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This study evaluated the diversity of cultivable plant growth-promoting (PGP) bacteria associated with apple trees cultivated under different crop management systems and their antagonistic ability against Colletotrichum gloeosporioides. Samples of roots and rhizospheric soil from apple trees cultivated in organic and conventional orchards in southern Brazil were collected, together with soil samples from an area never used for agriculture (native field). Bacteria were identified at the genus level by PCR-RFLP and partial sequencing of the 16S rRNA, and were evaluated for some PGP abilities. The most abundant bacterial genera identified were Enterobacter (27.7%), Pseudomonas (18.7%), Burkholderia (13.7%), and Rahnella (12.3%). Sixty-nine isolates presented some antagonist activity against C. gloeosporioides. In a greenhouse experiment, five days after exposure to C. gloeosporioides, an average of 30% of the leaf area of plants inoculated with isolate 89 (identified as Burkholderia sp.) were infected, whereas 60 to 73% of the leaf area of untreated plants was affected by fungal attack. Our results allowed us to infer how anthropogenic activity is affecting the bacterial communities in soil associated with apple tree crop systems, and to obtain an isolate that was able to delay the emergence of an important disease for this culture.

The banana (Musa spp. AAA) micropropagation shows a high incidence of off-types, among whose variegated plants are very common. Endogenous levels of growth regulators and pigment content were measured in normal and variegated leaves of the micropropagated banana plants growing in a greenhouse. Growth regulators were separated by high pressure liquid chromatography and submitted to enzyme-linked immunosorbent assay for quantification. Pigment content was measured using the colorimetric method. Green leaves contained 1.9 and 10 times more cytokinins compared with green and yellow sectors of variegated leaves, respectively. The levels of indoleacetic acid in normal leaves were significantly higher than those found in green and yellow sectors of variegated leaves; however, the levels of abscisic acid were lower in normal leaves. The lower content of chlorophylls in variegated leaves coincided with decreased endogenous levels of cytokinins, which indicated that variegation in banana leaves may be associated with alterations in the metabolism of this growth regulator.

Preliminary work on Passiflora alata leaves failed to detect harmane alkaloids using LC. The aim of this work was to investigate the production of harmane alkaloids through the cell culture of P. alata, inducing its precursor (Ltryptophan). The leaf explants presented satisfactory results after disinfection, and the callus formation was initiated in MS media with adequate quantities of phytohormones. Sixty days after inoculation, calli were inoculated in the optimized semi-solid MS media, with and without the addition of L-tryptophan (50, 100, 200 mg/L)

O Estado de Santa Catarina, apesar de conhecido pela forte economia industrial e agrícola, conta ainda com um mercado interno a ser abastecido. A horticultura ornamental possibilita a geração de empregos, de fixação do homem no campo e de fortalecimento de pequenos e médios produtores, podendo também ser utilizada em escala comercial. Com este objetivo, obteve-se um protocolo para a micropropagação de <i>Ananas bracteatus</i> (Shultz) cv. <i>striatus</i> Hort. Foram utilizadas gemas laterais do pseudocaule, como fonte de explantes. A assepsia dos explantes foi feita com etanol 70% (v/v), durante cinco segundos, seguida de imersão em NaOCl 1% (v/v), durante 15 minutos. Os explantes foram inoculados em meio MS líquido suplementado de 2,16 mM de ANA e 4,0 mM de BAP, durante 45 dias de cultivo. Meio MS líquido, suplementado com ANA (2,16 mM) e BAP (4,0 mM), resultou num melhor desenvolvimento dos explantes na fase de estabelecimento quando comparado com os meios sólidos. A presença isolada de BAP, nas fases de multiplicação (I, II e III), não foi eficiente para aumentar a taxa de multiplicação. A combinação de ANA (2,16 mM) e BAP (8,89 mM) foi necessária para se obter um maior número de brotos por explantes. A passagem dos explantes em mais de um cultivo, nas fases de multiplicação e de crescimento, teve como efeito o aparecimento de variantes somaclonais, originando plântulas verdes e albinas.

Nanism is one of the most frequent type of mutant in micropropagated banana plants from the Cavendish subgroup. The present study aimed at studying some of the hormone factors involved in this type of mutation. Rhizomes from normal and dwarf plants from the cultivar Grand Naine were incubated for 5 d in the presence of [3 H]-L-tryptophan, [ 3 H]-indole-3-acetic acid and gibberellin, to quantify the endogenous levels of indole-3-acetic acid-ester, indole-3-acetic acid-amide, free indole-3-acetic acid, and cytokinins. The endogenous levels of indole-3-acetic acid and its ester-and amide-conjugated forms were measured in normal and dwarf plants incubated for 30 d with gibberellin, indole-3-acetic acid, and L-and Dtryptophan. In normal plants, the use of [ 3 H]-L-tryptophan resulted in higher levels of radioactivity in the retention times corresponding to indole-3-acetic acid, indole-3-acetic acid-aspartate, indole-3-acetic acid-glycine and indole-3-acetic acid-alanine. These values were higher than those observed in dwarf plants. Higher quantities of radioactive indole-3-acetic acid and of amide-forms in dwarf plants occurred in rhizomes treated with [3 H]-L-tryptophan and gibberellin simultaneously. The endogenous levels of total cytokinins were the same in both materials, while the levels of indole-3-acetic acid in normal plants were 1.5 times higher than in dwarf plants. Moreover, in these ones application of tryptophan and gibberellin coincided in an increase in the levels of free indole-3-acetic acid in dwarf plants and to a decrease in the levels of indole-3-acetic acid-ester and indole-3-acetic acid-amide.Key words: indole-3-acetic acid metabolism, growth regulators, somaclonal variation. Metabolismo do ácido 3-indolil acético em plantas anãs e normais de bananeira micropropagada (Musa spp. AAA):O nanismo em plantas de bananeira micropropagada representa uma das formas mais comuns de alteração genética no subgrupo Cavendish. Utilizaram-se rizomas de plantas normais e anãs de bananeira cv. Grande Naine, incubados durante 5 dias na presença de [ 3 H]-L-triptofano (Trp), [ 3 H]-ácido 3-indolil acético e giberelina (GA 3 ), para o estudo da biossíntese de ácido 3-indolil acético e ácido 3-indolil acético amida e dos níveis endógenos de citocininas totais (Cks) e ácido 3-indolil acético livre. Os teores endógenos de ácido 3-indolil acético e de seus conjugados éster e amida foram obtidos de plantas anãs e normais incubadas durante 30 dias na presença de GA 3, ácido 3-indolil acético e L-e D-triptofano. A aplicação de [ 3 H]-L-triptofano resultou na obtenção de quantidades mais elevadas de radioatividade nas plantas normais, no tempo de retenção coincidente com o de ácido 3-indolil acético, ácido 3-indolil acético-aspartato, ácido 3-indolil acético-glicina e ácido 3-indolil acético-alanina, valores esses superiores aos observados nas plantas anãs. Verificou-se a ocorrência de maior quantidade de ácido 3-indolil acético radioativo e de forma amida nas plantas anãs nos rizomas tratados com [3 H]-L-triptofano e GA ...

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