-20 °C) brez dodatnega hlajenja korenin (CR-) in z dodatnim hlajenjem korenin za 4-5 °C (CR+), v rastlinjaku s povišanimi temperaturami zraka (GH) in zunaj (OUT), kjer so bile sadike izpostavljene naravnim temperaturam zraka. Na sadikah smo izvajali nedestruktivne analize korenin tekom poskusa in destruktivno analizo celotnih sadik ob koncu tri-letnega poskusa. Največji delež drobnih korenin, več kot 98% in najmanjši povprečni premer korenin so imele sadike v rastlinjaku. Delež mikoriznih korenin je bil v tretmajih CR+, CR- in GH med 10,3% in 11,4%, medtem ko je bilo v tretmaju zunaj za polovico manj mikoriznih korenin (5%). Za opis vplivov temperatur in povišanih koncentracij CO2 v zraku na koreninske sisteme in nadzemni del sadik smo izračunali indekse rasti. Dokazali smo značilen (p<0,05) vpliv temperature tal na specifično dolžino korenin in značilno (p<0,001) zmanjšanje specifične površine listov in razmerja listne površine zaradi povišanih koncentracij CO2 Mikorizne korenine smo opisali z anatomsko-morfološko metodo in nadaljevali z molekulskimi in filogenetskimi analizami identifikacije ECM. Do rodu smo identificirali 114 ECM. Z uporabo dvofotonskega konfokalnega laserskega mikroskopa in barvilom ELF-97% smo ugotavljali pojavljanje in aktivnost na površino vezane kisle fosfataze pri izbranih eksploracijskih tipih (CT ET, SD-ET, MD-ET, LD-ET). Dokazali smo, da je pojavljanje kisle fosfataze značilno različno (p<0,001) pri posameznih eksploracijskih tipih, medtem ko temperatura nima značilnega vpliva. Z izotopskimi analizami %15N in %13C v rastlinskih tkivih, mikorizi in substratu smo želeli ugotoviti tok ogljika in dušika med rastlino in glivo in vpliv okoljskih dejavnikov nanj. Potrdili smo dejstvo, da na pestrost in delovanje mikoriznih gliv vplivajo tako temperatura kot povišana koncentracija CO2. Encimska aktivnost eksploracijskih tipov ni pogojena le z okoljskimi dejavniki, temveč tudi s funkcijo ektomikorizne glive, ki jo le-ta opravlja v celotnem sistemu.In present study, the impact of air and soil temperature and CO2 concentration on beech seedlings and on ectomycorrhizal fungi (ECM) was studied. The experiment was conducted on one year old beech seedlings (Fagus sylvatica L.) planted into rhizotrons and exposed to different temperature: cooled chamber (15-20 °C) without cooling of roots (CR-) and with additional cooling of roots for 4-5 °C (CR+), greenhouse (GH) with elevated temperatures and outside (OUT).. During the experiment nondestructive analyzes were made, while in the end of tree-year experiment destructive analyzes of whole seedlings was performed. The highest proportion of fine roots, more than 98% and the lowest average root diameter were observed in GH. In CR+, CR- and GH between 10,3% and 11,4% of mycorrhizal roots were observed, while OUT were for half less mycorrhizal roots (5%). From the obtained measurements different growth parameters were recorderd. The significant impact (p<0,05) of root temperature on specific root length were observed and significant reduction (p<0,001) of specific leaf area and leaf area ratio as a consequence of elevated CO2. Mycorrhizal fungi were identified using anatomical-morphological, molecular and phylogenetic analyzes. 114 ECM types were identified. Two-photon confocal microscope and ELF-97% fluorescent dye were used for establishing the activity and occurrence of surface-bound phosphatase activity in different exploration types (CT ET, SD-ET, MD-ET, LD-ET) of ECM. Occurrence of surface bound acid phosphatase was significant (p<0,001) between ET, while temperature had no significant effect. The %15N in %13C analyzes in different parts of plant tissues, mycorrhizal fungi and soil were used to establish nitrogen and carbon flow between fungi and host plant and the influence of environmental conditions on it. Mycorrhizal fungi are very diverse group influenced by temperature and elevated CO2 concentrations. Enzymatic activity of exploration types depended on environmental factors and of function of ectomycorrhizal fungi that they had in the system

Different belowground responses to elevated ozone and soil water deficit in three European oak species (Quercus ilex, Q. pubescens and Q. robur)

Effects on roots due to ozone and/or soil water deficit often occur through diminished belowground allocation of carbon. Responses of root biomass, morphology, anatomy and ectomycorrhizal communities were investigated in seedlings of three oak species: Quercus ilex L., Q. pubescens Willd. and Q. robur L., exposed to combined effects of elevated ozone (ambient air and 1.4 x ambient air) and water deficit (100% and 10% irrigation relative to field capacity) for one growing season at a free-air ozone exposure facility. Effects on root biomass were observed as general reduction in coarse root biomass by -26.8 % and in fine root biomass by -13.1 % due to water deficit. Effect on coarse root biomass was the most prominent in Q. robur (-36.3 %). Root morphological changes manifested as changes in proportions of fine root (<2 mm) diameter classes due to ozone and water deficit in Q. pubescens and due to water deficit in Q. robur. In addition, reduced fine root diameter (-8.49 %) in Q. robur was observed under water deficit. Changes in root anatomy were observed as increased vessel density (+18.5 %) due to ozone in all three species, as reduced vessel tangential diameter (-46.7 %) in Q. ilex due to interaction of ozone and water, and as generally increased bark to secondary xylem ratio (+47.0 %) due to interaction of ozone and water. Water deficit influenced occurrence of distinct growth ring boundaries in roots of Q. ilex and Q. robur. It shifted the ectomycorrhizal community towards dominance of stress-resistant species, with reduced relative abundance of Tomentella sp. 2 and increased relative abundances of Sphaerosporella brunnea and Thelephora sp. Our results provide evidence that expression of stress effects varies between root traitstherefore the combined analysis of root traits is necessary to obtain a complete picture of belowground responses