20.500.12556/RUL-64144 Dvokrpi ginko (Ginkgo biloba L.) in njegov les Maidenhair tree (Ginkgo biloba L.) and its wood Ginko je edina preživela vrsta rodu, ki se je komajda kaj spremenil v zadnjih 150 milijonih let in je edini živeči predstavnik debla Ginkgophyta ('živi fosil'). Ginko je dvodomna golosemenka, vendar ne tvori storžev. Videti je kot dvokaličniško drevo razen listov, ki imajo dihotomno venacijo. Semenske zasnove so 'gole'. Izjemno mesto med semenkami je tudi v tem, da se oploditev izvede z bičkastimi spermiji. Les je koniferoiden. Traheje manjkajo. Anatomskose zlahka loei od iglavcev po velikih celicah v pramenih aksialnega parenhima, ki vsebujejo kristalne druze. Traheide pri ginku niso oglate kot pri večini konifer, temveč so nekoliko zaobljene. Zato se pojavljajo medcelieni prostori. Stene traheid kasnega lesa niso odebeljene. Les z nizko gostoto je homogen, mehak, svetlorjav in ima svilnat lesk. Je brez črnjave. Poranitvi se pojavi rjav diskoloriran les. Ginkgo biloba (maidenhair tree) is the sole survivor of a genus that has changed little for more than 150 million years and is the only member of the phylum Ginkgophyta (Êliving fossilĚ). Ginkgo is dioecious and gimnospermous, but cones are not produced. It looks very much like a dicot tree except that its leaves have dichotomous veins and it bears naked ovules. Its unique feature amongst the seed plants is that fertilization is achieved by motile sperm. Its coniferoid wood lacks vessels. Anatomically it is readily distinguished from conifers bysingle large cells in the axial parenchyma strands containing druses. Ginkgo lack the regulary close-fitting rectangular tracheids characteristically found in most conifers. The tracheids are slightly rounded consequently giving rise to intercellular spaces. Latewood tracheids are not thickened. The low-density wood is homogeneous, soft, light brown and has silky sheen. Heartwood is lacking. After wounding dark brown discoloured wood form. dvokrpi ginko (Ginkgo biloba L.) evolucija raba les ksilotomija Maidenhair tree (Ginkgo biloba L.) evolution wood usage xylotomy true false false Zveza društev inženirjev in tehnikov gozdarstva in lesarstva Slovenije Slovenski jezik Slovenski jezik Delo ni kategorizirano 2015-07-10 19:48:04 2015-07-10 19:48:04 2022-08-01 12:41:52 0000-00-00 00:00:00 1999 0 0 Str. 397-402 št. 12 Let. 51 1999 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 630*174.6 (Ginkgo biloba L.) 0024-1067 547465 13940224 http://www.dlib.si/details/URN:NBN:SI:DOC-XCEG86V6 1 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=64155 RAZ_Torelli_Niko_1999.pdf RAZ_Torelli_Niko_1999.pdf 1 6E268D5974C229B3C09A1AE286461637 5f4fb9a89fbed97e05686d44304ce455094cb1474671f8d9be801a8043371754 29119cca-5dbe-11ec-abdb-00155dcfd717 20.500.12556/rul/f7d5b75f-5122-4134-9f6a-02e29e08792a https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=152160 Biotehniška fakulteta Les 0 0 0