Renato Innecco

Alelopatia de extratos voláteis na germinação de sementes e no comprimento da raiz de alface

Abstract – The objective of this work was to identify allelopathic effects of volatile extracts of essential oils ongermination and radicle length of lettuce seedlings. Five concentrations were utilized for each oil (0.0, 0.001, 0.01,0.1 and 1.0%, v/v) arranged into a completely randomized design with four replicates of 25 seeds. The volatileextracts of essential oils of cinnamon, alecrim-pimenta, capim-citronela and alfavaca-cravo revealed allelopathicpotentialities on lettuce seed germination and radicle growth, effect which varied according to the oil concentration.The volatile extract of Jaborandi essential oil stimulates radicle growth and does not inhibit lettuce seedsgermination, which is characterized as a beneficial allelopathic effect.Index terms: Lactuca sativa, Cinnamomum zeylanicum, Lippia sidoides, Cymbopogon citratus, Ocimumgratissimum, Pilocarpus microphyllus. Introducao As plantas competem por luz, agua e nutrientes, re-velando uma concorrencia costante entre as especiesque vivem em comunidade. Essa concorrencia contri-bui para a sobrevivencia das especies no ecossistema, ealgumas desenvolvem mecanismos de defesa que se ba-seiam na sintese de determinados metabolitos secunda-rios, liberados no ambiente e que irao interferir em algu-ma etapa do ciclo de vida de uma outra planta (Sampietro,2001).A alelopatia pode ser definida como um processo peloqual produtos do metabolismo secundario de um deter-minado vegetal sao liberados, impedindo a germinacaoe o desenvolvimento de outras plantas relativamente pro-ximas (Soares, 2000). Os efeitos alelopaticos sao me-diados por substâncias que pertencem a diferentes ca-tegorias de compostos secundarios. Os recentes avan-cos na quimica de produtos naturais, por meio de meto-dos modernos de extracao, isolamento, purificacao eidentificacao, tem contribuido bastante para um maiorconhecimento desses compostos secundarios, os quaispodem ser agrupados de diversas formas (Ferreira &Aquila, 2000).A resistencia ou tolerância aos metabolitos secunda-rios e uma caracteristica especie-especifica, existindoaquelas mais sensiveis como Lactuca sativa L. (alfa-ce), Lycopersicon esculentum Miller (tomate) eCucumis sativus L. (pepino), consideradas plantasindicadoras de atividade alelopatica. Para que seja

Adubação orgânica e altura de corte da erva-cidreira brasileira

The effects of organic fertilization and cutting height on dry matter and essential oil production from leaves of Lippia alba, limonene-carvone chemotype, were evaluated in the Northeastern Brazilian Region. A split plot experiment was conducted with the organic fertilization (0; 2 and 4 kg m-2) as main plots and 15; 30 and 45 cm cutting height as subplots. First harvest was done 60 days and the second 120 days after planting date. Dry matter and essential oil production were not influenced by fertilization. Highest dry matter production was observed on 45 cm cutting height. Highest essential oil production was obtained on 30 and 45 cm cutting height.

Características do óleo essencial de capim-citronela em função de espaçamento, altura e época de corte

Citronella grass (Cymbopogon winterianum Jowitt.) has grown in importance due to an increasing demand of the essential oil. The influence of spacing (50 x 50; 50 x 80 e 80 x 80 cm), cutting height (15 and 30 cm above ground) and harvesting season (four, six and eight months after planting) on productivity and essential oil quality was evaluated. The study. occurred in field, in Pentecoste, Ceara State, Brazil, from September 2002 to September 2003. The treatments were organized in a factorial 3 x 3 x 2 scheme, in randomized block design, with three replicates. Cutting plants four months after planting date resulted in significantly higher essential oil production when cut at 30 cm height. Six months after planting date, higher yield was obtained at 15 cm height. The cutting height did not influence essential oil production when plants were harvested after eight months. Using larger plant spacing (80 x 80 cm) resulted in significantly higher essential oil production when plants were cut at 15 cm, divergent to the result observed with minor spacing (50 x 50 cm). The citronellol + citronellal content was significantly higher in plants cultivated at intermediate spacing and cut after six months at a height of 30 cm. The geraniol content, however, was higher in plants harvested after four months, with no influence of spacing or cutting height.

Germinação de sementes de Operculina macrocarpa (L.) Farwel e Operculina alata (Ham.) Urban

Due to changing cropping practices in perennial grass seed crops in western Oregon, USA, alternative rotation systems are being considered to reduce weed infestations. Information is generally lacking regarding the effects of alternative agronomic operations and herbicide inputs on soil weed seed bank composition during this transition. Six crop rotation systems were imposed in 1992 on a field that had historically produced monoculture perennial ryegrass (Lolium perenne L.) seeds. Each system plot was 20 x 30 m, arranged in a randomized complete block design, replicated four times. Twenty to thirty soil cores were sampled in June 1997 from each plot. The weed species composition of the cores was determined by successive greenhouse grow-out assays. In addition to seed density, heterogeneity indices for species evenness, richness, and diversityViable seeds of several native plant species present difficulties to germinate. Two trials were carried out to identify appropriate methodology to overcome seed dormancy in Operculina macrocarpa and Operculina alata. In the first one, the seeds of Operculata macrocarpa were submitted to the following treatments: dry cooling; wet heat; immersion in peroxide, immersion in hot water, immersion in sulfuric acid; wet cooling; mechanical scarification; soaking in potassium nitrate; and the control. Percentage of germination, hard seeds and dead seeds were determined. In the second trial, seeds of Operculina macrocarpa and Operculina alata were scarified and sown on paper and sand substrates and set to germinate under five different environmental conditions: continuous light and constant temperature (25oC), continuous light and alternating temperatures (20oC/16h-35oC/8h), continuous darkness and constant temperature, continuous darkness with alternating temperatures (20oC/16h-35oC/8h), and alternating light and temperatures (light/35oC/8h-darkness/20oC/16h). Percentage and time to germination were determined. Mechanical scarification was the most efficient method to break dormancy in Operculina macrocarpa; towel paper, temperature between 20-30oC and darkness were appropriate conditions for seed germination of Operculina macrocarpa and Operculina alata.

Propagação vegetativa da alfavaca-cravo utilizando diferentes tipos de estacas e substratos

Universidade Estadual Paulista Faculdade de Ciencias Agronomicas Departamento de Horticultura

CARACTERÍSTICAS FÍSICAS DE PEDÚNCULOS DE CAJUEIRO PARA COMERCIALIZAÇÃO IN NATURA

Nine clones of early dwarf cashew (Anacardium occidentale L. var. nanum) were evaluated within an experiment of clone competition under irrigation in Mossoro-RN, Brazil, with the objective of selecting cashew apples for fresh fruit market. Clone CCP 76 was used as a control. Cashews were harvested in august 1997 and evaluated for: firmness, size (upper and lower diameter and length), shape, color (color chart and pigment content) and weight (whole and apple). Only clone CCP 09 among those evaluated produced poorer coloring than control CCP 76, while in apples from clones CAP 6 (500), END 157, END 189 and END 329 the color was more intense than in control. Only clones END 157, END 183 and END 189 besides the control produced apples that can be classified as type 4 (highest commercial value), whilst only clones CAP 6 (500), END 157 and END 183 produced pear shaped apples. Clone END 157 presented the best characteristics for fresh fruit market even when compared to control. Results for clones END 183 and END 189 were similar to control, except for color in END 183 and shape in END 189.

Morfologia de sementes e plântulas de cártamos

The safflower (Carthamus tinctorius L.) belongs to the Compositae or Asteraceae family, nowadays, it is used to adornment. The objective of this experiment was to determinate the biometry, to describe and to illustrate the external morphology of the seed. The essay was conducted at the Laboratory of Analysis of Seeds of the Phytotechny Department, Center of Agricultural Sciences of the Federal University of Ceara State. It was calculated the weight of 1000-seeds and the water content of the seeds. It was made the individual measuring of the length, of the breadth and of the thickness to the biometric determinations and determined the morphologic characterization of their external parts. The 1000-seeds weight of this lot was 33.75 g and the water content was 8.6%. It was observed that the safflower seed is eurispermic, with the following dimensions: length equal to 6.84 mm, width equal to 4.21 mm and thickness equal to 3.37 mm. The germination is phanero-epigeal.

Micropropagação do jaborandi

The jaborandi (Pilocarpus microphyllus Stapf.) is a tree belonging to the Rutaceae family and is well known for its intensive use in the pharmaceutical industry through one of its most active principles, the pilocarpine, used to control glaucoma. The purpose of this research is to develop micropropagation protocols. Shoot tips and stem segments used in the micropropagation were removed from the seedlings grown in vitro and cultivated in MS medium with different concentrations and combinations of growth regulators. A treatment with 3% of NaOCl and the lack of GA3 caused a higher percentage of germination and a lower rate of contamination. The apical segment was the most efficient for shoot emission with best average length under different concentrations of BAP and different combinations of zeatin and kinetin.

Utilização do paclobutrazol, ethephon e nitrato de potássio na indução floral da mangueira no semi-árido nordestino

Com este trabalho objetivou-se verificar o comportamento produtivo da cultura da manga, cultivar Tommy Atkins, com uso do paclobutrazol, nitrato de potassio e ethephon, conduzida em plantios comerciais da MAISA (Mossoro Agroindustrial Sociedade Anonima). O experimento foi desenvolvido no ano de 1999 em delineamento experimental de blocos casualizados, no esquema fatorial 3x2x3; 3 doses de Paclobutrazol: 0 mg.L-1 1000 mg.L-1 e 1500 mg.L-1; 2 concentracoes de nitrato de potassio: 3 e 4%; 3 dosagens de ethephon: 0 mL.L-1; 0,50 mL.L-1 e 1,0 mL.L-1; com 4 repeticoes. O paclobutrazol na dosagem de 1500 mg.L-1 foi a que mais reduziu o crescimento das plantas. Esse produto apresentou-se como um bom inibidor de crescimento e teve boas respostas no rendimento da mangueira cultivar Tommy Atkins. O KNO3 e o ethephon, isoladamente, nao influenciaram em nenhuma das caracteristicas avaliadas.

Qualidade de cajus-de-mesa obtidos nos sistemas de produção integrada e convencional

The cashew tree (Anacardium occidentale L.) is a plant of great importance for the Brazilian Northeast Region, due to the diversity of products generated for the fruit and peduncle and the amount of generated jobs. Despite this, there is no standardization in the cropping systems presently used, with negative consequences in the yield and quality of the raw material for consumption and for industry. The conversion of traditional orchards to the integrated fruit production systems will contribute to minimize this scenery. The objective of this work was to compare the integrated fruit production (IFP) and conventional cropping production (CP) systems in dwarf cashew orchard, as to apple quality. The experiment was installed in a commercial orchard, located in Beberibe Country, State of Ceara, Brazil, in an area of 1.0 hectare, where the IFP and CP systems had been developed. Each system had occupied 0.5 hectare, separated by five crop lines of plants. In the IFP system, cropping practices were applied according to the Legal Marks of Integrated Fruit Production in Brazil. In CP system, cropping practices were applied accordingly with common used by local growers. Apple color, firmness, soluble solids (SS), titratable acidity (TA), vitamin C content and pH were evaluated. For these variables, means were estimated from twelve samples obtained in both treatments, which were compared by test t (P<0.05). For the TA and vitamin C content variable, the IFP system was significantly superior to the CP ones. For the pH variable, a significant difference was observed between the averages of the systems, being the value gotten in the CP superior to the one of the IFP. The cashew apples obtained in the IFP system showed better quality. The post-harvest quality of the cashew apples had been influenced by the production systems.