Showing papers on "Micropropagation published in 1983"

Possibilities and constraints in the regeneration of trees from cotyledonary needles of Picea abies in vitro

Abstract: Although use of embryonic or seedling tissues for mass clonal micropropagation in vitro in conifer reforestation programmes is questionable, there is a potential application in the regeneration of plants from scarce and costly seed derived from controlled pollination. In addition, in vitro culture shortens considerably the lag phase in numbers during the initial stages of vegetative propagation via rooted cuttings. Successive steps of the present technique are described whereby cotyledonary needles (secondary explants) were subcultured on a hormone-free medium after administration of cytokinin or auxin to 14-day-old seedling (primary) explants of Picea abies. For bud induction, N6-benzyladenine (BA) was applied either as a short-duration (3 h), high-concentration (125 μM) pulse or by vacuum infiltration and incubation in a BA-containmg (5 μM) infusion medium. Induced adventitious shoots were elongated with the aid of far-red light and rooted in vivo after a long-duration (12 h), high-concentration (625 μM) application of indolebutyric acid. Pulse and infusion treatments resulted in the induction of greater numbers of adventitious buds (average of 12 per needle) over a three to four week shorter culture period than was the case with the conventional inclusion of growth regulators in the agarified medium. No exogenous auxin was required in the bud-induction programme; its inclusion even at nanomolar levels promoted histo- rather than morphogenesis. In cotyledonary needles, to the primary explants of which BA was applied as a pulse or by infusion, the cell divisions which gave rise to the meristemoids from which adventitious buds were produced, appeared to commence mainly in undifferentiated hypodermal layer cells but also in the mesophyll immediately below. By contrast, where BA was incorporated in the agarified medium the first divisions occurred mainly in cells of the epidermal layer. A number of factors affected plantlet regeneration, for instance seed variability, age of seedlings, and mode of application of growth substances. It should also be accepted that the xeromorphic nature of the conifer leaf might impose physiological and morphological constraints on its culture in vitro that could militate against easy morphogenic manipulation. It is deemed essential that the current mean ratio of regenerated plants to cotyledonary needles of 1:1 be increased 10 to 20 fold in order to approach commercial feasibility.

Plants from Test Tubes: An Introduction to Micropropagation

Abstract: 'Plants from Test Tubes' remains one of the most user-friendly yet thorough guides to the science of ornamental plant tissue culture. This helpful companion develops the grower's understanding of the processes involved, whilst detailing the steps to design, equip and operate a laboratory as well as providing a culture guide to dozens of species.

Studies of VA mycorrhizae in vitro: mycorrhizal synthesis of axenically propagated wild cherry (Prunus avium L.) plants

Abstract: An increasing number of woody plant species can be axenically propagated using plant tissue culture methods. These techniques produce high quality healthy plants but transplant problems often arise due to their being susceptible to different environmental stresses. Mycorrhizae can play a vital role in plant nutrition and survival and their introduction during the production of axenically propagated plants could contribute to the success of this technique. Using a simple method for axenic establishment and direct observation of VA mycorrhizal cultures, in vitro mycorrhizal synthesis of a woody plant species has been obtained for the first time using axenically propagated plants of Prunus avium L. (wild cherry) and the VA fungus Gigaspora margarita.

Process for the sterile micropropagation of plant material

Abstract: The invention relates to a process for the production of propagating material of plants by micropropagation in sterile tissue culture which comprises (a) planting sterile shoot cuttings of plants in solid nutrient medium in a suitable flask, filling up the flask with a suitable liquid nutrient medium optionally containing a growth regulator and growing the shoots in the submersed system; thereafter (b) cutting up into pieces the ramified culture thus obtained which contains a number of lateral buds and shoots, rooting the top-end shoots and planting the same after adaptation, and subjecting the cuttings prepared from the lower and middle parts of the shoot cultures to further cultivations according to step (a); and repeating steps (a) and (b) until the desired number of top-end shoots is reached.

Avocado callus and bud culture

Abstract: Parameters influencing viability, callusing and shoot elongation of avocado (Persea Americana Mill.) leaf sections, axillary buds and stem sections were evaluated. Seedlings of 'Lula' and 'Waldin' were used. Explants taken from older leaves, oriented with the abaxial surface in direct contact with the medium, with 2,4(dichlorophenoxy)acetic acid (2,4-D) (1 mg/liter) and maintained at 27°C exhibited optimum callusing. Elongation of axillary buds was enhanced by inclusion of gibberellic acid (1 mg/liter) in the medium and culture at 30°C. Callusing of stem sections was better in the light and when the medium was supplemented with benzyladenine (1 mg/liter). Micropropagation using shoot tips has been experimentally achieved with numerous woody plant species. Recently, success using shoot tips from avocado seedlings was reported (5). An alternative to using shoot tips in micropropagation involves formation of callus from various parts of the plant followed by differentiation into shoots or embryoids. Proliferation and differentiation of the callus formed may be influenced by several factors. The cotyledons (2, 3, 4, 6), fruit mesocarp (2, 3), peduncle (9), buds (8, 11) and stem tissue (10, 11) of avocado have all been found capable of forming callus. Cultures maintained in the dark at 25-27°C compared to other temperatures formed callus more readily (3, 4, 7). Cytokinins were necessary for the growth of callus from fruit medocarp tissue but not for that derived from cotyledons (2). Culture of avocado leaves and callus formation from them has not been reported. The present study examines the influence of: 1) explant source, orientation in the media and culture temperature on viability and callusing of leaf explants, 2) gibberellic acid (GA) and temperature on elongation of axillary buds, and 3) light intensity, 2,4-D and benzyladenine (BA) on callusing of stem sections of avocado.

Induction of Adventitious Buds and Globular Embryoids on Seedlings of Trifoliate Orange (Poncirus trifoliata)

Abstract: The adventitious buds and globular embryoids were obtained from a nucellar seedling of a trifoliate orange by the use of two kinds of plant hormones, i. e., α-naphthaleneacetic acid (NAA) and 6-benzyl aminopurine (BA). The highest frequency of induction of the adventitious buds was obtained, when 1.0 mg/l NAA and 5.0 mg/l BA were supplemented to the culture medium. Adventitious root formation was promoted by the supplement of 2.0mg/l NAA to the culture medium. A micropropagation scheme for a trifoliate orange was put forward.