Microshoots of four hazelnut genotypes grown in vitro on Nas and Read medium (NRM) containing various combinations of CuSO4 • 5H2O and myo-inositol were successfully rooted and acclimatized ex vitro without any need of in vitro hardening treatments. Dipping of shoot bases in 1000 ppm indole-3-butyric acid (IBA) solution for 5 or 10 seconds followed by placement of shoots in plant growth regulator free NRM gave rise to formation of roots as early as 8 days. Shoots treated for 5 and 10 seconds rooted similarly, and depending on genotype, 88% to 98% rooting was observed within 15 days after treatment with IBA. Ex vitro survival of shoots three months after in vitro-root induction was 73% when shoots were treated with IBA for 5 seconds and 66% when shoots were treated for 10 seconds. The highest ex vitro survival rate (97%) 3 months after root induction was observed when shoots were treated with IBA solution for 10 seconds, and then cultured directly in peat pellets. Shoots developed good roots, and grew up to 70 cm in height 3 months after root induction. The potential use of rooting and acclimatization protocol for commercial micropropagation of hazelnut is presented.
Mehmet Nuri Nas and Paul E. Read
Martín Mata-Rosas and Víctor M. Salazar-Rojas
heights ( P = 0.0012), and these were slightly greater than those developed in MS, ranging from 1.8 to 3 cm ( Fig. 1C ). Ex vitro survival. Plantlets of M. tuxtlensis obtained from the KCm treatments did not survive after outplanting; in
Martín Mata-Rosas, Rosario Julieta Baltazar-García, and Victor Manuel Chávez-Avila
treatments and 37.4% in KCm treatments. Ex vitro development. The ex vitro survival of the plantlets was unaffected by the type of culture media or by the type of soil. All plantlets survived, except in three treatments in which the fraction of plants that
Hope Jones and Chieri Kubota
In vitro culture of orchid plantlets within conventional photomixotrophic micropropagation (PMM) systems (sucrose containing media in a non-enriched CO2 environment) often induces vigorous growth and multiplication. However, transition to ex vitro conditions frequently results in significant plantlet loss during the acclimatization process. Recent studies investigating micropropagation within photoautotrophic (PAM) systems (sucrose-free media in enriched CO2 conditions) have demonstrated improved plantlet survival during the acclimatization period due to greater root growth and stomata adaptation. Laelia purpurata var. alba, an orchid with many endangered relatives, was chosen as a model orchid species to investigate if plantlet culture within PAM in vitro systems has the potential to improve propagation success and ex vitro survival of endangered Laelia species. Protocorm-like bodies with developed two fully extended leaves were transferred into PMM (photosynthetic photon flux 50 μmol·m-2·s-1 under non-enriched CO2 conditions) and PAM (photosynthetic photon flux 150 μmol·m-2·s-1, CO2 level enriched to 1500 μmol·mol-1) systems. After 6 weeks, plantlet rooting within the PMM system was variable and inconsistent, while all PAM plantlets produced healthy robust root systems. Average fresh weights and percent shoot development were not significantly different between treatments. Induction of improved root growth by PAM systems may improve orchid plantlet survival rates during acclimatization and advance our ability to increase endangered orchid populations.
Meijun Zhang, Duanduan Zhao, Zengqiang Ma, Xuedong Li, and Yulan Xiao
Momordica grosvenori plantlets were cultured in vitro for 26 d on sucrose- and hormone-free Murashige and Skoog (MS) medium with four levels of photosynthetic photon flux density (PPFD), namely 25, 50, 100, or 200 μmol·m−2·s−1, and a CO2 concentration of 1000 μmol·mol−1 in the culture room [i.e., photoautotrophic micropropagation (PA) treatments]. The control treatment was a photomixotrophic culture using MS medium containing sucrose and NAA with a CO2 concentration of 400 μmol·mol−1 in the culture room and a PPFD of 25 μmol·m−2·s−1. Based on the results, a second experiment was conducted to investigate the effects of α-naphthaleneacetic acid (NAA) and sucrose on callus formation. For this, plantlets were grown in the absence and presence of either NAA or sucrose. Compared with the control, the PA plantlet had a well-developed rooting system, better shoot, greater chlorophyll content, and higher electron transport rate and the ex vitro survival percentage was increased by 31%. Both sucrose and NAA stimulated callus formation on the shoot bases of control plantlets, whereas calluses did not form on the plantlets grown in sucrose- and hormone-free medium. The stronger light intensities increased the fresh and dry weight of plantlets. A PPFD of 100 μmol·m−2·s−1 was more suitable for the growth of M. grosvenori plantlets. Therefore, photoautotrophic plantlets grown at high light intensities would be better suited to the intense irradiance found in sunlight.
Carmen Valero Aracama*, Michael E. Kane, Nancy L. Philman, and Sandra B. Wilson
A sea oats (Uniola paniculata L.) micropropagation protocol was previously developed for 28 genotypes that favored multiplication and rooting of shoots in vitro. However, microcutting size, morphology, and acclimatization ex vitro varied considerably among genotypes. In the present study we evaluated the effect of Stage III duration on in vitro morphology, biomass production, and ex vitro survivability of easy-(EK 16-3) and difficult-to-acclimatize (EK 11-1) sea oats genotypes. After 3, 6, and 9 weeks at Stage III, survivability of microcuttings was 85%, 96% and 98% for EK 16-3, and 2%, 27% and 40% for EK 11-1, respectively. After 9 weeks Stage III, EK 16-3 microcuttings had higher shoot dry weights but lower root dry weights than in EK 11-1. Moreover, roots in EK 11-1 were fewer but longer than in EK 16-3. Leaf production was similar in both genotypes. However, leaf elongation was significantly inhibited in EK 11-1, in which 95% of the leaves were ≤ 15 mm long in contrast with EK 16-3, with 50% leaves ≥ 16 mm long after 9 weeks Stage III. Light microscopy examinations showed anatomical similarities between EK 16-3 in vitro leaves and mature ex vitro leaves. Conversely, short in vitro leaves of EK 11-1 exhibited mesophyll disruption and reduced cuticle development. Conceivably, the short leaves had limited photosynthetic competency, thereby reducing ex vitro survival of rooted EK 11-1 microcuttings.
Carmen Valero Aracama, Michael E. Kane, Sandra B. Wilson, and Nancy L. Philman
, Marysville, OH) prepared with the same source of water as used for watering. Effect of Stage II duration on in vitro multiplication and rooting and ex vitro survival. Plantlets from EK 11-1 and EK 16-3 produced using the protocol described previously
Richard J. Henny, James R. Holm, Jianjun Chen, and Michelle Scheiber
). Colchicine concentrations at 500 mg·L −1 or 1000 mg·L −1 significantly reduced in vitro survival compared with 250 mg·L −1 . Similarly, colchicine reduced ex vitro survival at all treatment rates compared with untreated plants. Although the significance of
Marija Perić, Slavica Dmitrović, Suzana Živković, Biljana Filipović, Marijana Skorić, Ana Simonović, and Slađana Todorović
the critical step for ex vitro survival and preservation of this endangered species has been efficiently overcome. The acclimatized plants were normal without any morphological abnormalities or variations ( Fig. 1H ). Supplementation of sugars to
Aish Muhammad, Hamid Rashid, Iqbal Hussain, and S.M. Saqlan Naqvi
Bhagyalakshmi, N.S. Singh, N.S. 1995 Role of liquid versus agar-gelled media in mass propagation and ex vitro survival in bananas Plant Cell. Tiss. Org. Cult. 41 71 73 Blakesly, D. 1991 Uptake and metabolism of 6