Débora Costa Bastos

Estiolamento, incisão na base da estaca e uso do ácido indolbutírico na propagação da caramboleira por estacas lenhosas

Objetivou-se, neste trabalho, avaliar o efeito do estiolamento, da incisao na base da estaca e do tratamento com acido indolbutirico (AIB) no enraizamento de estacas lenhosas de caramboleira. As estacas foram padronizadas com um par de folhas inteiras e 12 cm de comprimento. O experimento foi conduzido em delineamento estatistico inteiramente casualizado, em arranjo fatorial 3 x 4, onde os fatores estudados foram tecnicas aplicadas nas estacas (estiolamento, ferimento na base e controle) e diferentes concentracoes de AIB (0; 3.000; 6.000 e 9.000 mg L-1). As estacas lenhosas foram utilizadas como tratamento-controle. O estiolamento foi realizado 45 dias antes da retirada da estaca no ramo, envolvendo-se a base da futura estaca com fita plastica preta. A incisao na base da estaca foi realizada no preparo das mesmas, atraves de dois cortes na base. As estacas foram mantidas em câmara de nebulizacao intermitente e, apos 75 dias, avaliaram-se as porcentagens de estacas enraizadas, de estacas vivas, de formacao de calos e o numero de raizes emitidas por estaca. Concluiu-se que as tecnicas de estiolamento e ferimento na base da estaca, e a aplicacao de AIB nao induziram a formacao de raizes em estacas lenhosas de caramboleira.

Cultivo in vitro de Sequoia sempervirens L. em meio de nutritivo esterilizado com hipoclorito de sódio

The autoclaving used for sterilization of glassware, culture media and surgical materials in laboratory is a costly operation, due to the high cost of the equipment and the equally high consumption of energy. For these reasons, the substitution of this sterilization technique for another less costly one, such as chemical sterilization, would be highly desirable. The present study aimed to compare the techniques of sterilization of plant tissue culture media with sodium hypochlorite and that of autoclaving, in Sequoia sempervirens culture, in order to develop a less costly technique in the sterilization of glassware and nutrient media for plant tissue culture. In the trial with Sequoia sempervirens , the concentrations of sodium hypochlorite added to the culture media were (w/v): 0% (autoclaved); B) 0.002%; C) 0.003%; D) 0.004% and E) 0% (without autoclaving). It was observed that the concentrations equal to or higher than 0.003% of total chlorine added to the nutrient media resulted in complete sterilization, as well as in plants with larger numbers and shoots lengths.

Diferentes substratos na produção de porta-enxertos de caramboleira

The aim of the present research was to verify the influence of different substrates in seedling production of star fruit tree rootstocks. Seeds were taken from ripe fruits of sweet star fruit, washed in tap water and sowed in polystyrene trays (72 cells with volume capacity of 120 cm3/cell), containing the following substrates: vermiculite, Plantmax®, Rendmax®, soil, sand, and sand + soil mixture (1:1, 2:1 and 1:2 v/v). After that, the trays were placed inside a lath house covered by 50 % brightness shade, and manually watered daily. After 130 days of sowing, the following biometric data were collected: percentage of live plants, length of sprouts and roots, and number of leaves. It was concluded that the mixture soil + sand (1:1 v/v) was most efficient in seed germination and early formation of star fruit rootstocks.

Influência da idade biológica da planta matriz e do tipo de estaca caulinar de caramboleira na formaçâo de raízes adventicias

Commercially, the most used method in the star fruit (Averrhoa carambola L.) propagation is the grafting, that may be accomplished by budding or cleft grafting. However, this method presents some characteristics that may turn the plantlets production onerous, demanding professional work and larger costs when compared with cutting methods. This paper was carried out with the aim of verifying the influence of the types of cuttings (top and median) and biological age (juvenile and adult) in the capacity of formation of adventitious roots in star fruits cuttings. Star fruits herbaceous cuttings were collected from juvenile branches (1 year) and adults (15 years), padronized with two leaves and 12 cm of length. Later the cuttings were placed in polyethylene trays containing vermiculite as substrate, in intermittent mist chamber with 50% of shading. The experimental design was completely randomized, with the factorial 2 x 2, where the studied factors were types of cuttings (top and median) and biological age of cuttings (juvenile and adult). After 70 days, the rooting, survival and sprouts percentage and number of roots emitted by cutting were evaluated. None of the variables analyzed were affected by the type of cuttings. One concluded that star fruits juvenile cuttings showed to be more efficient in the formation of adventitious roots (47%) when compared with the cuttings collected from plants with adult biological age.