T. G. Junghans

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.

Lipoxygenase activities during development of root and nodule of soybean

The objective of this work was to evaluate root and nodule soybean lipoxygenases in Doko cultivar and in a near isogenic line lacking seed lipoxygenases, inoculated and uninoculated with Bradyrhizobium elkanii. The lipoxygenase activities from roots collected at 3, 5, 9, 13, 18 and 28 days post-inoculation and from nodules collected at 13, 18 and 28 days post-inoculation were measured. The pH-activity profiles from root and nodules suggested that the lipoxygenases pool expressed in these organs from Doko cultivar and triple-null near isogenic lines are similar. The root lipoxygenase activity of Doko and triple-null lines, inoculated and uninoculated, reduced over time. The highest lipoxygenase activity observed at the beginning of root formation suggests the involvement of this enzyme in growth and development of this organ. However, for nodules an expressive increase of lipoxygenase activity was noticed 28 days post-inoculation. Root and nodule showed, at least, two mobility groups for lipoxygenases in immunoblottings, with approximately 94 and 97 kDa.

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.

Estádio de maturação de frutos e influência de ácido giberélico na emergência e crescimento de Passiflora spp.

The aim of this work was to evaluate emergence and initial growth in plants of Passiflora spp. from seeds obtained from fruit at different stages of maturation and treated with different concentrations of gibberellic acid (GA3). The species under evaluation were Passiflora alata, P. cincinnata, P. setacea, P. edulis and P. gibertii. For the first trial, the seeds were extracted from fruits at different stages of maturation, and sown in polyethylene bags in a completely randomised design with a 4 x 3 factorial scheme (species x stage of maturation), with five replications. A second and third experiment evaluated respectively, seeds stored for 11 months and seeds collected from freshly picked fruit of the same species, immersed in a solution of GA3 (0, 250, 500 and 1000 mg L-1) and transferred to an agricultural substrate. The experimental design was of randomised blocks in a 5 x 4 factorial scheme (species x GA3 concentration), with four blocks and twenty-five seeds per lot to analyse emergence. In P. cincinnata, P. alata, P. edulis and P. setacea, fruit at the pre-ripe stage can be harvested with no harm to the physiological quality of the seeds. A solution of GA3 up to 1000 mg L-1 did not increase emergence or initial growth in plants of Passiflora spp. stored for 11 months. Seeds from ripe, freshly picked fruit of Passiflora spp. display greater and faster emergence, and greater initial plant growth after soaking in a 500 to 1,000 mg L-1 solution of GA3.