111. Učinek ultravijoličnega sevanja na smreko (Picea abies (L.) Karst) in posledice za gorski gozdni ekosistemTadeja Trošt Sedej, 2005, original scientific article Abstract: Rastline, ki uspevajo v gorah, so pogosto izpostavljene stresnim razmeram, predvsem povečani jakosti sevanja UV-B, skrajnim temperaturnim razmeram ter pomanjkanju vode in hranil. Odziv smreke na okoljske razmere je kompleksen. Pri enoletnih iglicah v visokogorju smo izmerili manjšo fotokemično učinkovitost in vsebnost klorofilov, kar kaže na občutljivost mladih iglic, kjer zaščitni mehanizmi še niso dokončno razviti. Pri starejših iglicah razlika ni bila več statistično značilna, zato sklepamo, da se poškodbe v drugem in tretjem letu preprečijo ali popravijo. Pri dveletnih iglicah smreke z visokogorskega rastišča je bil dihalni potencial značilno manjši in vsebnostUV-B absorbirajočih snovi značilno večja, kar pojasnjujemo s tem, da so dveletne iglice z visokogorskega rastišča med tremi starostnimi razredi najbolj odporne proti UV-B sevanju. Iz rezultatov sicer ne moremo sklepati, v kolikšni meri je k odzivu rastline prispeval posamezni stresni dejavnik, vendar lahko trdimo, da je smreka razmeroma dobro prilagojena na velike jakosti UV-B sevanja in stresne razmere, kakršne vladajo v visokogorju.
Keywords: smreka, Picea abies, drevesa, UV-B sevanje, fotokemična učinkovitost, ETS, UV-B absorbirajoče snovi, vsebnost klorofila, višinski gradient, visokogorsko rastišče, stres
Published in DiRROS: 12.07.2017; Views: 4588; Downloads: 1839
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112. Sezonska dinamika ksilogeneze in floemogeneze pri navadni jelki (Abies alba Mill.)Jožica Gričar, Primož Oven, Katarina Čufar, 2005, original scientific article Abstract: Preučili smo dinamiko nastajanja ksilemskega in floemskega letnega prirastnegaplašča oz. branike pri navadni jelki (Abies alba) v rastni sezoni 2003. Vzorce floema, kambija in ksilema smo vsak teden vzeli iz dveh navideznozdravih odraslih jelk. Raziskave s svetlobnim mikroskopom so pokazale, da se je na floemski strani začela diferenciacija enega do dveh slojev floemskih derivatov še pred začetkom kambijeve aktivnosti. Kambijeva delitvena aktivnost se je začela hkrati na ksilemski in floemski strani v začetku maja. Kambijeva aktivnost se je zaključila konec avgusta. Diferenciacija terminalnih traheid kasnega lesa je potekala do konca oktobra, floemskih celic pa do konca septembra. Število celic, nastalih na ksilemski strani, je bilo večje kot na floemski. Zdi se, da je bila po obodu drevesa širina ksilemske branike bolj variabilna od floemske.
Keywords: navadna jelka, Abies alba Mill., kambij, ksilem, floem, traheide, sitaste celice, diferenciacija
Published in DiRROS: 12.07.2017; Views: 4308; Downloads: 1788
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113. Genetski vidik naravne obnove smrekovega sestoja na nastali raziskovalni ploskvi Šijec na PokljukiGregor Božič, 2005, original scientific article Abstract: Namen raziskave je bil preveriti sposobnost naravnega obnavljanja genetskega vira Picea abies (L.) Karst. na objektu stalne raziskovalne ploskve Šijec na Pokljuki, Slovenija. Genetsko strukturo zrelega sestoja smreke in genetsko strukturo naravnega mladja v razlino velikih pomladitvenih jedrih smo preuili z elektroforetsko analizo 15 polimorfnih izoencimskih genskih lokusov desetih encimskih sistemov (GDH, F-EST, GOT, IDH, LAP, MDH, PGI, PGM, SKDH, 6-PGDH). Pod doloenimi pogoji je bila genetska struktura 101 dreves naravnega pomladka in 64 dreves sestoja, iz katerega je nastal, popolnoma primerljiva. Obnova smrekovega sestoja z naravnim pomlajevanjem zagotavlja trajno ohranjanje genskega vira smreke in je v primeru vejih pomladitvenih jeder tudi zagotoviloza neprekinjeno ohranjanje njegove prilagoditvene sposobnosti.
Keywords: Picea abies (L.) Karst., naravno pomlajevanje, genetska struktura, izoencimi, ohranjanje gozdnih genskih virov, genski viri
Published in DiRROS: 12.07.2017; Views: 4353; Downloads: 1911
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114. Odziv kambija navadne smreke (Picea abies) na ogrevanje in hlajenje deblaJožica Gričar, Martin Zupančič, Katarina Čufar, Primož Oven, 2004, original scientific article Abstract: Proučili smo vpliv eksperimentalnega ogrevanja in hlajenja dela debla navadne smreke (Picea abies) na kambijevo aktivnost in celično diferenciacijo. Poskusasta potekala 30 dni; ogrevanje od 29.3.2004 do 3.5.2004, hlajenje pa od14.6.2004 do 20.7.2004. Vzorce floema, kambija in ksilema smo iz dreves odvzeli vsakih 10 dni, pripravili prečne prereze tkiv in preparate opazovali ssvetlobnim mikroskopom. Lokalno ogrevanje je po 10 dneh induciralo delitveno aktivnost kambija na floemsko stran, po 20 dneh pa tudi na ksilemsko. Po 30 dneh je pri ogrevanem vzorcu nastalo do 15 celic ranega lesa. V tem času se jeredna delitvena aktivnost kambija pri kontrolnem drevesu šele začela. Odziv kambija na hlajenje debla je bil manj izrazit. Anatomskih razlik med kontrolnim in hlajenim vzorcem po 10 in 20 dneh ni bilo. Po 30 dneh je pri hlajenem vzorcu začel nastajati kasni les, pri kontrolnem drevesu pa šele prehodni rani-kasni les. S poskusom smo demonstrirali, da je mogoče pri smrekiz umetnim ogrevanjem in hlajenjem debla vplivati na ksilo- in floemogenezo.
Keywords: navadna smreka, Picea abies, kambij, celična diferenciacija, ksilem, floem, ogrevanje, hlajenje, svetlobna mikroskopija, Norway spruce, cambium, cell differentiation, xylem, phloem, heating, cooling, light microscopy
Published in DiRROS: 12.07.2017; Views: 4578; Downloads: 2022
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115. Analysis of the influece of ungulates on the regeneration of Dinaric fir-beech forests in the research site Trnovec in the Kočevje forest managementregionKristjan Jarni, Dušan Robič, Andrej Bončina, 2004, original scientific article Abstract: In the period 1970-2000, 152 fenced-in areas were built in the Kočevje Forest Management Region with an aim to protect tree seedlings and saplings from ungulatesć activity and to monitor the influence of roe and red deer on natural regeneration. The average surface area of fenced areas is 0.71 ha. Using the pair comparison technique (fenced vs. unfenced areas), the structureand the composition of the natural regeneration of tree species as well as complete shrub and herb vegetation were analysed in the research site Trnovec. Furthermore, the vegetation was investigated using the Braun-Blanquetmethod. The research results show significant differences between fenced and unfenced areas, both in tree species composition and in theheight structure of the sapling community. In fenced areas the total numberof saplings taller than 50 cm is higher and an increase is also evident in the number of saplings of silver fir Abies alba, sycamore Acer pseudoplatanus, elm Ulmus glabra and other minor tree species. There are also significant differences in species composition and in the abundance of plant species in the herb layer. The results show that natural regeneration of Dinaric fir-beech forests is successful, provided the influence of ungulates is excluded.
Keywords: natural forest regeneration, Fagus sylvatica, roe deer, fir-beech forest, Abies alba, fenced area, seedling browsing, Kočevje forest region, research site Trnovec
Published in DiRROS: 12.07.2017; Views: 4500; Downloads: 2016
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116. Genetska diferenciacija avtohtonih populacij smreke (Picea abies (L.) Karst.) v Sloveniji, ugotovljena z analizo izoencimovGregor Božič, Monika Konnert, Mitja Zupančič, Hojka Kraigher, Ivan Kreft, 2003, original scientific article Abstract: Raziskava obravnava genetsko diferenciacijo 22 populacij smreke (Picea abies (L.) Karst.) z njenih naravnih rastišč v Sloveniji in 4 na Hrvaškem z analizo izoencimskih genskih označevalcev. Razlike med populacijami smo ocenili z genetskimi razdaljami po Gregoriusu (1974) za 15 polimorfnih genskih lokusov. Vrednosti genetskih razdalj se gibljejo med 0,021 in 0,073 (v Sloveniji do 0,063). Izoencimska genetska diferenciranost smreke je razmeroma majhna. Rezultati hierarhične klasifikacije nakazujejo geografsko odvisno združevanjepopulacij v dve skupini: alpsko skupino s Trnovskim gozdom in osrednje dinarsko skupino. Skupini se na območju Snežnika tudi prekrivata.
Keywords: Picea abies (L.) Karst, izoencimi, genetska diferenciacija, varstvo gozdnih genskih virov, Slovenija, Hrvaška
Published in DiRROS: 12.07.2017; Views: 4343; Downloads: 2039
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117. Differentiation of last formed tracheids in wood of silver firs (Abies alba) having various cambial productivityJožica Gričar, Aleš Straže, Katarina Čufar, 2003, original scientific article Abstract: To examine the state of differentiation of the last tracheids formed in wood and the duration of cambial activity, samples of wood and cambium were taken from mature silver fir (Abies alba) trees having various cambial productivity.Semi-thin cross-sections of wood sampled in July and October, 1999, were stained with toluidine blue and observed under a light microscope. In July, three different phases of current annual xylem growth ring formation were found, as a result of various cambial tree productivity. In October, the cell divisions in the cambium were completed in all investigated trees, while the process of differentiation was not entirely completed in trees with a more productive cambium. The number of undifferentiated tracheids was higher in trees having a more productive cambium. In these trees, the cambial activity and the differentiation ended later. In declining trees, the number of cells produced by the cambium was lower and the duration of cambial activity was shorter.
Keywords: navadna jelka, Abies alba, les, traheide, kambijeva aktivnost, diferenciacija, wood, silver fir, tracheids, cambial activity, differentiation
Published in DiRROS: 12.07.2017; Views: 4365; Downloads: 1975
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118. Light response of Fagus sylvatica L. and Abies alba Mill. in different categories of forest edge - vertical abundance in two silvicultural systemsMatjaž Čater, Andrej Kobler, 2017, original scientific article Abstract: In managed Dinaric montane fir (Abies alba Mill.) and European beech (Fagus sylvatica L.) forests, the light response of young beech and fir in gap microsites was studied during three consecutive growing periods (2009, 2010, and 2011) under controlled environmental conditions in stands of single-tree and irregular shelterwood silvicultural system. According to maximal quantum yield, the different response between species in microsite light categories was evidenced for silver fir on microsites with predominating diffuse light and for beech on microsites with predominating direct light, respectively. Abundance and change of share in microsite light categories was compared over different elevation belts on comparable sites between two silvicultural systems. The share of forest edge area was bigger in the irregular shelterwood system. Change in width of forest edge (20, 30 and 40 m) did not affect the proportion and share of the microsite in both regions of different silvicultural system. Separation of microsite areas between both silvicultural systems, evident in lower elevation belts was not evident in the most conflict and highest elevation zone, while the absolute values of all categories above 700 m in both systems were almost identical, indicating the same, small-scale irregular shelterwood system, known also as the freestyle silvicultural approach.
Keywords: Fagus sylvatica, Abies alba, Dinaric silver fir and beech forests, Dinaric forests, forest edge, silviculture, selective system, irregular shelterwood system
Published in DiRROS: 12.07.2017; Views: 2966; Downloads: 1213
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