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Povzetek: It is unclear how the anticipated climate change will affect the timing of phenology of different tree organs/tissues and thus the whole-tree functioning. We examined the timing of leaf phenology and secondary growth in three coexisting deciduous tree species (Quercus pubescens Willd., Fraxinus ornus L. and Ostrya carpinifolia Scop) from a sub-Mediterranean region in 2019. In addition, we investigated the relationship between leaf and cambial phenology and the onset of the potential functioning of initial conduits, as determined by the completed differentiation process (vessels) or final size (sieve tubes). For this purpose, leaf development was monitored and the microcores of cambium and the youngest phloem and xylem increments were repeatedly collected at 7-10-day intervals during the growing season. The results revealed differences in the timing of leaf development and seasonal radial growth patterns in spring among the studied tree species, depending on wood porosity. We found that cambial cell production started in all cases in the first half of March. However, in ring-porous Q. pubescens and F. ornus, radial growth in the stem occurred more than a month before buds were swollen, whereas in diffuse-porous O. carpinifolia, these two events were detected at almost the same time. The end of cambial cell production occurred earliest in F. ornus (mid-July) and two weeks later also in the other two species. The widest initial earlywood vessels and early phloem sieve tubes were found in Q. pubescens, the narrowest initial earlywood vessels in O. carpinifolia and the narrowest early phloem sieve tubes in F. ornus. This indicates differences in the e%ciency of conducting systems among the studied species. This novel approach of studying phloem phenology and anatomy in relation to leaf and xylem development contributes to a better understanding of how different tree species adapt their structure of secondary vascular tissues in response to environmental change.
Ključne besede: Quercus pubescens, Fraxinus ornus, Ostrya carpinifolia, earlywood, early phloem, vessel, sieve tube, radial growth
Objavljeno v DiRROS: 21.10.2020; Ogledov: 1299; Prenosov: 942
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Povzetek: We explored the inter-individual variability in bud-burst and its potential drivers, in homogeneous mature stands of temperate deciduous trees. Phenological observations of leaves and wood formation were performed weekly from summer 2017 to summer 2018 for pedunculate oak, European beech and silver birch in Belgium. The variability of bud-burst was correlated to previous' year autumn phenology (i.e. the onset of leaf senescence and the cessation of wood formation) and tree size but with important differences among species. In fact, variability of bud-burst was primarily related to onset of leaf senescence, cessation of wood formation and tree height for oak, beech and birch, respectively. The inter-individual variability of onset of leaf senescence was not related to the tree characteristics considered and was much larger than the inter-individual variability in bud-burst. Multispecies multivariate models could explain up to 66% of the bud-burst variability. These findings represent an important advance in our fundamental understanding and modelling of phenology and tree functioning of deciduous tree species.
Ključne besede: leaf unfolding, wood formation, coloration, Pedunculate oak, European beech, Silver birch
Objavljeno v DiRROS: 10.06.2020; Ogledov: 1929; Prenosov: 1130
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Povzetek: Krčenje zalog fosilnih goriv, netrajnostno izkoriščanje naravnih virov in podnebne spremembe so dejavniki, ki pospešujejo prehod v biogospodarstvo. Tovrsten prehod omogočajo tehnologije in novo znanje pretvorbe biomase v različne produkte, med seboj povezane v kaskadnih in (energetsko in snovno) krožnih proizvodnih ciklih. Eno ključnih področij biogospodarstva je področje rabe lesa, ki trenutno prispeva eno tretjino k skupni dodani vrednosti slovenskega biogospodarstva. Glede na stanje v državah s primerljivimi naravnimi in strukturnimi danostmi Slovenija v razvoju biogospodarstva zaostaja. V pričujočem delu smo predstavili generične dejavnike, ki vplivajo na razvoj biogospodarstva ter pripravili pregled stanja slovenskega biogospodarstva na področju rabe lesa. Stanje slovenskega biogospodarstva uvrščamo v širši evropski okvir ter ocenjujemo nadaljnje možnosti razvoja rabe lesa.
Ključne besede: biogospodarstvo, lesna biomasa, obnovljivi viri energije, raba lesa, biorafinerije, kaskadna raba lesa
Objavljeno v DiRROS: 20.12.2019; Ogledov: 2706; Prenosov: 768
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Povzetek: To understand better the adaptation strategies of intra-annual radial growth in Pinus halepensis and Pinus sylvestris to local environmental conditions, we examined the seasonal rhythm of cambial activity and cell differentiation at tissue and cellular levels. Two contrasting sites differing in temperature and amount of precipitation were selected for each species, one typical for their growth and the other represented border climatic conditions, where the two species coexisted. Mature P. halepensis trees from Mediterranean (Spain) and sub-Mediterranean (Slovenia) sites, and P. sylvestris from sub-Mediterranean (Slovenia) and temperate (Slovenia) sites were selected. Repeated sampling was performed throughout the year and samples were prepared for examination with light and transmission electron microscopes. We hypothesized that cambial rhythm in trees growing at the sub-Mediterranean site where the two species co-exist will be similar as at typical sites for their growth. Cambium in P. halepensis at the Mediterranean site was active throughout the year and was never truly dormant, whereas at the sub-Mediterranean site it appeared to be dormant during the winter months. In contrast, cambium in P. sylvestris was clearly dormant at both sub-Mediterranean and temperate sites, although the dormant period seemed to be significantly longer at the temperate site. Thus, the hypothesis was only partly confirmed. Different cambial and cell differentiation rhythms of the two species at the site where both species co-exist and typical sites for their growth indicate their high but different adaptation strategies in terms of adjustment of radial growth to environmental heterogeneity, crucial for long-term tree performance and survival.
Ključne besede: Aleppo pine, Pinus halepensis, Scots pine, Pinus sylvestris, cambium, light microscopy, Mediterranean environment, temporate environment, transmission electron microscopy, xylem
Objavljeno v DiRROS: 12.07.2017; Ogledov: 3229; Prenosov: 1463
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Ključne besede: proizvodne dejavnosti, lesnopredelovalni obrati, industrija, prostorski načrti
Objavljeno v DiRROS: 12.07.2017; Ogledov: 2497; Prenosov: 815
Celotno besedilo (25,97 MB)