Franscinely Aparecida de Assis

Efeito do silício na preferência para oviposição de Bemisia tabaci biótipo B (Genn.) (Hemiptera: Aleyrodidae) em plantas de feijão (Phaseolus vulgaris L.)

O biotipo B de Bemisia tabaci destaca-se entre as pragas principais do feijoeiro. Neste trabalho, objetivou-se avaliar a inducao de resistencia a mosca-branca pela aplicacao de silicio em feijoeiro. Foram testados 4 tratamentos, em esquema fatorial 2 (cultivares Carioca e Valente) x 2 (com e sem aplicacao de silicio) e 6 repeticoes. Dez dias apos a emergencia das plântulas, foram aplicados 500 ml de solucao de acido silicico a 1% no solo, na dosagem equivalente a 2 t SiO2/ha. Dez dias apos a aplicacao do silicio, as plantas foram infestadas com adultos nao sexados de mosca-branca em sala climatizada, sendo 100 moscas-brancas/vaso. Para o teste sem chance de escolha, o mesmo procedimento foi utilizado, com cada vaso coberto por gaiolas de tecido organza. Anteriormente a infestacao, uma planta de cada vaso foi retirada, seca em estufa ate peso constante para avaliacao do teor de fenois. Apos 48 horas de infestacao, os adultos liberados foram removidos das plantas para avaliacao do numero de ovos. Para isso, foi escolhida uma folha de uma planta/vaso, selecionando-se a terceira folha apical inteiramente desenvolvida. Apos quinze dias, foi avaliado o numero de ninfas de 3° e/ou 4° instar. Nao houve resposta entre cultivares de feijoeiro a aplicacao de silicio. Foi observado menor numero de ovos e menor numero de ninfas nas plantas tratadas com silicio no teste com chance de escolha. No teste sem chance de escolha, a aplicacao de silicio nao afetou a oviposicao da mosca-branca e o desenvolvimento das ninfas, bem como o teor de fenois.

Concentrações de sais do meio Knudson C e de ácido giberélico no crescimento in vitro de plântulas de orquídea

The aim of this research was to test different concentrations of culture medium Knudson C and gibberellic acid in the in vitro growth of Hadrolaelia lobatta x Hadrolaelia purpurata Aco and Cattleya loddigesii plantlets. Seedlings deriving from in vitro germinated seeds with approximately 1,0cm length, were inoculated in bottles of 250cm3 containing 60mL of Knudson C culture medium at salts concentrations of 0; 50; 100 e 200%, and supplemented with 0; 2.5; 5; 7.5; 10mg L-1 of GA3. The cultures were maintained in growth room with a 35µmolm-2s-1 irradiance, 16 hours photoperiod and 25±1°C of temperature. After 90 days, it is observed that the culture medium Knudson C 200% for Cattleya loddigesii promote better in vitro growth. The addition of GA3 (2.5mg L-1) is efficient in the number of leaves increment. Better in vitro multiplication is registered in Knudson C medium in the original concentration (100%). For Hadrolaelia lobatta x Hadrolaelia purpurata Aco, the concentration of Knudson C culture medium influences the number of leaves (salts 200%) and sprouts (salts 50%), but does not have effect in the growth and biomass. No effect of the GA3 in number of sprouts, length of aerial part and fresh mass for the two genotypes was verified.

Efeitos da terra diatomácea sobre Diabrotica speciosa (Germar, 1824) (Coleoptera: Chrysomelidae) em batata inglesa

A especie Diabrotica speciosa e um crisomelideo responsavel por causar danos consideraveis a batateira, o que torna indispensavel seu controle com inseticidas para minimizar os prejuizos causados a cultura. Assim, objetivou-se, com este trabalho, avaliar os efeitos da terra diatomacea sobre o comportamento alimentar e a mortalidade de D. speciosa em batata inglesa em condicoes de laboratorio. Adotou-se o DIC com tres tratamentos e oito repeticoes, sendo: 1 - testemunha; 2 - TD polvilhada (0,5 g/vaso) e 3 - TD pulverizada a 1%. As batateiras, cv. Emeraude, foram polvilhadas ou pulverizadas com TD, 30 dias apos o plantio e, 24 horas apos a aplicacao, as plantas foram fornecidas aos insetos, sem e com chance de escolha. Houve diferenca significativa entre os tratamentos, sendo a menor porcentagem de foliolos com injurias observada em plantas que receberam a aplicacao de TD pulverizada (teste sem chance de escolha) e TD polvilhada ou pulverizada (teste com chance de escolha). Tambem houve reducao do numero de injurias foliares as 24 e as 48 horas (TD polvilhada ou pulverizada) e, as 72 horas, a reducao foi observada somente com a aplicacao da TD polvilhada. Com relacao a acao inseticida da TD, foi verificado seu efeito apos 48 horas, tanto via polvilhamento, quanto via pulverizacao. Assim, a aplicacao de TD pode auxiliar no manejo de D. speciosa, contribuindo para conferir protecao as plantas de batata inglesa e aumentar a mortalidade desse inseto-praga.

Leaf miner incidence in coffee plants under different drip irrigation regimes and planting densities

O objetivo deste trabalho foi avaliar o efeito de diferentes regimes de irrigacao por gotejamento e densidades de plantio na incidencia do bicho‑mineiro, Leucoptera coffeella, em cafeeiro arabica, ao longo de um ano. O experimento foi realizado em 2008, em delineamento de blocos ao acaso, em parcelas subdivididas no tempo, com quatro repeticoes. Os tratamentos consistiram de quatro regimes de irrigacao por gotejamento – balanco hidrico climatologico, irrigacoes com base nas tensoes de 20 e 60 kPa, e uma testemunha nao irrigada –, os quais foram distribuidos em tres densidades de plantio: 2.500, 5.000 e 10.000 plantas por hectare. As avaliacoes foram realizadas mensalmente entre janeiro e dezembro de 2008. O maior periodo de ocorrencia da praga foi registrado de agosto a novembro, epoca de baixa umidade relativa do ar antecedida por periodo de estiagem. Cafeeiros irrigados apresentaram incidencia de minas intactas 2,2 vezes menor do que as plantas nao irrigadas. A irrigacao e o aumento da densidade de plantio contribuem para a reducao da incidencia do bicho‑mineiro do cafeeiro.

Modificações morfoanatômicas e fisiológicas de maracujazeiro fertilizado com silício

The objective of this work was to evaluate the effect of silicon fertilization on gas exchange, leaf anatomy, and ultrastructural characteristics of passion fruit (Passiflora edulis). The treatments comprised four concentrations of silicon (0, 0.28, 0.55, and 0.83 g per pot) at 1% silicic acid solution (SiO2.XH2O). This solution was applied around the stems of the plants. The first application was made 15 days after seedlings were transplanted. In total, three applications were made at 15-day intervals. The pots that constituted the control treatment received water in the same amount. After the final application, the plants were subjected to analyses of gas exchange, anatomical changes, and ultrastructural characteristics. The use of silicon promotes anatomical changes in passion fruit seedlings, such as increased adaxial epidermis thickness, reduced palisade parenchyma, and increased polar diameter/equatorial diameter ratio, which is related to stomata functionality. The concentrations of 0.55 and 0.83 g silicon per pot provide higher rates of photosynthesis, of transpiration, and stomatal conductance. The concentration of 0.83 g silicon per pot results in the greatest deposition of silicon in the abaxial epidermis of leaf surface.

Antioxidants in the control of microorganism contamination and phenol oxidation in Eugenia pyriformis

Uvaia (Eugenia pyriformis) is a fruit tree of the Myrtaceae family. It has recalcitrant seeds of limited longevity, making seed propagation difficult. Micropropagation is an alternative method to obtain a large quantity of progeny plants in a short period of time, by using any part of the plant as explant. The high concentration of phenols associated with the chemical composition of the Myrtaceae, and the presence of microorganisms in the plant material or culture media, can make in vitro propagation difficult and/or impossible. The objective was to evaluate various concentrations of antioxidants affecting the control of microbial contamination and phenol oxidation in vitro in uvaia. A completely randomized design was used, with a 3 (antioxidants PVP, L-cysteine, and ascorbic acid) × 3 (antioxidant concentrations 100, 200, and 300 mg L) × 2 (activated charcoal at 0 and 2 g L) factorial arrangement + 2 additional variables (absence of antioxidants and activated charcoal; absence of antioxidants with 2 g L activated charcoal), with three repetitions comprising four plants each. The percentage of bacterial and fungal contaminations, along with the number of oxidized explants, was evaluated after 7, 14 and 21 days of in vitro cultivation. It was concluded that, where bacterial and fungal contaminations were concerned, in vitro cultivation of uvaia can be performed without the use of antioxidants. PVP or ascorbic acid must, however be used in the process, at a concentration of 300 mg L, along with 2 g L of activated charcoal. This helps to minimize phenol oxidation.

Efeito de concentrações de glicina e inositol no cultivo in vitro de duas frutíferas de clima temperado

Aiming to improve the in vitro cultivation techniques of two temperate fruit i.e. blackberry cv. Tupy and grapevine rootstock cv. Kobber 5BB, different glycine and inositol concentrations in the culture medium were tested. The culture medium was constituted of MS basal medium, added of 30 g L-1 sucrose and 7 g L-1 agar, and the pH adjusted to 5.8 before the sterilization of 121oC and 1 atm for 20 minutes, and DSD1 basal medium for grapevine rootstock cv. Kobber 5BB, added of 20 g L-1 sucrose and 7 g L-1 agar, and the pH adjusted to 6.4. The work with blackberry consisted of 5 different concentrations of glycine (0; 1.0; 2.0; 4.0 and 8.0 mg L-1), 5 of inositol (0; 500; 100; 200 and 400 mg L-1) and its combinations. The work with grapevine composed of 4 different concentrations of glycine (0; 1.0; 2.0 and 4.0 mg L-1), 4 of inositol (0; 10; 20 and 40 mg L-1), and its combinations. Nodal segments from in vitro plants was excised and introduced into test tubes containing 15 mL of culture medium. After that, the culture tubes were transferred in a growth room to 25 ± 2oC, irradiance of 32 mol m-2.s-1 and photoperiod of 16 hours. The experiments were settled in a completely randomized design, using twelve explants per treatment. After 70 days of in vitro cultivation, better results for the blackberry cv. Tupy were obtained with glycine concentration as recommended in the MS culture medium (2 mg L-1) and 4 fold of the inositol value. For the grapevine rootstock, better results were obtained in the absence and/or with low glycine concentrations and the same or higher inositol concentration as recommended in the DSD1 culture medium.