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61.
M. von Sivers 《Forstwissenschaftliches Centralblatt》1911,33(3):148-151
Ohne Zusammenfassung 相似文献
62.
M. von Uiblagger 《Forstwissenschaftliches Centralblatt》1904,26(8-9):463-481
Ohne Zusammenfassung 相似文献
63.
64.
von Pechmann 《Forstwissenschaftliches Centralblatt》1932,54(19):645-661
Ohne Zusammenfassung 相似文献
65.
von Pechmann 《Forstwissenschaftliches Centralblatt》1932,54(18):605-622
Ohne Zusammenfassung 相似文献
66.
von Pechmann 《Forstwissenschaftliches Centralblatt》1933,55(19):660-666
Ohne Zusammenfassung 相似文献
67.
Embryogenic tissue of hybrid larch (Larix x marschlinsii Coaz) was multiplied on Medium M (modified MSG medium supplemented with the plant growth regulators (PGRs) 2,4-dichlorophenoxyacetic acid (2,4-D; 9 microM) and N-6-benzyladenine (2.25 microM)). After 1 week, cultures were transferred to either MSG lacking PGRs (Medium C-) or MSG lacking PGRs but supplemented with 1% activated charcoal (Medium C+). Embryos were sampled after 1 week on Medium M, C- or C+. Embryos were analyzed by ELISA for abscisic acid (ABA), abscisic acid-glucose ester, 2,4-D, indole-3-acetic acid (IAA), indole-3-aspartate (IAAsp), zeatin (Z), zeatin riboside (ZR), isopentenyladenine (iP) and isopentenyladenosine (iPA). Transfer of embryos to Medium C+ reduced the embryo concentrations of 2,4-D and iPA, but resulted in elevated concentrations of IAA, IAAsp, ABA, Z, ZR and iP. Charcoal reduced 2,4-D concentrations of embryos by an order of magnitude greater than PGR-free medium alone. Charcoal affected embryo concentrations of five of the eight PGRs quantified. Use of either C+ or C- medium as part of the maturation protocols also affected germination and plantlet establishment of the embryos. A 1-week treatment on Medium C+ positively influenced plantlet establishment and generally reduced variability during both germination and plantlet establishment. 相似文献
68.
Somatic embryos of Norway spruce (Picea abies (L.) Karst.) differentiate from proembryogenic masses (PEMs), which are subject to autodestruction through programmed cell death. In PEMs, somatic embryo formation and activation of programmed cell death are interrelated processes. We sought to determine if activation of programmed cell death in PEMs is caused by genetic aberrations during somatic embryogenesis. Based on the finding that withdrawal of auxin and cytokinin induces programmed cell death in PEMs, 1-week-old cell suspensions were cultured in medium either with or without auxin and cytokinin and then transferred to maturation medium containing abscisic acid. We analyzed the stability of three nuclear simple sequence repeat (SSR) microsatellite markers at successive stages of somatic embryogenesis in two cell lines. There were no mutations at the SSR loci at any of the successive developmental stages from PEMs to cotyledonary embryos, irrespective of whether or not the proliferation medium in which cell suspensions had been cultured contained auxin or cytokinin. The morphologies of plants regenerated from the cultures were similar, although withdrawal of auxin and cytokinin significantly stimulated the yield of both embryos and plants. We conclude, therefore, that the high genetic stability of somatic embryos in Norway spruce is unaffected by the induction of programmed cell death caused by withdrawal of auxin and cytokinin. 相似文献
69.
70.
H. von Pechmann 《European Journal of Forest Research》1971,90(1):224-235
Summary The very quick rise of mining, salt-production, oretrade and metal-industrie caused in the 16. century an enormous need in
wood and charcoal, added to this the consumption of firewood in the cities, the need of wood for glassworks and various woodworkers
and of timber for a raising population. Floats on the rivers were the most important transport means for commerce as well
as for travelling.
The economic structure-changes at the end of the Middle Ages led to a high valuation of the forests as most important raw
material reserves. It showed itself in the effort of the state-authorities to preserve the growingstock; restrict the customary
forest utilizations and to orderly management of the forests against the opposition of the farmers, who stuck to their old
customary rights. The beginning of a forest literatur as well as a great number of forest orders contain progressive instructions
for prevention and care of the forests.
Moreover the new appreciation of nature, plants and trees produced splendid gardens and the first paintings emphasizing landscapes
and forests.
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