MODIFICAÇÕES NO MEIO DE CULTURA, FOTOPERÍODO E TEMPO DE CULTIVO AFETAM O ALONGAMENTO E ENRAIZAMENTO IN VITRO DE BANANEIRA CV. PACOVAN

No intuito de elevar as taxas de sobrevivência durante a etapa de aclimatização e posterior plantio a campo, avaliou-se o enraizamento in vitro de bananeira cv. Pacovan, em diferentes concentrações de sais MS e de sacarose. Utilizou-se DIC, esquema fatorial (6x2x3), com seis meios de cultura [sendo três concentrações de nutrientes do meio MS (100%; 50% de macronutrientes; e 50% dos sais macro e micronutrientes), e duas concentrações de sacarose (1,5/3,0%)], dois fotoperíodos (12/16 h) e três tempos de cultivo (21, 28 ou 35 dias) e seis repetições/tratamento. Analisaram-se: altura da planta, número de folhas/planta, massas frescas e secas das partes aérea e radicular. Para altura da planta, massa fresca da parte aérea e radicular, o meio MS 50% dos sais + sacarose (1,5%) com fotoperíodo de 16 h e tempo de cultivo de 35 dias foi satisfatório. Para massa seca da parte aérea foi MS 50% de sais + sacarose (3%), e para massa seca da parte radicular, MS 100% + sacarose (3%) (em 12hs/28 dias e 16hs/21 dias). Para o alongamento/enraizamento in vitro da bananeira cv. Pacovan sugere-se MS 50% de sais (macro e micronutrientes), redução ou manutenção de sacarose (1,5 ou 3%) em 16h/35 dias de cultivo.Palavra-chave: Musa spp., propagação in vitro, sistema radicular. CHANGES IN CULTURE MEDIUM, PHOTOPERIOD AND TIME OF CULTIVATION AFFECT THE IN VITRO ELONGATION AND ROOTING OF BANANA CV. PACOVAN ABSTRACT:In order to achieve high rates of survival during the acclimatization and later planting in the field, was evaluated the in vitro of banana cv. Pacovan plants under different concentrations of sucrose and MS basal salt mixture. The experiment was assembled in a DIC, in 6x2x3, six different culture media [three different MS salt mixture concentrations (100%; 50% of macronutrients; and 50% of macro/micronutrients) and two sucrose concentrations (1.5/3%)], two photoperiods (12/16 hours) and three cultivation times (21, 28 or 35 days). Each treatment was composed by 6 replicates. Plant height, number of leaves/plant, fresh and dry weight of roots and shoots, were analyzed. Satisfactory results for plant height and shoot and root fresh biomass were observed in MS with macro/micronutrients (50%) + sucrose (3%), 16 hours/35 days. The highest values of shoot dry weight were observed in MS with macro/micronutrients (50%) + sucrose (3%); the highest root dry weight was achieved with MS 100% + sucrose (3%) (12hs/28 and 16hs/21 days). The suggested medium for the in vitro elongation and rooting stage of banana cv. Pacovan is the MS with 50% of salts (macro and micronutrients), reduction or maintenance of sucrose (1.5 or 3%) in 16h/35 days of cultivation.Keywords: Musa spp., in vitro propagation, root system

Induction of somatic embryogenesis in two cultivars of anthurium analysed by scanning electron microscopy

Somatic embryogenesis is an advantageous tool in the commercial production of micropropagated anthurium plantlets. As such, the aim of this study was to establish a protocol for the induction of somatic embryogenesis in Jureia and Luau cultivars. Defoliated nodal segments, 1.0 cm in length and containing one bud, were used as explants. The experimental design was completely randomised, in a 2 x 3 x 5 factorial scheme (cultivar: Jureia and Luau x auxin: 2,4-D, NAA and Picloram x concentration: 0, 2.5, 5.0, 7.5, and 10.0 μM), with 30 treatments in a scheme of plots split over time (15, 30, 45, 60, 75 and 90 days). The anatomy and percentage of embryogenic callus formation were analysed. The structures formed, analysed by scanning electron microscopy, corresponded to embryogenic calli. The Luau cultivar was superior in forming embryogenic calli. For the two cultivars, among the auxins under study, NAA demonstrated a greater induction potential for somatic embryogenesis, with the concentration of 7.5 μM giving the highest mean values. The 90-day evaluation period showed the maximum formation of embryogenic calli; however, mean values were fairly similar to the 75-day evaluation period. To induce embryogenic calli, therefore, it is suggested that the nodal segments be inoculated into a culture medium with added NAA growth regulator at a concentration of 7.5 μM, and that the explants remain in this medium for 75 days after inoculation

The in vitro multiplication of anthurium cv. Eidibel

Anthurium is one of the most marketed species in international floriculture. The availability of sufficient plants of phytosanitary quality is a limiting factor in their commercial cultivation. Micropropagation is the most common technique used in producing plantlets on a large scale. The aim of this study was to determine the most suitable relationship between growth medium, BAP concentration and photoperiod for increasing the in vitro multiplication rate of the ‘Eidibel’ cultivar. A completely randomised design was used in a 2 x 9 x 2 factorial scheme with 20 replications. The treatments comprised combinations of two types of growth medium (MS and Pierik), nine concentrations of BAP (0.0; 1.11; 2.22; 3.33; 4.44; 5.55; 6.66; 7.77 and 8.88 μM), and two photoperiods (12 and 16 h). The number of shoots per explant (NSE) and percentage of explants forming organogenic calli (FOC) and roots (FR) were evaluated after 60 days. The highest values for NSE, 3.66 and 4.69, were obtained in the MS and Pierik growth media, containing 8.88 μM and 4.85 μM BAP respectively. The NSE was higher under the 12-hour regime in the MS medium, and equal under the two photoperiods in the Pierik medium. The lower the BAP concentration, the greater the percentage of root formation and the smaller the percentage of organogenic calli. The Pierik medium is recommended for the production of micropropagated ‘Eidibel’ plantlets, with the addition of 4.85 μM BAP, under a photoperiod of 12 h

Photoperiod and growth regulators on in vitro shoot induction in Heliconia latispatha

Considering the growing economic importance of tropical flowers and the advantages of techniques applied to the in vitro cultivation of these plants, it is necessary to carry out studies to evaluate growth in species such as Heliconia latispatha. The aim of this study therefore, was to evaluate in vitro shoot induction for different concentrations of BAP and NAA and as a function of the photoperiod. Explants from zygotic embryos were inoculated in MS medium containing different concentrations of BAP (0.0, 0.5, 1.0, 1.5, 2.0 or 2.5 mg L-1), with the cultures kept in a growth room at a temperature of 24.0 ± 2.0° C, under a photoperiod of 12 and 16 hours of light and a light intensity of 30 μmol m-2 s-1. At 21, 28, 35, 42 and 49 days after inoculation, the number of shoots per explant was evaluated. The treatment at the BAP concentration that gave the best multiplication rate (2.5 mg L-1) was set, and was tested in a further trial with different concentrations of NAA (0.0, 0.2, 0.4, 0 6, 0.8 or 1.0 mg L-1) under the same conditions as the previous experiment. The experimental designs were completely randomised, with five replications, and analysed in a 6 x 2 factorial. The data were submitted to analysis of variance and regression. No significant differences were seen in relation to the photoperiod or its interaction with the cytokinin and auxin under test. Multiplication was greater in the presence of 2.5 mg L-1 BAP, which gave a rate of 1.25 shoots/explant at 49 days of in vitro culture. The association of this BAP dosage with 1.0 mg L-1 NAA was even more efficient, producing 1.83 shoots per explant at 30 days of growth. The use of BAP together with NAA is beneficial to the induction of shoots in H. latispatha

Micropropagação de abacaxi ornamental (Ananas comosus var. bracteatus) por meio da indução ao estiolamento e regeneração de plântulas.

O mercado de flores tropicais está em franca expansão, sendo crescente a comercialização de abacaxi ornamental como flor de corte. Segmentos nodais estiolados são utilizados para a micropropagação em várias culturas. O objetivo deste trabalho foi avaliar a multiplicação in vitro de segmentos nodais estiolados para produção de mudas de abacaxi ornamental, Ananas comosus var. bracteatus. Talos, obtidos a partir de plântulas produzidas in vitro, foram inoculados em meio MS e mantidos no escuro, a 24 ± 1ºC. Os tratamentos foram: MS sem reguladores de crescimento; MS + 10mM de ANA; MS + 10mM de AIA e MS + 10mM de AIB. Ao final de 60 dias, avaliouse número de brotos/talo, número de nós/broto, comprimento do broto, comprimento médio dos internós e total de nós/talo. Não houve diferença no número de brotos estiolados por talo entre os tratamentos avaliados. O meio MS sem reguladores de crescimento apresentou o maior valor para o número de nós/broto como para o número total de nós/explante, diferindo estatisticamente dos meios contendo AIB e ANA para a primeira variável e AIA e ANA, para a segunda. Quanto ao comprimento do broto e o comprimento médio dos internós, os menores valores foram obtidos no meio contendo ANA. Para a regeneração de plântulas, foram utilizados segmentos nodais contendo dois nós, oriundos de talos estiolados in vitro por 60 dias no meio MS, sem regulador de crescimento, no escuro. Os tratamentos foram: MS sem reguladores de crescimento; MS + 4,44 mM de BAP; MS + 8,88 mM de BAP e MS + 13,32 mM de BAP. Os frascos foram incubados sob fotoperíodo de 16 horas, a 24 a ± 1ºC. Ao final de 30, 45 e 60 dias foi avaliado o número de plântulas obtidas por nó. Aos 30 dias, não houve diferença no número de plântulas/nó entre os tratamentos testados. Após 45 dias, 13,32 mM de BAP promoveu maior número de plântulas regeneradas por nó, que diferiu estatisticamente do meio sem a adição dessa citocinina. Aos 60 dias, esse mesmo meio proporcionou o maior número de plântulas por nó, diferindo estatisticamente do meio MS sem a adição de regulador de crescimento e do meio acrescido de BAP, na concentração de 4,44 mM

Use of paclobutrazol and ethylene in the potted production of ornamental pineapple

The expansion of residential areas has increased the demand for exotic and increasingly compact landscape plants. In this context, this work aimed to evaluate the effects of paclobutrazol (PBZ) and the timing of ethylene application on growth reduction and flowering anticipation in ornamental pineapples grown in pots. The randomized block design was used with factorial arrangement (2 x 5) and 4 replications and 4 plants per plot. The primary treatments are the presence and absence of PBZ. The secondary treatments were five times of floral induction with ethylene: 90; 120; 150; 180; 210 days after transplanting (DAT) the seedlings into the pots. It was evaluated the variables: height ratio between the heights of the pot and the plant; rosette diameter; leaves length ‘D’ and flowering index. At 255 DAT, although the plants did not respond to floral induction with ethylene, only those treated with PBZ were more compact and had different characteristics such as smaller size and a ratio below 1/3 of the height of the vase in relation to the plant that to favor its commercialization, in pot

Growth regulators in the induction of calli in anthers of the Goldex hybrid yellow melon

The melon is of socio-economic importance, especially in the north-east of Brazil. Obtaining homozygous lines has been an obstacle in breeding programs. In vitro androgenesis is one alternative, requiring the development of protocols for anther culture. The aim of this work was to study the effect of auxins and cytokinins on callus induction in anthers of the Goldex hybrid yellow melon. Two experiments were conducted in a completely randomised design, with 25 replications. In the first experiment, in a 3 x 3 factorial scheme, the treatments comprised concentrations of 6-furfurylaminopurine - KIN (0.0, 3.0 and 6.0 mg L-1) and indolylacetic acid - IAA (0.0, 3.0 and 6.0 mg L-1), added to Murashige and Skoog (MS) medium. In the second experiment, six treatments were tested: MS with no growth regulator; MS + 0.20 mg L-1 6-benzylaminopurine (BAP); MS + 0.20 mg L-1 naphthaleneacetic acid (NAA); MS + 0.45 mg L-1 2,4-dichlorophenoxyacetic acid (2,4-D); MS + 0.20 mg L-1 BAP + 0.20 mg L-1 NAA; and MS + 0.20 mg L-1 BAP + 0.45 mg L-1 2,4-D. The following were evaluated 60 days after anther inoculation: induction percentage, oxidation intensity, colour, texture, and the area and fresh weight of the callus. The auxins (IAA, NAA and 2,4-D) and cytokinins (KIN and BAP) induce callogenesis in anthers, but only in combination, the most suitable being 0.20 mg L-1 BAP + 0.45 mg L-1 2,4-D. The calli have a beige colour, friable texture and medium oxidation, with a strong association between the fresh weight and the area