Gibberellic acid and water regime in the flowering induction of Brassocattleya and Cattleya hybrid orchids

The influence of gibberellic acid (GA3) and water regime was evaluated in the flowering induction and quality of two orchid hybrids belonging to the genera Cattleya (C.) and Brassocattleya (Bc.). The experiment was carried out in the Biotechnology and Orchid Culture Sector of Shunji Nishimura Technology Foundation, Pompéia, São Paulo State, Brazil. Five GA3 concentrations (0, 125, 250, 500 and 1,000 mg L-1) were tested through four consecutive leaf applications in adult plants that had already flowered at least once, besides two water conditions (one and four irrigations per week). Applications were performed in October and November for Bc. Marcella Koss and in January and February for C. Irene Holguin. Flowering could not be induced in the latter by gibberellic acid. In Bc. Marcella Koss, the application of 250 mg L-1 GA3 combined with decreased irrigation frequency induced flowering in around 83% plants. By using the same GA3 concentration but frequent irrigation, only 17% plants were induced to flower. The number and size of flowers increased after application of higher GA3 concentrations. This work allowed developing a commercial technique with the use of gibberellic acid (GA3) to induce flowering in Bc. Marcella Koss hybrid orchid.No presente trabalho foi avaliada a influência do ácido giberélico e do regime hídrico na indução e qualidade do florescimento de duas orquídeas híbridas dos gêneros Cattleya (C.) e Brassocattleya (Bc.). O experimento foi realizado no Setor de Biotecnologia e Orquidicultura da Fundação Shunji Nishimura de Tecnologia, Pompéia-SP. Foram testadas cinco concentrações de GA3 (0, 125, 250, 500 e 1.000 mg L-1) em quatro aplicações consecutivas via pulverização foliar, em plantas adultas que já haviam florescido ao menos uma vez, além de duas condições hídricas (uma e quatro irrigações por semana). As aplicações foram feitas nos meses de outubro e novembro para Bc. Marcella Koss e janeiro e fevereiro para C. Irene Holguin. Não foi possível induzir a floração em Cattleya Irene Holguin com o uso de ácido giberélico. Para Bc. Marcella Koss, a aplicação de 250 mg L-1 de GA3, associado à diminuição na frequência de irrigação, induziu cerca de 83% das plantas ao florescimento. Na mesma concentração de GA3, porém em condições de irrigação frequente, apenas 17% das plantas foram induzidas a florescer. O número e o tamanho das flores aumentaram com a aplicação de concentrações maiores de GA3 utilizadas no experimento. A realização deste trabalho permitiu desenvolver uma técnica comercial com o uso de ácido giberélico (GA3) para a indução do florescimento do híbrido de orquídea Bc. Marcella Koss

REGENERATION OF GARLIC PLANTS (ALLIUM-SATIVUM L, CV CHONAN) VIA CELL-CULTURE IN LIQUID-MEDIUM

Aiming at the genetic improvement of garlic cultivars, a cell suspension protocol was established which includes the induction of friable callus, establishment of cells in liquid medium, plating, regeneration, and bulb formation. Calluses of various textures from compact to friable and from green to yellowish were obtained by culturing explants excised from inner leaves of garlic bulbs on Marashig-Shoog (MS) medium with 2,4 dichlorophenoxy acetic acid (2,4-D), (1.1 mg/liter [5.0 mu M]), picloram (1.2 mg/liter [5.0 mu M]), and kinetin (2.1 mg/liter [10 mu M]). Friable callus occurred on MS-A contained 2,4-D alone (1.0 mg/liter [4.52 mu M]) and this callus was used to develop cell suspension cultures, which were maintained in liquid MS-B medium with a 2,4-D/benzyl adenine (BA) (0.5 mg/liter [2.25 mu M]: 0.5 mg/liter [2.22 mu M]) ratio. High plating efficiency was obtained on MS-C medium with different naphthalene acetic acid/BA combinations. Regeneration occurred after transfer of the caulogenic mass to MS-C medium containing 10 mg/liter (74.02 mu M) and 20 mg/liter (148.04 mu M) adenine for 60 days, followed by transfer to adenine-free medium. Plantlets transplanted to soil showed normal phenology. Shoots grown on modified MS medium supplemented with indolylbutryic acid (3.0 mg/liter [14.7 mu M]) stimulated bulb formation by 30 days in culture.30P315015

Efficient Regeneration of Eucalyptus urophylla x Eucalyptus grandis from Stem Segment

The aim of the present study was to establish an efficient regeneration system for the hybrid E. urophylla x E. grandis by means of organogenesis. Stem segments from seedlings were used as explants and cultured in a modified Murashige and Skoog medium (MS), supplemented with 13.2 µM N-phenyl-N'-[6-(2-chlorobenzothiazol)-yl] urea (PBU) and 0.285 µM indole-3-acetic acid (IAA). PBU was a useful growth regulator. After cultivating for 5 d, 96% explants formed callus. After 30 d, the calli obtained were transferred to MS medium containing different combinations of 6-benzyladenine (BA) and naphthalene acetic acid (NAA). Compared with other growth regulator combinations, PBU stimulated more vigorous calli and restrained browning. In addition, a large percentage (91.3%) of the calli induced by PBU showed adventitious buds formation. Shoot elongation was then stimulated on half-strength MS mineral salts medium supplemented with 6.6 µM PBU and 0.285 µM IAA for 20 d. For rooting, the elongated shoots were cultivated on root induction medium containing 2.46 µM indole-3-butyric acid (IBA). Plantlets were then successfully transplanted to a greenhouse. This procedure represented an efficient way of E. urophylla x E. grandis plant regeneration