Francisco José de Seixas Santos

Índices fisiológicos e de crescimento de um porta-enxerto de aceroleira sob estresse salino

Na literatura ha registros de variacoes na fisiologia e no desenvolvimento de genotipos diversos em condicoes de estresse salino. Nao se encontrando informacoes nesse sentido, sobre aceroleira, conduziu-se este trabalho com o objetivo de se avaliar os efeitos da salinidade sobre o clone BV1, atraves de variaveis fisiologicas e de crescimento, na fase de formacao de porta-enxerto. Os estudos foram realizados no Campo Experimental de Pacajus (EMBRAPA), na cidade de Pacajus, CE, testando-se seis niveis de salinidade da agua de irrigacao (condutividade eletrica, variando de 0,5 a 5,5 dS m-1), preparada mantendo-se a proporcao 7:2:1 entre Na:Ca:Mg, respectivamente. O sistema radicular da aceroleira e mais sensivel a salinidade que a parte aerea, assim como a fitomassa seca total quando comparada com a area foliar. A eficiencia da aceroleira em produzir materia nova por unidade de materia preexistente, aumenta com a elevacao do nivel de salinidade da agua de irrigacao. A velocidade de crescimento e a fotossintese liquida da aceroleira decrescem com o aumento do estresse salino.

Germinação, formação de porta-enxertos e enxertia de cajueiro anão precoce, sob estresse salino

With the purpose of evaluating effects of salinity of the irrigation water in different genotypes of precocious dwarf cashew, an experiment was conducted in greenhouse at the Experimental Station of Pacajus, belonging to Embrapa Tropical Agroindustria in the State of Ceara. The treatments in randomized block design consisted of six levels of electrical conductivity of water (ECw: 0.5; 1.5; 2.5; 3.5; 4.5 and 5.5 dS m-1) and two types of seedlings (CCP06 and CCP1001) with four replications, totaling 48 units each consisting of 54 plants. The irrigation waters were prepared maintaining a proportion of 7:2:1 for the ions Na:Ca:Mg. The effects of the salinity were evaluated on germination, germination period, number of leaves, plant height, stem diameter and total dry weight 25 and 40 days after planting; the plantlings were evaluated 30 days after grafting. With the exception of germination percentage, other variables were found to be affected negatively by salinity of the irrigation water and between clones the growth of CCP1001 was affected more adversely.

Policultivo coom diferentes espécies frutíferas de valor econômico

Resultados preliminares de um experimento, em execucao desde setembro de 2000 no Campo Experimental de Pacajus, CE, para avaliar um sistema de policultivo com fruteiras, sao relacionados e discutidos neste trabalho. Dez especies foram plantadas em uma area de 1,2 ha, em covas alternadas e divergentes em relacao as linhas laterais, sendo que cada planta de uma especie foi circundada por plantas de outras especies. Apos 15 meses, as especies bananeira, mamoeiro e goiabeira foram substituidas por cupuacuzeiro, pupunheira e abacateiro, respectivamente. A nao adaptacao da bananeira pode ter como causa os efeitos danosos dos ventos e maior irradiacao solar, devido ao maior espacamento utilizado no sistema em relacao ao cultivo comercial. A mangueira, o sapotizeiro, o cajueiro, a aceroleira e a gravioleira estao com bom desenvolvimento. E, com excecao da mangueira e do sapotizeiro, todas ja estao em frutificacao. Nos 34 meses de avaliacao, verificou-se que a recomposicao natural da flora entre as fileiras foi prejudicada pela carencia de nutrientes quimicos e materia orgânica do solo, o que pode ter favorecido, tambem, o ataque de pragas e doencas.

Efeito de bactérias diazotróficas na produção de abacaxizeiro 'Cayenne Champac', sob irrigação, em dois níveis de adubação nitrogenada

The objective of this work was to evaluate the effect of diazotrophic bacteria on yield of pineapple cv. Cayenne Champac (Champaka), under irrigation, with two levels of N fertilization. Treatments consisted of two N levels (180 kg and 300 kg ha-1 year-1), on the plots, and micropropagated plantlets inoculated with bacteria related to Burkholderia cepacia AB213, with Asaia bogorensis AB219 and without bacterial inoculation, on the subplots, using three replications. The bacterial inoculation was performed in a laboratory (with 108 bacterial cells plant-1) and the plant acclimatization in a glass house. After five months, they were transferred onto field, using 0.9 m between the lines and 0.3 m between the plants. The cultivar presented good performance under irrigation on the sandy soil in Pacajus, Ceara State, when fertilized with the highest N level. For each kilogram of the element the fresh mass of fruits grew by 124.3 kg ha-1, for the fertilizer levels. Plants inoculated with AB219 produced bigger fruits and 19.4% and 17.3% heavier when compared to fresh mass of fruits without and with crown from the controls on higher N level. The lower contribution of AB213 isolate was observed, and the fresh mass of fruits with crown ranged up to 9.9% on lower N level. The diazotrophic bacterial contribution on pineapple cv. Cayenne Champac was demonstrated with this work..

Características morfogênicas e estruturais de Megathyrsus maximus cv. Tanzânia-1 sob intensidades de desfolhação.

O efeito de intensidades de desfolhacao (20, 30, 40 e 50 cm acima do solo) sobre a producao de forragem e caracteristicas morfogenicas e estruturais de Megathyrsus maximus cv. Tanzânia-1 foi avaliado nos cerrados de Roraima.

Produtividade de forragem, composição química e morfogênese de Megathyrsus maximus cv. Mombaça sob períodos de descanso

The effects of rest periods (14, 21, 28, 35, 42 and 49 days) on green dry matter (GDM) yield, chemical composition and morphogenetic and structural characteristics of Megathyrsus maximus cv. Mombaça were evaluated under natural field conditions. GDM yields and regrowth increased consistently with highest rest periods. The leaf appearance and leaf expansion rates are inversely proportional to the rest periods, occurring the inverse for average leaf length, leaf area index and foliar senescence rate. Maximum GDM yields, regrowth yields, number of leaves tiller, average leaf length and leaf area index were obtained with rest periods at 36.4; 39.2; 40.8; 39.6 and 41.3 days. These data suggest that grass grazing at 35 to 42 days of rest period were optimal for obtain maximum yields and regrowth of rich forage.

In vitro effects of Pilocarpus microphyllus extracts and pilocarpine hydrochloride on Rhipicephalus (Boophilus) microplus.

The aim of this study was to assess the activity of aqueous (AE) and ethanolic extracts (EE) and pilocarpine hydrochloride, which were extracted and isolated from Pilocarpus microphyllus (Jaborandi), respectively, on Rhipicephalus (Boophilus) microplus. High performance liquid chromatography (HPLC) was performed to quantify these compounds. Larval packet and adult immersion tests were conducted with different concentrations. Five AE and EE concentrations, ranging from 6.2 to 100.0 mg mL-1, and six concentrations of pilocarpine hydrochloride, ranging from 0.7 to 24.0 mg mL-1, were tested. The lethal concentration (LC50) of each extract for larvae and engorged females was calculated through Probit analysis. The concentration of pilocarpine hydrochloride obtained from the EE and the AE was 1.3 and 0.3% (m/m), respectively. Pilocarpine hydrochloride presented the highest acaricidal activity on larvae (LC50 2.6 mg mL-1) and engorged females (LC50 11.8 mg mL-1) of R.(B.) microplus, followed by the EE which presented LC50 of 56.4 and 15.9 mg mL-1, for larvae and engorged females, respectively. Such results indicate that pilocarpine hydrochloride has acaricidal activity, and may be the primary compound responsible for this activity by P. microphyllus EE.

Acúmulo de forragem e morfogênese de Brachiaria ruziziensis sob níveis de desfolhação

The effect of defoliation levels (10, 15, 20, 25 and 30 cm above soil level) on green dry matter (GDM) yield and morphogenetic and structural characteristics of Brachiaria ruziziensis were evaluated under field conditions in Roraima ́s savannas. The effects of defoliation levels on the GDM yields, number of leaves plant, leaf area index, leaf appearance and elongation rates were quadratics and maximum values recorded with cutting at 22.2; 17.7; 22.5; 17.1 and 25.2 cm above soil level, respectively. The population tiller density was inversely proportional to the level of defoliation, while the opposite occurred for to medium blade length and leaf senescence rate. Apical meristem removing percentage was higher with increasing defoliation level. Aftermath regrowth showed close negative correlation with defoliation level.

EFICIÊNCIA DO NITROGENIO, PRODUÇAO DE FORRAGEM E MORFOGÊNESE DO CAPIM-MASSAI SOB ADUBAÇÃO

O efeito da adubacao nitrogenada (0, 40, 80, 120 e 160 mg de N/kg solo) sobre a producao e composicao quimica da forragem e caracteristicas morfogenicas e estruturais de Panicum maximum cv. Massai foi avaliado em condicoes de casa-de-vegetacao. O delineamento experimental foi em blocos casualizados com tres repeticoes. A adubacao nitrogenada afetou positiva e linearmente a producao de materia seca. As maiores taxas de aparecimento e de expansao foliar, o maior numero de folhas/perfilho, numero de perfilhos/planta e o tamanho medio de folhas foram obtidos, respectivamente, com a aplicacao de 155,6; 157,8; 147,0; 150,9 e 151,1 mg de N/kg solo. A eficiencia de utilizacao e a recuperacao aparente de N foram inversamente proporcionais as doses de N aplicadas.

Considerações sobre a utilização da monensina na nutrição de ruminantes

The ionophore monensin is the most widely used in ruminant nutrition as a way to increase the increment of protein of high biological value, by modifying and manipulating the rumen fermentation. The use of monensin has undergone changes and bans in several countries due to risk of poisoning when it is not properly used. However, when used correctly, can improve the performance productive of animals.