Antônio da Silva Souza

Micropropagation and in vitro conservation of Neoglaziovia variegata (Arr. Cam.) mez, a fiber producing bromeliad from Brazil

Neoglaziovia variegata (Arr. Cam.) Mez is a Bromeliaceae native to the Caatinga, used for fiber extraction in the Northeast Region of Brazil. The antropic activity has place this species among the threatened ones. The objective of the work was to establish an in vitro propagation and conservation of caroa. Seeds were cultivated in MS medium in the presence or absence of light. In vitro germinated seedlings were multiplied in MS medium supplemented with the combinations 0.05 and 0.50 µM NAA and 2.2 and 4.4 µM BAP and KIN. The best percentages of germination were obtained with the seeds incubated in the presence of light. The highest multiplication ratio was obtained for the NAA (0,5 µM) + BAP (4,4 µM) treatment and the number of roots, with NAA (0.5 µM) + KIN (2.2 µM). Plant acclimatization presented differentiated results regarding the substrates tested. The conservation was established.

Adequação de nutrientes do meio MT para o cultivo de embriões imaturos de tangerineira 'Cleópatra'

The objective of the present work was to adjust the macronutrient, micronutrient and vitamin concentrations of the Murashige & Tucker (MT) culture medium in order to promote the germination of ´Cleopatra´ Tangerine immature embryos, smaller than 3 mm. Seeds from fruits, 4 to 5 months after anthesis, in which the embryos do not germinate in recently indicated culture media for citrus, were used. Initially, the embryos were cultivated in basic culture medium containing sucrose and agar, followed by a sequence of steps, carrying out the adjustments of the normal concentration of macronutrients (1/1, ½ and ¼), micronutrients (1/1, ½, ¼ and 1/1, 3/2, 2/1) and vitamins (2/1, 1/1 e ½) of the MT medium. The experimental design was completely randomized in factorial scheme 3 (concentrations of MT) x 4 (embryo size), with 10 repetitions. The following variables were evaluated thirty days after embryo inoculation in culture medium: percentage of germination, percentage of normal plantlets and plantlet length. The best results were obtained using half the normal concentration of macronutrients, whereas the concentrations of micronutrients and vitamins remained unaltered.

Meio de cultura e tipo de explante no estabelecimento in vitro de espécies de maracujazeiro

Brazil is one of the main centers of genetic variability dispersion of the Passiflora genera. Its self incompatibility as well as disease incidence in its leaves and root system and, deforestation and monocultivation, promote loss of genetic material. Considering the risk of genetic erosion, the conservation of the variability in germplasm banks, which is of great interest in plant breeding, is necessary. Studies regarding the type of explant and concentration of the culture media are necessary in order to determine protocols of establishment and in vitro conservation of passion-fruit germplasm. The objective of the present work was to evaluate the influence of the salt and nutrient concentration in the MS culture medium and types of explants in the establishment and growth of the Passion fruit species: Passiflora giberti N. E.Brown, P. edulis Sims and P. laurifolia L. Each Passiflora species presented its own characteristics regarding in vitro development. The complete MS medium and nodal segments the second axilliary bud promoted better development of the genotypes studied.

Morphogenetic response of cotyledon and leaf explants of melon (Cucumis melo L.) cv. Amarillo Oro

Callus cultures from cotyledon and leaf explants of a Spanish cultivar of melon (Amarillo Oro) were tested for growth and morphogenic capacity on several culture media with different concentrations of IAA (indole-3-acetic acid) in combination with 1.0 mg.L-1 BA (6-benzylaminopurine) or 6.0 mg.L-1 KIN (kinetin). The best results were achieved with cotyledon explants. The leaf explants presented low bud formation capacity. Variability of organogenic response on cotyledons of different age (7, 5, 3 and 1-day-old) was evaluated. The age of explant had a significant influence on bud induction. Cotyledon explants from 7-day-old seedlings showed higher organogenic index and development of shoots when cultured onto MS medium supplemented with 1.5 mg.L-1 of IAA and 1.0 mg.L-1 of BA. The effect of cut type of cotyledonary explants on organogenic response was also investigated. Explants cut transversally showed the best results. The addition of copper sulfate in the culture medium promoted a qualitative improvement of the regenerated shoots.

Efeito da sacarose e sorbitol na conservação in vitro de Passiflora giberti N. E. Brown

This work objectified the study of sucrose and sorbitol effect in the in vitro conservation for Passiflora giberti N. E. Brown, access. Therefore, an experiment was conducted in a completely randomized design to compare control treatment (standard MS) to MS medium supplemented with three sucrose concentrations (0, 15 and 30 g L-1) combined with three sorbitol concentrations (10, 20 and 40 g L-1), in a total of 10 treatments with 20 replicas. The experiment evaluation was carried out at 30, 60, 90 and 120 days of incubation, whereas the height of shoots (cm), number of roots, number and color of leaves were observed. The results showed the possibility to maintain passion-fruit microplants for a four months period under slow growth in MS medium supplemented with 10 or 20 g L-1 of sorbitol, without sucrose, and kept under 16 hours photoperiod (22 µ E m-2 s-1) and temperature of 27 ± 1o C. Sucrose sustained the longest development of the microplants. Root formation was affected by the sorbitol in the concentration of 40 g L-1 and by the absence of sucrose in the culture medium.

In vitro regeneration and morphogenesis of somatic embryos of cassava

Este trabalho teve como objetivo estudar a embriogenese somatica e a regeneracao de plantas da variedade Cigana Preta a partir de apices caulinares e folhas imaturas obtidos de plantas cultivadas in vitro. Para a inducao de embrioes, os explantes foram cultivados em meio Murashige e Skoog (MS) suplementados com acido 2,4 diclorofenoxiacetico (2,4-D) ou 4-amino-3,5,6-trichloropicolinic acid (Picloram), ambos nas concentracoes 8,0 e 12 mg L-1. O desenvolvimento dos embrioes obtidos foi testado por dois meios de cultura com diferentes concentracoes de benzilaminopurina (BAP) (D1 ou D2). Embrioes em estagio cotiledonar foram incubados em meio de germinacao, constituido de sais e vitaminas do MS, 2,0 µM de sulfato de cobre, 2,4 g L-1 de Phytagel®, e 1,77 µM BAP. A maior frequencia de calos e numeros de embrioes por explantes foi obtida com 8,0 mg L-1 da auxina Picloram. As plantas regeneradas, oriundas do tratamento com Picloram apresentaram desenvolvimento normal e num periodo minimo de quatro semanas foram transferidas para meio de multiplicacao. Cortes histologicos de embrioes malformados, provenientes dos explantes foliares cultivados em 2,4-D revelaram que as estruturas cotiledonares tem origens independentes da formacao do meristema apical caulinar e nao houve formacao do meristema apical caulinar nos embrioes, sendo a maioria classificado como corneta. Este trabalho demonstrou que em mandioca o uso de diferentes auxinas proporciona diferentes condicoes para a formacao de embrioes somaticos e que a baixa conversao em plantas foi decorrente de anormalidades desses embrioes.

Somatic embryogenesis of Neoglaziovia variegata (Arruda) Mez, an important source of fiber from native Brazilian bromeliads

Neoglaziovia variegata (Arruda) Mez, a Bromeliad endemic to the Brazilian Caatinga and source of fiber for many different products, is considered an endangered species. Leaf and stem segments were cultivated on Murashige and Skoog (MS) medium with combinations of 2,4- dichlorophenoxyacetic acid (2,4-D) (0, 9, 18 and 27 µM) and glutamine (0, 50, 100, 150, 200 mg L-1) for the induction of embryogenic calli. Leaf segments did not present a favorable response for the combinations analyzed. The best response for embryogenic calli frequency with the best distribution of somatic embryos on the surface and better conversion rate was obtained using the stems explants in the medium containing 18 µM 2,4-D and 100 mg L-1 glutamine. The embryogenic calli obtained from the different induction media were transferred to MS medium supplemented with 30 g.L-1 sucrose, 2.4 g.L-1 Phytagel®, 0.53 µM α-naphthalene acetic acid (NAA) and 0.88 µM of 6-benzylaminopurine (BAP). The regenerated plants presented normal growth; however, many embryos did not fully develop.

Residual effect of growth regulators in etiolation and regeneration of in vitro pineapple plants

This work aimed to evaluate the influence of naphthaleneacetic acid (NAA) and gibberellic acid (GA3) plant regulators in in vitro etiolation and subsequent regeneration of the PE x SC-60 pineapple hybrid. Nodal segments of in vitro plants with approximately 5-7 cm height were incubated in basic MS culture medium supplemented with 0.0; 0.5 and 1.0 mg L-1 of naphthaleneacetic acid (NAA) in combination with gibberellic acid (GA3) in concentrations of 0.0; 0.5 and 1.0 mg L-1, and maintained at 27 oC under dark condition. Evaluations were carried out at 90 and 180 days after incubation period. The best results for length of etiolated stems were obtained with 1.0 mg L-1 of NAA. In the experiment followed by the regeneration, stems with 3 cm from the etiolation treatment, were cultivated in proliferation medium and the number of regenerated plants per treatment was evaluated at 60 days of cultivation. The treatment that promoted the best etiolation of plants also promoted the worst regeneration rates, demonstrating the residual effect of the auxin used in the previous step in the regeneration of plants of the pineapple hybrid evaluated.

CARACTERIZAÇÃO DAS APLICAÇÕES DE CRÉDITO RURAL E DOS FINANCIAMENTOS À PECUÁRIA LEITEIRA NA REGIÃO OESTE DO ESTADO DO PARÁ

SUMMARY: The article evaluates the profile of rural credit with emphasis on dairy farming financing in the municipalities of the western region of the state of Para. The data were collected from secure sources of the Brazilian financial system and field survey including 176 farmers from the Municipalities Itaituba, Ruropolis, Trairao and Placas. The results showed that the farmers’ level of access to rural financing has shown strong instability during the last two decades. During recent years a predisposition to new investments in dairy farming has been observed due to new commercialization opportunities and an increase in the number of dairy products. For the next few years, it is recommended that funds from rural credit be directed toward investments in genetic improvement of the dairy herds, pasture management, mechanization and milking hygiene, in order to aggregate value and quality to the milk supplied to the market.

Enraizamento de inhame em meios MS e carvão ativado

Yam microshoots were grown in : half the concentrations of salts and vitamins of the MS medium (1/2 MS) + 0 g L -1 of activated charcoal (AC), 1⁄2 MS + 0.5 g L -1 AC, 1⁄2 MS + 1.0 g L -1 AC, MS + 0 g L -1 AC, MS + 0.5 g L -1 AC, and MS + 1.0 g L -1 AC. The effect of the culture medium was significant only at concentrations of 0 and 1 g of activated charcoal for plant height. The differences in culture medium concentration and doses of activated charcoal caused no significant differences in the number of roots formed in yam plants growing in vitro. But the medium 1⁄2 MS + 1.0 g L -1 AC was more favorable for root development. It was concluded that for a better development of shoots and roots of yam plants it is recommended the use of half the concentration of salts and vitamins of the MS medium and that the greatest number of roots occurs in a medium supplemented with activated charcoal. Additional keywords: Dioscorea rotundata; microshoots; micropropagation.