., 2000 ). Using plant growth substances such as GA 3 or N-6-benzyladenine (BA) separately at high temperatures failed to induce phalaenopsis to spike or bloom ( Chen et al., 1994 , 1997 ; Kubota et al., 1997 ). However, Chen et al. (1994) injection
Po-Hung Wu and Doris C.N. Chang
high concentration of BA (greater than 88.8 μM BA) on shoot development was observed, suggesting that such a high level of BA is toxic to C. formosanum explants. Table 1. The effects of N 6 -benzyladenine (BA) and thidiazuron (TDZ
Dennis P. Stimart, John C. Mather, and Kenneth R. Schroeder
Expanding shoot tips of Pulmonaria `Roy Davidson' and Pulmonaria saccharata `Margery Fish' were cultured in vitro on a modified Murashige and Skoog medium containing BA to establish proliferating cultures for use in comparing BA concentrations on shoot proliferation and rooting. The optimum level for shoot proliferation was 8.8 μm BA. Greatest rooting was on medium without BA. Genotype and time in culture influenced shoot and root counts. Chemical names used: N6-benzyladenine (BA)
M.L. Arrebola, O. Socorro, A. Barceló-Muñoz, E. Simón-Pérez, and Fernando Pliego-Alfaro
A micropropagation procedure for juvenile and adult savory (Satureja obovata Lag.) explants is described. Pretreatment of the nutlets with gibberellic acid (0.57 mm) did not improve in vitro germination. Optimum shoot proliferation of juvenile and adult material was obtained on medium containing 2.22 μm N6-benzyladenine. Rooting and acclimatization of juvenile shoots were accomplished in vivo, while adult shoots were rooted in vitro after 3 days of exposure to 4.92 μm indole-3-butyric acid followed by subsequent transfer to auxin-free medium. More than 95% survival of adult rooted plants was obtained during the acclimatization phase. Chemical names used: gibberellic acid (GA3); N6-benzyladenine (BA); indole-3-butyric acid (IBA); isopentenyladenine (2iP).
Paula P. Chee
An embryo culture method overcomes the lengthy dormancy requirement of Taxus L. spp. (yew) seeds. When zygotic embryos excised from mature T. brevifolia L. seeds were cultured in darkness for 4 weeks on one of three basal salt media (B5, Litvay, and Murashige and Skoog), radicle emergence and seedling development was highest on B5 basal salt medium. After 1 to 2 weeks on B5 basal salt medium, seedling development of T. brevifolia, T. cuspidata L., T. baccata L., and T. baccata stricta L. ranged from 2% to 36%. BA at 2.25 μm had no effect on radicle emergence; 22.5 μm prevented it. Embryos excised from mature or nearly mature seeds had the highest frequency of radicle emergence and seedling development. Cultured embryos developed seedlings in only 8 to 10 weeks. Chemical name used: N 6-benzyladenine (BA).
Yuexin Wang, Zoran Jeknić, Richard C. Ernst, and Tony H.H. Chen
To improve the efficiency of iris plant regeneration, we tested the influence of several combinations of Kin and NAA in culture media on the induction of morphogenesis and the subsequent development of plantlets. The highest rates of regeneration (67%) were consistently observed in induction media containing 0.5 μm NAA and either 2.5 or 12.5 μm Kin. Developing medium containing 1.25 μm BA was optimal for high regeneration rates and a high percentage of plantlets simultaneously developing shoots and roots. Rooted plantlets were easily acclimatized and transplanted to various soil mixtures, then grown in the greenhouse. Under optimal conditions as many as 8000 plantlets could be regenerated from 1 g of cells in ≈4 months. Chemical names used: kinetin (Kin); 1-naphthaleneacetic acid (NAA); N6-benzyladenine (BA).
Dennis P. Stimart and John C. Mather
Cotyledons from developing 6- to 8-week-old embryos of Liatris spicata (L.) Willd. (blazing star) were cultured on Murashige and Skoog medium containing 0, 0.4, 4.4, or 44.4 μm BA or 0, 0.2, 2.2, or 22.2 μm TDZ to induce adventitious shoot formation. The highest percentage of cotyledons forming the most shoots was on medium containing 2.2 μm TDZ. Cotyledon-derived callus cultured on medium containing 4.4 μm BA formed ≈16 times more adventitious shoots than on 2.2 μm TDZ. Adventitious shoots derived from cotyledons or callus produced roots when placed on MS medium containing 5.0 μm IBA. Regenerated plants that flowered in the field appeared homogeneous. Chemical names used: N6-benzyladenine (BA), thidiazuron (TDZ), indole-3-butyric acid (IBA).
Xiaoling Yu and Barbara M. Reed
A micropropagation system was developed for hazelnut cultivars. Grafted greenhouse-grown plants produced many more viable explants than upper branches of mature field-grown trees. Shoots from grafted greenhouse-grown plants collected March through July and suckers of mature field-grown trees collected in July produced the most growing explants (46% to 80%). Three- to five-fold multiplication was obtained after 4 weeks of culture on NCGR-COR medium supplemented with 6.7 μm BA and 0.04 μm IBA. Roots were produced on 64% to 100% of shoots grown on half-strength NCGR-COR mineral salts and 4.9 μm IBA for 4 weeks. Ex vitro rooting by a brief dip in 1 or 5 mm IBA was equally successful. Transplant survival was 78% to 100%. Chemical names used: N 6-benzyladenine (BA); indole-3-butyric acid (IBA).
Lunique Estime, Marie O'Shea, Michael Borst, Jennifer Gerrity, and Shih-Long Liao
Typha latifolia L. (broadleaf cattail) callus was initiated from leaf sections, as well as from pistillate and staminate spikes. Two basal media in combination with three growth regulator regimes were tested for their capacity to induce callus from the explants. Pistillate spikes maintained in the dark on B5 medium supplemented with 5 mg·L-1 dicamba and 1 mg·L-1 BA produced the fastest growing cell line compared to other explants and media combinations. A growth curve in suspension culture was generated for this cell line on B5 medium. The mass of the callus increased by 150% by the end of the growth curve. Upon transfer of the callus to MS medium without growth regulators but with 3% sucrose and 3% phytagel, plants could be regenerated from 22% of the cultures. Chemical names used: 3,6-dichloro-2-methoxybenzoic acid (dicamba); N 6-benzyladenine (BA).
Masanori Kadota, Dong-Sheng Han, and Yoshiji Niimi
Anthers of six apple [Malus ×domestica (L.) Borkh.], three Japanese pear (Pyrus pyrifolia N.) and two European pear (Pyrus communis L.) scion cultivars were cultured. Callus formation occurred from anthers of all cultivars and androgenic embryogenesis was observed from all except P. pyrifolia `Kosui' and P. communis `La France'. Regeneration of adventitious shoots from anther-derived embryos was shown from all apple cultivars and P. pyrifolia `Shinko'. Many of these shoots did not grow or died on half-strength Murashige and Skoog medium (1962) with 4.4 μm BA and 0.5 μm IBA, whereas several shoots of apple `Starking Delicious' grew to plantlets. Chromosome counts of shoot apical cells of four clones derived from embryos of `Starking Delicious' showed that three clones were diploids and one clone comprised diploid and haploid shoots, suggesting that at least one clone originated from a microspore. Chemical names used: 3-indolyl-butyric acid (IBA); N6-benzyladenine (BA).