Number Of Adventitious Shoots Research Articles

In vitro production of flowering shoots in ?German Red? carnation: effect of uniconazole and gibberellic acid

Callus regenerated near the base of senescing petals of flower bud explants of 'German Red' carnation (Dianthus caryophyllus L.) produced adventitious flowering microshoots on MS-medium containing benzylaminopurine (8.9 μM) and naphthaleneacetic acid (2.7 μM). When these microshoots were subcultured with some callus, additional adventitious flowering microshoots were produced from the callus. The production of adventitious flowering shoots continued for many subcultures spanning a period of more than two years. Uniconazole (6.9 μM) increased the number of adventitious shoots formed by as much as two-fold but decreased shoot length by about 50%. In contrast, GA3 (2.9 μM) decreased adventitious shoot formation and increased shoot length. Regardless of the growth regulator treatment, virtually all of the adventitious shoots produced flower buds. Thus, the growth regulators influenced flowering only indirectly by altering the number of adventitious shoots produced in vitro. These results demonstrate that the flowering habit of the adventitious shoots of 'German Red' carnation is highly persistent and the flowering stimulus continues to be transmitted to the newly formed microshoots through the callus.

Floral determination in adventitious shoot meristems regenerated from leaves of day‐neutral tobacco

The developmental patterns of adventitious shoots regenerated from cultured leaf tissue and the petioles of leaf cuttings of flowering day‐neutral tobacco plants were assessed. Leaf tissue, removed from leaves within the inflorescence, was cultured on hormone‐free medium and produced a limited number of adventitious shoots. These shoots produced the same number of nodes that would be produced by a seedling meristem. Most leaf‐cutting derived shoots produced the same number of nodes that would be produced by a seedling meristem prior to flowering, while a few shoots produced very few nodes and flowered. Some plants appeared to be intermediate in response. Results indicated that the developmental state or the developmental response of all petiole cells is not the same. The influence of position and the potential reversibility in developmental fate of cell populations within leaves is discussed in the context of existing theory.

In vitroshoot regeneration of globe artichoke from shoot apices treated with thidiazuron and from mature zygotic embryos treated with cytokinins

Shoot apex explants treated with thidiazuron, and intact mature zygotic embryos, have been used for the first time for adventitious shoot regeneration of globe artichoke (Cyn- ara scolymus L.). Adventitious shoot regeneration from shoot-apex explants of cv. Argos occurred on a basic cultural medium (MS supplemented with 10 mg l1 ascorbic acid, 0.1 mg l'1 IAA (indole-3-acetic acid), 40 g I“1 sucrose and 7 g I'1 agar) to which thidiazuron was added at concentrations between 1 and 5 mg I“1. The effect of thidiazuron was equally as efficient as that of the commonly used cytokinins kinetin (6-furfurylaminopurine) and BAP (6-benzylaminopurine). The explants initially treated with thidiazuron continued to produce adventitious shoots when subcultured onto cytokinin-free or thidiazuron-free medium, but this did not occur when kinetin or BAP was initially applied to the explants. Intact mature zygotic embryo explants, cultured like the shoot apices, produced a high number of adventitious shoots when the medium was...

Adventitious shoot formation from in vitro leaf explants of carnation (Dianthus caryophyllus L.)

A regeneration procedure was developed for carnation (Dianthus caryophyllus L.) using leaves from in vitro grown plants. Leaves were carefully removed from the stem using forceps. Basal explants were incubated on Murashige-Skoog medium with 0.3 mg l−1 benzyladenine (BA) and 0.3 mg l−1 α-naphthaleneacetic acid (NAA). After 2 weeks, adventitious shoots developed at the bases of the explants. The position of leaves on the plant appeared to be important, the youngest leaves just below the apical meristem giving the best regeneration results. The regeneration procedure was generally applicable, 24 out of 25 tested cultivars from various carnation types showing regeneration. Using petals as starting material, 37 out of 55 cultivars produced shoots although, as a result of premature flowering, it was usually impossible to transfer regenerated shoots to soil. Regenerants from leaf explants showed no aberrant plant growth. A number of factors were analysed to optimize the procedure. Both BA and NAA in the range 0.1–0.9 mg l−1 affected the average numbers of shoots per regenerating explant, but not the regeneration percentage. The highest number of adventitious shoots was obtained on medium containing 0.9 mg l−1 BA and 0.3 mg l−1 NAA. The two leaves of a leaf pair responded differently, the second leaf to be removed from the stem showing the highest regeneration percentage. Combining the optimum conditions, 65% of the explants showed regeneration with an average of ten shoots per explant.

CALOGENESIS AND ORGANOGENESIS OF SOMATIC MATERIAL FROM APPLE SEEDLINGS (MALUS DOMESTICA BORKH) AS AFFECTED BY SOURCE MATERIAL AND DARK PERIOD.

The aim of this work was to study different apple of somatic material as callus and adventitious shoots are concerned, for further utilization in the research of somaclonal variation. The somatic materials were: leaf discs, cotyledons and hypocotyls of Gala apple seedlings, cultivated in a MS medium added by B5 vitamins in addition to (in mg/l): BAP (1,0), NAA (0,5) mio-inositol (100,0) sucrose (30,0 g/l) and solidified in agar (6,0 g/l). The several times of explant exposition to the dark affected the final callus weight. Callus weight derived from leaf discs were higher than those for cotyledons and hypocotyls. Explants exposed directly under light or up to two weeks in the dark showed less percentage of regenerative callus as compared to those of three weeks in the dark. The leaf explants presented the highest percentage of regenerative callus. The least response was obtained for those derived from hypocotyls. The highest number of adventitious shoots was obtained keeping the explants three weeks in the dark as compared to directed light exposition.

Vegetative Regeneration of Fucus Rockweed Canopy as a Mechanism of Secondary Succession on an Exposed Rocky Shore

Canopy regeneration by vegetative regrowth from damaged holdfasts has been examined in two species of rockweed, Fucus vesiculosus and Fucus evanescens. About 20-30% of experimentally damaged holdfasts sprouted large numbers of adventitious shoots, even when the basal tissue had been cut to less than 2 mm thickness. Vegetative regrowth was observed from minute amounts of holdfast tissue. This vegetative sprouting appears more important in the F. vesiculosus zone than in the F. evanescens zone. Comparison of Fucus growth in plots with sterilized or damaged holdfasts provided estimates of the relative importance of recuitment and vegetative regrowth to canopy recovery (...)

Adventitious shoot regeneration from leaf explants of tissue cultured and greenhouse-grown raspberry

Adventitious shoot regeneration was observed using leaf-petiole explants from shoot-proliferating cultures of ‘Comet’ red raspberry (Rubus idaeus L.). A maximum regeneration rate of 70% (3.7 shoots/explant) was obtained using 4.5–9.1 μM (1–2 mg l−1) N-phenyl-N′-1,2,3-thiadiazol-5-ylurea (thidiazuron or TDZ) with 2.5–4.9 μM (0.5–1 mg l−1) 1H-indole-3-butanoic acid (IBA) or 2.3 μM (0.5 mg l−1) TDZ with 4.9 μM (1 mg l−1) IBA in modified Murashige-Skoog medium. TDZ was more effective than N-(phenylmethyl)-1H-purin-6-amine (BA) at promoting regeneration in combinations tested with IBA (maximum 50% regeneration rate; 1.8 shoots/explant). Variation in the agar concentration or incubation temperature, orientation or scoring of the leaf-petiole explants and use of separate leaf or petiole explants had no effect on shoot regeneration. Incubation in the dark for 1, 2 or 3 weeks prior to growth in the light did not influence the percent regeneration rate but depressed the number of adventitious shoots. Explant source, from micropropagated shoots or greenhouse-grown plants, had an effect on shoot regeneration that was genotype dependent. Only 8 of 22 (36%) raspberry cultivars were capable of regeneration from leaf explants derived from greenhouse-grown plants.

Synthesis and Characterization of Nicotiana-Solanum Graft Chimeras

Intergeneric Nicotiana tabacum L./Solanum laciniatum Ait. graft chimeras were produced from decapitated grafts made between these two graft compatible species. Graft unions were treated with or without either the auxin, p-chlorophenoxyacetic (p-CPA) or the cytokinin, benzylaminopurine (BAP). While BAP was inhibitory to shoot formation, p-CPA increased the number of adventitious shoots and raised the frequencies of shoot-forming grafts obtained. Approximately 9% (14/151) of the shoots produced at p-CPA-treated graft unions were intergeneric chimeras. The auxin application significantly increased levels of chimeral shoot recovery numbers thus indicating a direct auxin effect on chimeral shoot production. The types and numbers of chimeras produced were independent of the scion/stock graft combination employed. All chimeras appeared to arise initially as mericlinal or sectorial chimeras, with a proportion of the former ones (5/14) stabilizing into periclinal chimeras. The morphological characteristics of these latter chimeras were compared with those of the two parental species. The LII layer of species determined the characteristics of the vegetative and floral components. However, the LI layer modified the qualitative traits of both components. The LIII layer on the other hand altered the quantitative traits of the vegetative organs and the flower. This layer also determined the growth type, breeding behaviour and inflorescence type of synthesized chimeras. These organizational functions of the LIII layer have not been reported previously.

Cultural factors influencing adventitious shoot and plantlet formation from slash pine cotyledons

Cultural factors affecting in vitro shoot and subsequent plantlet formation of slash pine (Pinus elliotti Engelm.) cotyledons were investigated. Basal media composition, N6-benzylaminopurine (BAP) concentration and exposure time significantly influenced bud induction in cotyledons cultured under a continuous photoperiod of 35–40 μmol m−2 s−1 at 24 ± 1 °C. The largest number of adventitious shoots was obtained after 28 days exposure to 66 μM BAP-supplemented modified Gresshoff and Doy 1 (GD1) medium. Relatively high frequencies of large shoots were obtained after a 14-day exposure to 22 μM BAP-supplemented Brown and Lawrence (BL) or 66 μM BAP-supplemented GD1. Adventitious shoots derived from 21- or 28-day exposures to BAP developed more slowly and were smaller in size than those derived from a 14-day exposure to the cytokinin. Shoot differentiation and subsequent growth were also influenced by basal media, media concentration, and presence of activated charcoal in the medium. The percentage of cotyledons forming shoots was highest on half-strength GD1 medium containing activated charcoal. Rooting was achieved in vitro under a continuous photoperiod of 60–70 μmol M−2 S−1. Roots were formed when excised shoots were planted on GD 1/2 medium supplemented with 2.68 μM 1−1a-napthaleneacetic acid (NAA) with or without BAP for 14 days. The proposed technique of slash pine propagation using cotyledon explants can produce up to 100 seedlings per embryo.

Concentrações de 6-benzilaminopurina no desenvolvimento in vitro de embriões de pêssegos e nectarinas precoces

Objetivando melhorar o desenvolvimento in vitro de embriões de pêssegos e nectarinas, de maturação precoce, adicionou-se, em meio básico de cultura, o regulador de crescimento 6-benzilaminopurina (BAP) nas concentrações de 0,5,10,15 e 20µM. Esse meio consistiu na solução salina de Murashige & Skoog acrescido de tiamina, 1mg/l; ácido nicotínico, 0,5mg/l; inositol, 100mg/1, glicina, 250mg/l; glutamina, 500mg/l; asparagina, 250mg/l, ácido giberélico, 0,1mg/l; sacarose, 30g/l, e ágar, 6g/l. A melhor taxa de desenvolvimento dos embriões, após 30dias de cultura, ocorreu nas concentrações de 5 e 10µM de BAP, com uma emissão média de 4,5 brotos por embrião. Nas concentrações de 15 e 20mM de BAP, o número de brotações foi maior, porém com menor aproveitamento, devido à presença dos sintomas indesejáveis de vitrificação. O BAP não eliminou, totalmente, a roseta e o ananismo fisiológico dos embriões.

Effect of bulb storage on shoot regeneration from floral stems of tulipin vitro

High numbers of adventitious shoots were regenerated from floral stem explants of the tulip cultivar Merry Widow in cultures set up in the middle of December. Further bulb storage led to a decline in the regeneration of shoots which was related to the physiological age, and to the water and glucose contents of the explants. Floral stems which were immature and short (15 to 16 mm) and which contained high amounts of water and glucose produced the most shoots.

Factors involved in shoot elongation and growth of adventitious and axillary shoots of three apple scion cultivarsin vitro

Some factors involved in shoot elongation and leaf enlargement of adventitious apple shoots in vitro were investigated. A system was established to produce large numbers of adventitious shoots for this study. Leaves were harvested from proliferating cultures of three apple scion cultivars, cut into two segments, and plated onto three regeneration media. Adventitious shoots formed best on a modified Murashige and Skoog medium supplemented with thidiazuron (3 |iM) and naphthaleneacetic acid (5.4 ^M). Large (15+ mm width) leaves regenerated significantly better than smaller ones. The cut surface of the leaf segments produced the highest number of regeneration sites. Shoot proliferation medium with 6-benzylaminopurine (4.44 (iM) and kinetin (13.95 (xM) was significantly better than the other media for producing tall shoots and satisfactory proliferation. Leaf expansion was significantly improved when shoots were grown on proliferation medium with either 2-isopentyladenine or kinetin alone.

Chromosome Behaviour in Regenerants from Excised Leaf Discs ofSolanum SarrachoidesSendt.

SUMMARYThe present communication deals with the study of chromosome behaviour in plants, regenerated in vitro through direct adventitious bud formation from leaf segments in Solanum sarrachoides Sendt. Highest number of adventitious shoots was obtained in MS semisolid medium supplemented with 2iP (2 mgl−1) as the only growth regulator. Addition of IAA was necessary in the later phase of culture to obtain better growth and development of shoots with well-defined leaves, roots, flowers and fruits. Analysis of the pollen mother and root tip cells of the regenerants showed n = 12 and 2n = 24 chromosomes respectively. Hyperdiploids along with the normal diploid cells were also recorded in low percentage.

Plant regeneration from apple seedling explants and callus cultures

Leaf, cotyledon, and hypocotyl explants were obtained from 3-week-old seedlings of open-pollinated ‘Golden Delicious’ (Malus domestica bork H.) grown in vitro. They were placed on modified Murashige and Skoog (MS) medium containing B5 vitamins, sucrose and agar, supplemented with 6-benzylaminopurine (BAP) and α-naphthaleneacetic acid (NAA), and maintained at 25°C±2 in the light or in the dark to assess morphogenetic responses. Leaf and cotyledon explants cultured in the dark for an initial 3 weeks, then transferred to light for 4 weeks, produced 5- to 20-fold more adventitious shoots than those cultured for 7 weeks in the light. Conversely, light did not significantly influence the number of adventitious shoots formed on hypocotyl explants. Five-minute daily exposures of leaf explants to red light (651 nm) suppressed adventitious shoot formation by 80%; five-minute exposure to far-red light (729 nm) immediately following the red light counteracted the red suppression.

Influence of explant selection on the shoot-forming capacity of juvenile tissue of Pinusradiata

The shoot-forming capacity of Pinusradiata D. Don juvenile explants under tissue culture conditions was examined. Three types of explant were used: whole embryos; cotyledons excised from whole embryos which had been cultured for 1 week on the shoot initiation medium; and cotyledons excised from 1-week-old aseptically germinated seeds. The average number of rootable shoots produced per seed in 12–13 weeks was 9 for excised embryos, 18 for their separated cotyledons, and 180 for the cotyledons from germinated seeds. Induction of a smooth-surfaced, yellow–green, nodular meristematic tissue appears to be a requirement for the formation of large numbers of adventitious shoots. By extending the culture period from 12 to 24 weeks more than 1300 shoots were formed from the cotyledons of one germinated seed. To date, no other conifer tissue culture method has been reported to give such a large number of adventitious shoots of the same clone in a first generation.

THE GROWTH OF TULIP TISSUES IN VITRO

Large numbers of adventitious shoots have been induced to form in vitro on floral stem sections of Tulipa gesneriana L. cultivar Merry Widow. In comparison with explants of scale and axillary bud, floral stem tissues showed the greatest potential for shoot production. A modified Murashige & Skoog medium contained inorganic salts and vitamins at full strength and supplemented with benzylamino-purine and napthalene-acetic acid at 1 mg‾1 induced shoots on 70%-90% of floral stem explants. The stage of development of the bulb was found to be an important factor in determining the ability of explants to regenerate shoots. The shoot producing potential of floral stem tissues was greatest during the 'dormant' phase of the bulbs, but the ability to produce shoots was lost once rapid extension growth and greening of the floral stem had commenced. Morphogenesis in vitro was found to be influenced by the origin of explants from within the floral stem. A study of endogenous plant growth regulators was made within the floral stem in order to elucidate their role in the organogenetic processes occurring in vitro. A study of histological and morphological development in vitro showed that the shoot-like structures arise from the epidermal cell layer and have the potential to form whole plants.

Callus and adventitious shoot formation in excised embryos of white pine (Pinus strobus)

Excised embryos from 2- to 3-year-old seeds of white pine (Pinus strobus) were grown on Murashige and Skoog medium supplemented with several concentrations of different plant hormones. In the basal medium the embryos developed into normal seedlings. At 1–2% sucrose concentration in the medium, the primary root of the embryo did not grow well, while at 3–6% sucrose concentration normal growth of the primary root was observed in most of the embryos.Gibberellic acid at a wide range of concentrations (0.01–20.0 mg/L) had little effect on the growth of the seedling shoot while growth of the primary root was generally suppressed. In the presence of 0.01–2 mg/L of NAA, 2,4-D, or IBA, the embryos proliferated to form friable green callus. Callus formation was further enhanced by a cytokinin (0.1-5 mg/L). IBA (1–5 mg/L) in some embryos induced the formation of adventitious shoots from the hypocotyl region. Similarly, TIBA (0.5–1.0 mg/L) induced the formation of adventitious shoots but they were formed at the tips of embryonic cotyledons. The number of adventitious shoots per embryo was increased by zeatin or benzyladenine.The callus obtained on 2,4-D or IBA could be easily subcultured. In spite of several treatments with different auxins, cytokinins, and their combination, no differentiation of roots or shoots was observed in callus cultures.

Mutation breeding of Chrysanthemum morifolium Ram. using in vivo and in vitro adventitious bud techniques

During experiments, which are being carried out to study the factors which control the process of adventitious bud formation in vivo on detached leaves of Chrysanthemum morifolium Ram, adventitious shoots were produced from leaves, irradiated with 500 rad of X-rays. The most important but disadvantageous result was that the majority of the adventitious shoots proved to be of a chimeral nature and obviously developed from more than one cell. An in vitro adventitious bud technique was developed using different types of explants. Pedicel segments regenerated the highest number of adventitious shoots and, moreover, they developed faster as compared to explants of young flower heads or leaves. The mutants produced by irradiating the various explants were almost exclusively of a solid (non-chimeral) nature. In addition, histological observations suggest that single epidermal cells are involved in the initiation of the adventitious shoot apices. The optimum dose for mutant production is approximately 800 rad X-rays. Rather often, more than one phenotypically identical mutant was found, which was always derived from the same explant. They could for instance originate from a multi-apical meristem formed by a single mutated cell.

Vegetative propagation of Chrysanthemum morifolium Ram. in vitro

Young segments of flower pedicels of the Chrysanthemum morifolium cultivars ‘Super Yellow’ and ‘Bravo’ regenerated rapidly high numbers of adventitious shoots in vitro. The influence of the explant-length, growth regulators, sugar, vitamins and minerals on adventitious shoot formation of both cultivars was examined. 11 cultivars, representing several important groups of cultivars, produced adventitious shoots on the same basic medium. Small shoots were separated and transferred to different media in vivo or in vitro for the initiation of adventitious roots and the consequent production of plantlets. The significance of this method for vegetative propagation, storage and mutation breeding is discussed.

A suggested method for investigating L1 constitution in periclinal potato chimeras

The most reliable way to study the nature of L1 in suspected periclinal chimeras is to investigate plants derived from L1 tissue only. Induction of adventitious buds and shoots from dedifferentiated epidermal tissue only, has proved to be easy in several ornamental plants such asSaintpaulia andStreptocarpus, but for potato until now only some incidental successes have been obtained using detached leaflets with different treatment. If this method could be developed to give adequate numbers of adventitious shoots, it is suggested that it could be used on a monochlamydeous (periclinal) chimera to prove the L1 origin of these shoots.