Slovenian Submediterranean is characterized by two types of bedrock, flysch and carbonate. Soils on carbonate were eroded to a large degree in the past due to human activities, forming a typical stony landscape, Karst. After abandonment of pastures, area was spontaneously encroached by various woody species with dominant pubescent oak (Quercus pubescens Willd.). Pubescent oak is ecologically very important for this area, as it prevents further degradation of shallow soils. Harsh abiotic factors (frequent drought and wildfires) are strongly limiting growth in this area, but on the other hand, ectomycorrhizal fungi may have beneficial effects. To characterize ectomycorrhizal fungal (EMF) communities of pubescent oak on two types of bedrock, soil cores from calcareous and flysch plots were collected from June 2016 till May 2018. From each soil core, ectomycorrhizal morphotypes associated with oak roots were isolated, morpho-anatomically characterized, and sequenced using ITS1/ITS4 markers. Assembled sequences were identified using UNITE database and molecular identification was compared and combined with morpho-anatomical identification. Community composition of EMF was affected by season and bedrock. Calcareous plot was characterized by higher species richness and lower seasonal variability of species richness compared to flysch plot. Maximum of species richness occurred at both types of bedrock at the same time. For the whole period and both plots, around 70 morphotypes of EMF were listed. Significantly higher abundance of Cenococcum geophilum (Gloniaceae, Ascomycota) was recorded for calcareous plot, and Sebacina sp. (Sebacinaceae, Basidiomycota) for flysch plot. The lowest percentage of vital ectomycorrhizal tips was detected in 2017, a year following wildfire.
B.06 Other
COBISS.SI-ID: 5607846Tree growth is intimately linked to the environment, which directly influence physiological processes. Trees continuously adjust their structure to fit the changing environmental conditions. In the processes of radial growth, which encompasses xylogenesis and phloemogenesis, these structural adjustments can be achieved. Therefore, wood and phloem anatomy can represent a good indicator of tree success and performance. Xylem formation has already proven to be influenced by environmental factors, whereas drivers of phloem formation and structure have generally been less investigated. Unlike wood formation, annual formation of phloem is crucial for tree survival as it maintains the translocation pathways for photosynthates from leaves to the tissues where growth and storage occur. In the presentation, various intra-annual patterns of xylem and phloem development of trees from different environments were shown. Cambial rhythm and xylem and phloem anatomy of trees from temperate and (sub)Mediterranean were presented to demonstrate the plasticity of their radial growth, which enables them to respond and adapt to changing environmental conditions. Finally, we discussed how radial growth studies can complement with ecophysiological and dendroecological observations. Understanding how the secondary growth of trees responds to changing environmental conditions contributes to the major scientific challenges related to future tree performance under global climate change.
B.04 Guest lecture
COBISS.SI-ID: 5199014We studied the effect of soil properties, drought and fire events on leaf development, cambial phenology, and xylem and phloem anatomy of Q. pubescens at Podgorski kras. Our results suggest that weather conditions in the driest summer months (July–August) have no major effect on the duration of radial growth, because cambial cell production is generally finished by the end of July/beginning of August, which might be an adaptation of Q. pubescens to local environmental conditions in terms of finishing its radial growth before stressful conditions. Moreover, the comparable age of trees at the two plots but different diameters and heights suggest that soil properties differing in water holding capacity greatly affect the above-ground growth and cell characteristics of Q. pubescens. The dynamics of radial growth contribute most to the differences in the final widths of the annual increments. However, in addition to micro-site environmental conditions, tree and crown sizes are presumed to affect vessel diameter. Furthermore, the exposure of Q. pubescens to fire is traceable in xylem and phloem anatomies in the next growing season. The post-fire structural adjustments of the two vascular tissues are not coordinated; fire causes changes in the conduit properties in the phloem but not in the xylem. This could be explained by their different positions and roles in a tree.
B.06 Other
COBISS.SI-ID: 5388198