Abstract
Dierama latifolium N.E. Br. was propagated in vitro using corm cultures. Shoots were induced from corm explants when grown on solidified Murashige and Skoog (MS) medium supplemented with 30 g/liter sucrose, 100 mg/liter meso-inositol, and 0 or 0.5 mg/liter NAA. Shoot proliferation was not improved by the addition of BA to the initial culture medium. Multiple shoots were induced by transferring those produced in vitro, to a modified MS medium supplemented with 0.5 or 1.0 mg/liter BA. Rooting of these shoots was induced by subculturing single excised shoots, 5-10 mm in height, either a hormone-free basal medium or a BM supplemented with 0.5 or 1.0 mg/liter NAA. Utilizing this technique, about 90 plants could be produced from a single corm within 12 months. Chemical names used: 1-napthalenacetic acid (NAA); N-(phenylmethyl)-1H-purin-6-amine(BA).
We report the results of serial studies aimed at clarifying several factors affecting organogenesis in rhizome culture of temperate Cymbidium species and their hybrids. The growth patterns and regeneration ability of rhizomes derived from asymbiotic seed or shoot tip culture vary according to media composition, kinds and concentrations of plant growth regulators, culture conditions, and species and varieties. N6-benzyladenine was the best cytokinin for inducing shoot formation, for switching rhizome tissues into protocorm-like bodies, and for directly forming multiple shoots from branched rhizomes. Activated charcoal appeared to be necessary for producing healthy plantlets and for stimulating shoot growth at levels of 0.1% to 0.3% but concomitantly decreased rhizome growth. Sucrose at 5% was the most effective concentration for shoot induction from rhizomes. The above results support the conclusion that organogenic pathways between tropical, subtropical, and temperate Cymbidium species may be controlled by the genetic backgrounds of the species or cultivars.
Abstract
Lateral buds excised from unrooted cuttings of Maranta leuconeura E. Moor. ‘Kerchoviana’, prayer plant, were cultured on Linsmaier and Skoog (LS) medium supplemented with various combinations of N6-benzylaminopurine (BA), kinetin, α-anaphthaleneacetic acid (NAA), and 3-indoleacetic acid (IAA) for the production of multiple shoots and complete plants. Of 48 combinations of growth regulators, 4 produced the most vigorous, well-formed shoots after a culture period of 6 weeks: 2.0 mg·liter-1 kinetin, 0.2 mg·liter-1 BA, 0.2 mg·liter-1 BA plus 0.1 mg·liter-1 NAA, and 2.0 mg·liter-1 kinetin plus 1.0 mg·liter-1 IAA. Enhanced shoot production occurred when shoots were transferred at 12-week intervals and when they were maintained on 0.2 mg liter-1 BA. Complete plants with strong, fibrous root systems were produced after the shoots were transferred to basal medium lacking growth regulators for 3-4 weeks.
Abstract
Cultured shoot tips and lateral buds from greenhouse-grown rose (Rosa hybrida L. cv. Improved Blaze) proliferated multiple shoots on a basal medium (MS salts, vitamins, glycine, sucrose, and agar) supplemented with 3.0 mg/liter 6-benzylamino purine (BA) and 0.3 mg/liter indoleacetic acid (IAA). A 3-fold multiplication was achieved from freshly explanted terminal shoot tips or lateral buds after 8 weeks. Reculture of in vitro-derived shoots onto the same medium resulted in a 6-fold increase in 8 weeks. Roots could be initiated from about 50% of these shoots after transfer to a medium containing 0.3 mg/liter IAA and 0 or 0.3 mg/liter BA. Regenerated plants were successfully transferred to soil after 2 weeks.
Vegetative long-shoot buds, greenwood stems, and immature needles of 20-year-old western larch (Larix occidentalis Nutt.) were cultured to induce multiple bud formation. Explants were collected year-round and cultured on a modified Schenk and Hildebrandt (SH) medium containing 6-benzyladenine (BA) at 0, 1, 5, 10, 50, or 100 μm. Multiple buds were produced on buds and stems with terminal meristems, but not on needles or stem sections. The induction of de novo buds and development of axillary buds required BA at 1 to 10 μm; higher concentrations of BA were less effective. More explants formed multiple buds on SH than on modified Murashige and Skoog (MS) media. Multiple buds formed on more buds and stems excised during the growing season than from dormant buds. Buds cultured on media containing gibberellin died within 6 weeks; auxin caused bud elongation but no multiple buds formed. Chemical names used: N-[(trichloromethyl)thio]-4-cyclohexene-1,2-dicarboximide (captan); 6-benzyladenine (BA); 1H-indole-3-butyric acid (IBA); 1H-indole-3-acetic acid (IAA); gibberellin (GA4+7).
Abstract
Rapid clonal propagation of Alnus glutinosa was achieved in vitro using lateral buds excised from greenhouse grown, juvenile stock plants. Multiple shoot development occurred in 50% of the cultures after the first subculture (7–8 weeks after initial explanting) using a low salt, woody plant medium containing 1 μM 6-benzylaminopurine (BA). Microshoots were removed from pro-liferating tissues and rooted in a conventional potting medium under high humidity prior to establishment in the greenhouse.
Abstract
Clonal multiplication of carnation (Dianthus caryophyllus L.) was accomplished in three stages: 1) shoot tip culture initiation stage, 2) shoot multiplication stage, and 3) rooting stage. The culture medium for the initiation stage was examined by comparing various inorganic salt mixtures, vitamin mixtures, carbohydrates, growth regulators, agars, pH’s, and additional supplements for their effect on growth and development of multiple shoots from shoot tips. When shoot tips (ca. 1 mm high) were grown on a modified Murashige and Skoog medium with 10 µM kinetin and 1 µM NAA, apical dominance was counteracted and morphologically normal shoots proliferated rapidly. Transferring these cultures after 4 wk to 100 ml flasks (one per flask) with 50 ml of same medium without agar and supplements, and with the kinetin concentration reduced to 2.5 µM, resulted in an average per original shoot tip of 28 shoots over 2 cm in height being produced in another 3 weeks. These shoots were rooted in BR-8 blocks or Jiffy-7 peat pellets under intermittent mist. Plantlets rooted in these supports were transferred easily to greenhouse conditions. Incorporation of carnation micropropagation into a pathogen-free propagative stock program should not be difficult, and might prove beneficial even if large scale use is limited by economic considerations.
Abstract
N-(3-methyl-2-butenyl)-1H-purin-6-amine (2iP) has been used to promote multiple shoot formation in previous tissue culture studies with ericaceous plants (1, 3-7). Fordham et al. (3), however, found that (E)-2-methyl-4-(1H-purin-6-ylamino)-2-buren-1-ol (zeatin) was the most effective cytokinin for stimulating shoot proliferation of cultured Exbury azalea (Rhododendron sp.). This study was conducted to determine if highbush blueberry is similar to Exbury azalea in its response to zeatin.
Shoot tips, approximately 3-5mm, were isolated from corms of young greenhouse-grown plants of cocoyam, cultivar South Dade White. After preliminary evaluations, the initiation media evaluated were B5 basal salts supplemented with 0.05 μM NAA with 5μM BAP, 20μM BAP or 2μM TDZ. The above media were in the form of liquid medium in flasks on a rotary shaker, liquid medium with filter paper bridges, stationary liquid medium without filter paper and solidified medium with 0.4% agar. TDZ stimulated greater growth with multiple shoot formation. Liquid media either in the shaker or stationary form were more effective in terms of growth. Shoots were subsequently evaluated for multiplication with 1μM TDZ and 5μM BAP with 0.05μM NAA producing greater shoot numbers. Over 30 plants have subsequently been rooted and acclimatized under mist or humidity tent.
The resistance of 48 highbush blueberry cultivars and selections to the blight phase of mummy berry disease, incited by the fungus Monilinia vaccinii-corymbosi (Reade) Honey, was examined in relation to percent Vaccinium angustifolium Ait. ancestry, season of fruit maturity, and shoot growth during the primary infection phase. Correlations of percent blighting with percent V. angustifolium ancestry were significant across 3 years, but correlations with fruit maturity were significant in only 2 of 3 years. Correlations of percent blighting with early shoot growth were significant in both years measured, with r values of 0.54 in 1994, 0.83 in 1995, and 0.83 across years. A multiple regression found only shoot growth highly significant for susceptibility and rendered V. angustifolium ancestry and season of fruit maturity nonsignificant. Resistant cultivars exhibiting early shoot elongation suggest that resistance can be either biochemically or escape based.