20.500.12556/RUL-172884 Ksilogeneza in gostotna variacija znotraj branik lesa navadne ameriške duglazije in navadne smreke v Jabljah v letu 2024 Xylogenesis and density fluctuations assessment within tree rings of Douglas-fir and Norway spruce in Jablje in 2024 S pomočjo orodja Trephor smo na izbranem rastišču v Jabljah v Sloveniji v letu 2024 odvzeli mikroizvrtke iz debel dreves navadne smreke (Picea abies) in navadne ameriške duglazije (Pseudotsuga menziesii). Vzorčili smo v rednih časovnih presledkih od aprila (DOY 96) do oktobra (DOY 299) in pripravili mikroskopske preparate, ki so vsebovali floem, kambij in les. Vzorce smo analizirali s svetlobnim mikroskopom in ustrezno programsko opremo. Spremljali smo širino kambijeve cone, postkambijskih celic, fazo tvorjenja sekundarne celične stene, odrasle celice in nekolobirani floem. Pri duglaziji se je kambijeva aktivnost začela prej (DOY 110) kot pri smreki (DOY 127) in je trajala dlje (duglazija: DOY 285, smreka: DOY 264). Povprečna širina kambijeve cone je bila pri duglaziji večja (~172 µm) kot pri smreki (~76 µm). Duglazija je imela na koncu rastne sezone večji prirastek (2317 µm) kot smreka (1395 µm) in večji delež ranega lesa. V letu 2024 pri analiziranih vrstah ni bilo opažene nobene gostotne variacije znotraj branik, kar kaže na stabilne rastne razmere. Gostotne variacije in dvojne branike so bile zaznane pri smreki leta 2023, kar odraža večjo občutljivost na podnebne ekstreme te vrste. Duglazija je kazala bolj enotno zgradbo lesa, kar potrjuje njeno večjo plastičnost, stabilnost rasti in odpornost na podnebne ekstreme, kar so ključne lastnosti za prilagajanje gozdov v prihodnje. Using the Trephor tool, we collected microcores from the stems of Norway spruce (Picea abies) and coast Douglas-fir (Pseudotsuga menziesii) trees at a selected site in Jablje, Slovenia, in 2024. Sampling of microcores was carried out every two weeks from April (DOY 96) to October (DOY 299) and permanent microscope slides containing phloem, cambium and xylem were prepared. The samples were analysed using a light microscope and software. We monitored the width of the cambial zone, postcambial cells, the width of the tissue in the stage of secondary wall formation, mature cells and non-collapsed phloem. In Douglas-fir, cambial activity started earlier (DOY 110) than in spruce (DOY 127) and lasted longer (Douglas-fir: DOY 285, spruce: DOY 264). The average width of the cambial zone was greater in Douglas-fir (~172 µm) than in spruce (~76 µm). At the end of the growing season, Douglas-fir also showed a higher increment (2317 µm) compared to spruce (1395 µm) and a larger proportion of earlywood. No intra-annual density fluctuations (IADFs) were observed in the analysed species for the year 2024, indicating stable growth conditions. Such fluctuations were found only in the spruce tree ring for the year 2023. However, IADFs and double rings were present in spruce in 2023, reflecting higher sensitivity to climatic extremes. Douglas-fir showed a more uniform wood structure and higher density, confirming its greater plasticity, growth stability, and resistance to climatic extremes, which are key traits for future forest adaptation. Ksilogeneza kambij ksilem floem smreka Picea abies duglazija Pseudotsuga menziesii Xylogenesis cambium xylem phloem spruce Picea abies Douglas-fir Pseudotsuga menziesii true false false [A. Zajc] Slovenski jezik Angleški jezik Magistrsko delo/naloga 2025-09-12 07:16:52 2025-09-12 07:16:57 2025-10-27 03:34:16 0000-00-00 00:00:00 2025 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 630*811.29 263637 248276995 50928.pdf 50928.pdf 1 E13C0C9EE8FAC094B33193E71DC9B454 70a89add41cd50aae075e1aca73c9d5a4a17a697e2bd945ed1761e9c1005cfcc 8c39165a-8f97-11f0-9328-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=217018 Biotehniška fakulteta 0 0 0