Qualidade de bulbos de cebola em consequência de tratamentos pré-colheita Onion bulb quality due to pre-harvest treatments

Com o objetivo de se avaliar o efeito de tratamentos pré-colheita na qualidade de bulbos de cebola, através dos parâmetros perda de peso, espessura e coloração da casca, diâmetro e firmeza do bulbo, foi conduzido experimento em Paulínia, Estado de São Paulo, em 1997. Foram utilizados quatro tratamentos: testemunha; oxicloreto de cobre (250 g 100 L-1 de água); ácido bórico (250 g 100 L-1 de água); e a combinação dos dois últimos e seis cultivares: Serrana, Régia, Crioula e três híbridos da SVS, HT, HS-1 e HS-2. Os tratamentos foram aplicados durante a bulbificação. Os bulbos foram armazenados à temperatura ambiente (25ºC) e analisados periodicamente para os parâmetros citados. Os resultados permitiram observar que a aplicação pré-colheita do oxicloreto de cobre, nas quatro últimas semanas do ciclo, aumentou significativamente a resistência da casca dos bulbos, reduziu a perda de peso e incrementou a coloração dos mesmos, para todas as cultivares. Cultivares com casca mais escura apresentaram melhor resposta aos tratamentos pré-colheita para a coloração, do que as de casca mais clara. A firmeza dos bulbos, não foi influenciada pelos tratamentos pré-colheita.<br>Pre-harvest treatments were evaluated to enhance onion bulb quality in different onion cultivars adapted to tropical conditions. Parameters used were weight loss, skin color and thickness, bulb and firmness. Trials were carried out in 1997. Four treatments were used: control, copper oxicloride (250 g 100 L-1); boric acid (250 g 100 L-1), and a combination of the two chemical treatments (250 g 100 L-1 of each). Treatments were applied at bulbing stage. The six cultivars were Serrana, Régia, Crioula, and the hybrids HT, HS-1 and HS-2. Bulbs were stored at room temperature prior to evaluations. Results showed that copper oxicloride (250 g 100 L-1) induced an increase in skin thickness, decreased weight loss and enhanced color in cultivars. Dark skin cultivars had a better response to pre-harvest treatments in relation to light skin cultivars. Firmness was not affected by pre-harvest treatments

Produtividade de cebola influenciada pela aplicação de micronutrientes Onion yield influenced by micronutrient application

A aplicação excessiva de fertilizantes, o uso de corretivos da acidez sem critérios técnicos adequados e o monocultivo são práticas comuns na região cebolicultora catarinense, e isso tem contribuído para o aparecimento de sintomas visuais de deficiências nutricionais, principalmente de micronutrientes. O presente trabalho objetivou avaliar o efeito da aplicação de B, Zn e Mn na produtividade e na conservação de bulbos de cebola. Foram conduzidos três experimentos independentes, em campo, sendo um para cada nutriente, no município de Ituporanga, SC, de 2006 a 2009. Em cada experimento, os tratamentos consistiram de aplicações do micronutriente ao solo e de pulverizações foliares. As doses aplicadas ao solo variaram de 0 a 4 kg ha-1 para Zn, de 0 a 4,4 kg ha-1 para B e de 0 a 15,6 kg ha-1 para Mn. As pulverizações foliares, em número de seis a cada ano, foram realizadas a cada 14 dias, nas concentrações de 0,5 % de sulfato de zinco, de 0,25 % de ácido bórico e de 1,0 % de sulfato de manganês. A aplicação de Zn ao solo aumentou a produtividade de bulbos nas três safras, cujos incrementos variaram de 10 a 14,5 %. A dose de Zn que proporcionou a máxima produtividade de bulbos variou de 2,7 kg ha-1, na safra 2006/2007, para uma produtividade de 22,3 t ha-1, até a quantidade estimada de 4,5 kg ha-1, na safra 2008/2009, para produtividade de 35,6 t ha-1. A aplicação de Mn e de B, independentemente do modo de aplicação, e as pulverizações foliares com Zn não influenciaram a produtividade de cebola em nenhuma safra. A qualidade dos bulbos, avaliada por meio da ausência de deterioração durante 145 dias de armazenamento, não foi influenciada pela adição de Zn, B ou Mn. Assim, é importante aplicar Zn para a produção de bulbos de cebola em Cambissolos catarinenses, mesmo naqueles em que o teor desse nutriente no solo esteja acima do nível crítico considerado para os solos da região, provavelmente, em função da exigência da cultura.<br>The excessive use of fertilizers and liming as well as monoculture is rather common in the onion-producing region of Santa Catarina State, Brazil. Such practices have resulted in visual symptoms of micronutrient deficiency, mainly of micronutrients. This study aimed to measure the effect of B, Zn and Mn fertilizers on yield and quality of onion bulbs. Three individual trials, one for each nutrient, were carried out in the field, in Ituporanga, southern Brazil, from 2006 until 2009. In each experiment, treatments consisted of increasing rates of each micronutrient applied to the soil before planting and also of a single rate sprayed onto the leaves six times per season. Rates applied to the soil varied from 0 to 4 kg ha-1 for Zn, from 0 to 4.4 kg ha-1 for B, and from 0 to 15.6 kg ha-1 for Mn. The spray solutions contained zinc sulfate, boric acid and manganese sulfate, at concentrations of 0.5, 0.25 and 1.0 %, respectively. The application of Mn or B, regardless of the form, and Zn sprays, had no effect on onion yield in any growing season. The application of Zn to the soil increased onion yield in all three years, by 10-14.5 %. Maximum yield was obtained with Zn rates of 2.7 kg ha-1 in 2006/2007 (22.3 t ha-1), up to an estimated quantity of 4.5 kg ha-1 in 2008/2009 (35.6 t ha-1). The bulb quality was not affected by micronutrient application (Mn, B, or Zn), regardless of the form. It is therefore important to apply Zn to the soil for onion production in the State of Santa Catarina, even where Zn concentration exceeds the critical level established for the region, which is probably due to the requirement of this crop

Physiological and biochemical characterization of the assai palm (Euterpe oleracea Mart.) during seed germination and seedling growth under aerobic and anaerobic conditions

Physiological and biochemical aspects of assai palm during seed germination and early seedling growth were investigated. Seeds collected from plants growing in flooded and upland forests were used to determine the influence of normoxic (aerobic) and anoxic (anaerobic) conditions in germination and the initial and average time of development in the roots and shoots. After 75 days, seedlings germinated under normoxia were transferred to trays and submitted to flooding. Seed reserves (lipids, proteins, soluble sugars and starch) were monitored for quiescent and germinated seeds maintained under normoxic and anoxic conditions, as well as after 5, 10 and 20 days of seedling growth. Alcohol dehydrogenase (ADH) activity was quantified in roots and leaves of seedlings without or with flooding (partial and total). Seeds were not able to germinate under anoxia. Different strategies of storage mobilization of lipids, proteins, soluble sugars and starch were observed in seeds of each environment. ADH activity was induced by anoxia, with the highest level observed in the leaves. This study showed that, under normoxic conditions, the best developmental performance of assai palm seeds, from flooded or upland forest areas, during germination was associated with primary metabolites mobilization and seedling flooding tolerance with increased ADH activity. We conclude that the assai palm is well adapted to the anoxic conditions provoked by flooding