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101.
Isotopic and water relation responses to ozone and water stress in seedlings of three oak species with different adaptation strategies
Claudia Cocozza, Elena Paoletti, Tanja Mrak, Saša Zavadlav, Tom Levanič, Hojka Kraigher, Alessio Giovannelli, Yasutomo Hoshika, 2020, izvirni znanstveni članek

Povzetek: The impact of global changes on forest ecosystem processes is based on the species-specific responses of trees to the combined effect of multiple stressors and the capacity of each species to acclimate and cope with the environment modification. Combined environmental constraints can severely affect plant and ecological processes involved in plant functionality. This study provides novel insights into the impact of a simultaneous pairing of abiotic stresses (i.e., water and ozone (O3) stress) on the responses of oak species. Water stress (using 40 and 100% of soil water content at field capacity - WS and WW treatments, respectively) and O3 exposure (1.0, 1.2, and 1.4 times the ambient concentration - AA, 1.2AA, and 1.4AA, respectively) were carried out on Quercus robur L., Quercus ilex L., and Quercus pubescens Willd. seedlings, to study physiological traits (1. isotope signature [delta 13C, delta 18O and delta 15N], 2. water relation [leaf water potential, leaf water content], 3. leaf gas exchange [light-saturated net photosynthesis, Asat, and stomatal conductance, gs]) for adaptation strategies in a Free-Air Controlled Exposure (FACE) experiment. Ozone decreased Asat in Q. robur and Q. pubescens while water stress decreased it in all three oak species. Ozone did not affect delta 13C, whereas delta 18O was influenced by O3 especially in Q. robur. This may reflect a reduction of gs with the concomitant reduction in photosynthetic capacity. However, the effect of elevated O3 on leaf gas exchange as indicated by the combined analysis of stable isotopes was much lower than that of water stress. Water stress was detectable by delta 13C and by delta 18O in all three oak species, while delta 15N did not define plant response to stress conditions in any species. The delta 13C signal was correlated to leaf water content (LWC) in Q. robur and Q. ilex, showing isohydric and anisohydric strategy, respectively, at increasing stress intensity (low value of LWC). No interactive effect of water stress and O3 exposure on the isotopic responses was found, suggesting no cross-protection on seasonal carbon assimilation independently on the species adaptation strategy.
Ključne besede: ozone, gas exchange, English oak, holm oak, downy oak, Quercus ilex L., Quercus robur L., Quercus pubescens Willd
Objavljeno v DiRROS: 11.08.2020; Ogledov: 1757; Prenosov: 1079
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102.
PCR primers comparisons for a successful Tuber spp. DNA region amplification in routine identifications
Tina Unuk Nahberger, Hojka Kraigher, Tine Grebenc, 2020, izvirni znanstveni članek

Povzetek: Since late 20th century DNA sequencing became the method of choice method in precision species identification. The ITS region is one of the official fungal barcoding DNA markers, although in some cases sequencing of the ITS re-gion may, due to misidentification, mislabeling or nomen-clature errors in public databases, lead to incorrect or insuf-ficient identification, as is currently a case in the genus Tu b e r. The aim of this study was to test, which ITS primer pairs are most appropriate and optimal for Tu b e r species DNA region amplification. Thereby we (1) compared ampli-fication success for different Tu b e r species using fungal spe-cific primer pair ITS1f and ITS4 and (2) compared amplifi-cation success using different ITS primer pair combinations in amplifying DNA region an example species Tuber aesti-vum. Based on results, Tuber aestivum was one of the most reluctant Tu b e r species in this study and in most cases failed to amplify with the above primer pair. After comparing dif-ferent ITS primer pairs, we conclude that the primer pair ITS5 and ITS7 is the most appropriate primer pair for ampli-fication DNA region of T. ae stiv um as it resulted in high am-plification success from ectomycorrhizal root tips. Based on sequences, gained from public databases, we found that ITS1f and ITS6 primers have a mismatch in one base pair compared to the target sequence of Tuber aestivum, thus re-sulting in poor or no amplification success. Although prim-er pair ITS5 and ITS7 in our study was proven to be the most appropriate primer pair in amplifying DNA region Tu b e r aestivum species, further analysis about appropriateness of it for a general barcoding and identification of ectomycorrhiza in complex community samples is needed.
Ključne besede: Tuber spp., ITS region, PCR amplification, ITS primers
Objavljeno v DiRROS: 30.07.2020; Ogledov: 1596; Prenosov: 1178
.pdf Celotno besedilo (6,81 MB)
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103.
Elevated ozone prevents acquisition of available nitrogen due to smaller root surface area in poplar
Tanja Mrak, Klemen Eler, Ovidiu Badea, Yasutomo Hoshika, Elisa Carrari, Elena Paoletti, Hojka Kraigher, 2020, izvirni znanstveni članek

Povzetek: Aims Poplars are ecologically and economically important tree genus, sensitive to ozone (O3). This study aimed to investigate modifying effects of elevated O3 on poplar root response to nutrient addition. Methods In pot experiment, young trees of an O3-sensitive Oxford poplar clone (Populus maximoviczii Henry x berolinensis Dippel) growing in soil with three levels of P (0, 40 and 80 kg ha-1) and two levels of N (0 and 80 kg ha-1) were exposed to three levels of O3 (ambient - AA, 1.5 x AA, 2.0 x AA) at a free air exposure facility. After one growing season, root biomass, fine root (<2 mm) nutrient concentrations and ratios, and fine root morphology were assessed. Results Nitrogen addition resulted in an up to +100.5% increase in coarse and fine root biomass under AA, and only up to +46.3% increase under 2.0 x AA. Elevated O3 and P addition had a positive effect, while N had a negative effect on P concentrations in fine roots. Nitrogen limitation for root growth expressed as a N:P ratio was more pronounced at elevated O3. Nitrogen addition increased root surface area per soil volume by +78.3% at AA and only by +9.9% at 2.0 x AA. Conclusions Smaller root surface area per soil volume at elevated O3 prevented acquisition of available N, rendering N fertilization of young poplar plantations in such conditions economically and environmentally questionable.
Ključne besede: fine roots, nitrogen, phosphorus, Populusmaximoviczii x berolinensis, ozone, Poplar
Objavljeno v DiRROS: 16.06.2020; Ogledov: 1849; Prenosov: 1007
.pdf Celotno besedilo (775,68 KB)
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The interplay between forest management practices, genetic monitoring, and other long-term monitoring systems
Darius Kavaliauskas, Barbara Fussi, Marjana Westergren, Filipos Aravanopoulos, Domen Finžgar, Roland Baier, Paraskevi Alizoti, Gregor Božič, Evangelia V. Avramidou, Monika Konnert, Hojka Kraigher, 2018, pregledni znanstveni članek

Povzetek: The conservation and sustainable use of forests and forest genetic resources (FGR) is a challenging task for scientists and foresters. Forest management practices can affect diversity on various levels: genetic, species, and ecosystem. Understanding past natural disturbance dynamics and their level of dependence on human disturbances and management practices is essential for the conservation and management of FGR, especially in the light of climate change. In this review, forest management practices and their impact on genetic composition are reviewed, synthesized, and interpreted in the light of existing national and international forest monitoring schemes and concepts from various European projects. There is a clear need and mandate for forest genetic monitoring (FGM), while the requirements thereof lack complementarity with existing forest monitoring. Due to certain obstacles (e.g., the lack of unified FGM implementation procedures across the countries, high implementation costs, large number of indicators and verifiers for FGM proposed in the past), merging FGM with existing forest monitoring is complicated. Nevertheless, FGM is of paramount importance for forestry and the natural environment in the future, regardless of the presence or existence of other monitoring systems, as it provides information no other monitoring system can yield. FGM can provide information related to adaptive and neutral genetic diversity changes over time, on a species and/or on a population basis and can serve as an early warning system for the detection of potentially harmful changes of forest adaptability. In addition, FGM offers knowledge on the adaptive potential of forests under the changing environment, which is important for the long-term conservation of FGR
Ključne besede: forest monitoring, forest genetic monitoring, forest genetic diversity, silviculture
Objavljeno v DiRROS: 20.02.2020; Ogledov: 2028; Prenosov: 1281
.pdf Celotno besedilo (766,78 KB)
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107.
Root-associated fungal communities from two phenologically contrasting Silver Fir (Abies alba Mill.) groups of trees
Tina Unuk Nahberger, Tijana Martinović, Domen Finžgar, Nataša Šibanc, Tine Grebenc, Hojka Kraigher, 2019, izvirni znanstveni članek

Povzetek: Root-associated fungal communities are important components in ecosystem processes, impacting plant growth and vigor by influencing the quality, direction, and flow of nutrients and water between plants and fungi. Linkages of plant phenological characteristics with belowground root-associated fungal communities have rarely been investigated, and thus our aim was to search for an interplay between contrasting phenology of host ectomycorrhizal trees from the same location and root-associated fungal communities (ectomycorrhizal, endophytic, saprotrophic and pathogenic rootassociated fungi) in young and in adult silver fir trees. The study was performed in a managed silver fir forest site. Twenty-four soil samples collected under two phenologically contrasting silver fir groups were analyzed for differences in rootassociated fungal communities using Illumina sequencing of a total root-associated fungal community. Significant differences in beta diversity and in mean alpha diversity were confirmed for overall community of ectomycorrhizal root-associated fungi, whereas for ecologically different non-ectomycorrhizal root-associated fungal communities the differences were significant only for beta diversity and not for mean alpha diversity. At genus level root-associated fungal communities differed significantly between early and late flushing young and adult silver fir trees. We discuss the interactions through which the phenology of host plants either drives or is driven by the root-associated fungal communities in conditions of a sustainably co-naturally managed silver fir forest.
Ključne besede: host phenology, stand age, root-associated fungi, silver fir, fungal community
Objavljeno v DiRROS: 20.02.2020; Ogledov: 1976; Prenosov: 1393
.docx Celotno besedilo (663,43 KB)
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108.
Different belowground responses to elevated ozone and soil water deficit in three European oak species (Quercus ilex, Q. pubescens and Q. robur)
Tanja Mrak, Ines Štraus, Tine Grebenc, Jožica Gričar, Yasutomo Hoshika, Giulia Carriero, Elena Paoletti, Hojka Kraigher, 2019, izvirni znanstveni članek

Povzetek: 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 traits; therefore the combined analysis of root traits is necessary to obtain a complete picture of belowground responses.
Ključne besede: ozone, drought, fine roots, ectomycorrhiza, anatomy, morphology, plants
Objavljeno v DiRROS: 20.02.2020; Ogledov: 1991; Prenosov: 1300
.pdf Celotno besedilo (1,03 MB)
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109.
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Gozd in podnebne spremembe : povzetki referatov znanstvenega srečanja Gozd in les, Ljubljana, 28. novembra 2019
2019, druge monografije in druga zaključena dela

Ključne besede: agrometeorologija
Objavljeno v DiRROS: 04.12.2019; Ogledov: 3221; Prenosov: 1621
.pdf Celotno besedilo (2,75 MB)
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