Mikroklonsko razmnožavanje divlje trešnje (Prunus avium L.) iz vegetacijskog vrška stabla i izdanka korjenjaka

The effects of different combinations and concentrations of the growth regulators: 6-benzylaminopurine (BA), 6-furfurylaminopurine (KIN), N6- (2-isopentenyl) adenine (2iP), indole-3-butyric acid (IBA), indole-3-acetic acid (IAA) and a-naphthaleneacetic acid (NAA) on axillary shoot multiplication rates for wild cherry (Prunus avium L.) shoot explants were determined. Apical shoot tips and axillary buds from juvenile trees (5-year old) and from root suckers of mature trees (55-year old) were used as initial explants for establishment of multiple shoot cultures. Factorial tests for growth regulator interactions with the two genotypes showed significant differences in shoot multiplication rate with numerous auxin- and cytokinin-amended basal media. For genotype P5, the most effective growth regulator combination was 5.0 mg/L KIN and 1.0 mg/L IAA. Genotype 5/11 responded best to 1.0 mg/L BA and 5.0 mg/L IBA. Both clones multiplied easily in culture, and shoot multiplication of the mature genotype was not inhibited.Istražen je utjecaj različitih kombinacija i koncentracija regulatora rasta: 6-benzilaminopurina (BA), 6-furfurilaminopurina (KIN), n6-(2-izopentenil) adenina (2iP), indol-3-maslačne kiseline (IBA), indol-3-octene kiseline (IAA) i a-naftalenoctene kiseline (NAA) na stopu umnožavanja izdanka divlje trešnje (Primus avium L.). Kao početni eksplantati za postavljanje kulture upotrebljeni su vršni i bočni pupovi mlade biljke stare pet godina (genotip 5/11) i izdanci razvijeni iz korjenjaka stabla starog 55 godina (genotip P5). Uočene su statistički značajne razlike u stopi umnožavanja izdanaka na podlogama s različitim kombinacijama regulatora rasta. Za umnožavanje izdanaka genotipa P5 najbolja je bila podloga s 5,0 mg/L KIN i 1,0 mg/L IAA, dok su se izdanci genotipa 5/11 najbolje umnažali na podlozi s 1,0 mg/L BA. i 5,0 mg/L IBA. Oba klona mogla su se uspješno umnožavati u kulturi, a umnožavanje izdanaka odraslog genotipa nije bilo inhibirano

Time-resolved spectroscopy of multi-excitonic decay in an InAs quantum dot

The multi-excitonic decay process in a single InAs quantum dot is studied through high-resolution time-resolved spectroscopy. A cascaded emission sequence involving three spectral lines is seen that is described well over a wide range of pump powers by a simple model. The measured biexcitonic decay rate is about 1.5 times the single-exciton decay rate. This ratio suggests the presence of selection rules, as well as a significant effect of the Coulomb interaction on the biexcitonic wavefunction.Comment: one typo fixe

Polarization-Correlated Photon Pairs from a Single Quantum Dot

Polarization correlation in a linear basis, but not entanglement, is observed between the biexciton and single-exciton photons emitted by a single InAs quantum dot in a two-photon cascade. The results are well described quantitatively by a probabilistic model that includes two decay paths for a biexciton through a non-degenerate pair of one-exciton states, with the polarization of the emitted photons depending on the decay path. The results show that spin non-degeneracy due to quantum-dot asymmetry is a significant obstacle to the realization of an entangled-photon generation device.Comment: 4 pages, 4 figures, revised discussio

Sub-microsecond correlations in photoluminescence from InAs quantum dots

Photon correlation measurements reveal memory effects in the optical emission of single InAs quantum dots with timescales from 10 to 800 ns. With above-band optical excitation, a long-timescale negative correlation (antibunching) is observed, while with quasi-resonant excitation, a positive correlation (blinking) is observed. A simple model based on long-lived charged states is presented that approximately explains the observed behavior, providing insight into the excitation process. Such memory effects can limit the internal efficiency of light emitters based on single quantum dots, and could also be problematic for proposed quantum-computation schemes.Comment: 8 pages, 8 figure

Mikroklonsko razmnožavanje divlje trešnje (Prunus avium L.) iz vegetacijskog vrška stabla i izdanka korjenjaka

The effects of different combinations and concentrations of the growth regulators: 6-benzylaminopurine (BA), 6-furfurylaminopurine (KIN), N6- (2-isopentenyl) adenine (2iP), indole-3-butyric acid (IBA), indole-3-acetic acid (IAA) and a-naphthaleneacetic acid (NAA) on axillary shoot multiplication rates for wild cherry (Prunus avium L.) shoot explants were determined. Apical shoot tips and axillary buds from juvenile trees (5-year old) and from root suckers of mature trees (55-year old) were used as initial explants for establishment of multiple shoot cultures. Factorial tests for growth regulator interactions with the two genotypes showed significant differences in shoot multiplication rate with numerous auxin- and cytokinin-amended basal media. For genotype P5, the most effective growth regulator combination was 5.0 mg/L KIN and 1.0 mg/L IAA. Genotype 5/11 responded best to 1.0 mg/L BA and 5.0 mg/L IBA. Both clones multiplied easily in culture, and shoot multiplication of the mature genotype was not inhibited.Istražen je utjecaj različitih kombinacija i koncentracija regulatora rasta: 6-benzilaminopurina (BA), 6-furfurilaminopurina (KIN), n6-(2-izopentenil) adenina (2iP), indol-3-maslačne kiseline (IBA), indol-3-octene kiseline (IAA) i a-naftalenoctene kiseline (NAA) na stopu umnožavanja izdanka divlje trešnje (Primus avium L.). Kao početni eksplantati za postavljanje kulture upotrebljeni su vršni i bočni pupovi mlade biljke stare pet godina (genotip 5/11) i izdanci razvijeni iz korjenjaka stabla starog 55 godina (genotip P5). Uočene su statistički značajne razlike u stopi umnožavanja izdanaka na podlogama s različitim kombinacijama regulatora rasta. Za umnožavanje izdanaka genotipa P5 najbolja je bila podloga s 5,0 mg/L KIN i 1,0 mg/L IAA, dok su se izdanci genotipa 5/11 najbolje umnažali na podlozi s 1,0 mg/L BA. i 5,0 mg/L IBA. Oba klona mogla su se uspješno umnožavati u kulturi, a umnožavanje izdanaka odraslog genotipa nije bilo inhibirano

Desirable properties of wood for sustainable development in the twenty-first century

International audienceOur objective is to evaluate how a broad and long-range set of needs for sustainable development will influence commercial requirements for wood and desirable wood properties. We emphasize ways forest products and wood properties can contribute to greenhouse gas (GHG) mitigation and provide a vision for sustainable production and use