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Com o objetivo de avaliar a interferência das plantas daninhas sobre a produtividade e qualidade de cenoura (Daucus carota), foi realizado um experimento no período de julho a outubro de 2007, em Mossoró-RN. O delineamento experimental utilizado foi o de blocos casualizados, com seis tratamentos e quatro repetições. Os tratamentos consistiram de seis períodos de controle de plantas daninhas, em que a cultura da cenoura permaneceu livre da competição com essas plantas, por meio de capinas, a partir da emergência: 0-12, 0-24, 0-36, 0-48, 0-60 e 0-72 dias (testemunha mantida no limpo). As características avaliadas foram: produtividade comercial de raízes, teores de sólidos solúveis (SS), acidez total (AT), vitamina C e pH de raízes. A produtividade comercial de raízes de cenoura foi alterada pela convivência da cultura com as plantas daninhas, a qual respondeu a capinas até os 40 e 37 DAE, tolerando-se perdas de produtividade de 5 e 10%, respectivamente, em relação ao tratamento mantido no limpo durante todo o ciclo. Os teores de SS e de vitamina C não foram influenciados pela interferência das plantas daninhas, ao passo que a maior convivência da cultura com as plantas daninhas resultou em acidez total e pH das raízes mais elevados e menor relação sólidos solúveis/acidez total.

Complete factorial planning 2 was applied to identify the influence of the cassava starch(A), glycerol(B) and modified clay(C) content on the water vapor permeability(WVP) of the cassava starch films with the addition of bentonite clay as a filler, its surface was modified by ion exchange from cetyltrimethyl ammonium bromide. The films were characterized by X-ray diffraction(XRD), fourier transform by infrared radiation(FTIR), atomic force microscopy(AFM) and scanning electron microscopy(SEM). The factorial analysis suggested a mathematical model thats predicting the optimal condition of the minimization of WVP. The influence of each individual factor and interaction in the WVP was investigated by Pareto graph, response surface and the optimization was established by the desirability function. The sequence of the degree of statistical significance of the investigated effects on the WVP observed in the Pareto graph was C>B>A>BC>AC. Interactions AB, BC and AC showed that the modified clay was the factor of greater significance.

RESUMO Este trabalho teve como objetivo verificar a influência da época de colheita e do período de repouso dos frutos na qualidade fisiológica de sementes de mamão. Os frutos, produzidos no inverno e no verão, da cv Golden (0, 2, 4, 6, 8, 10 and 12 days) and after storage of the seeds for 30 days at 15ºC. The experimental design used was a completely randomized arrangement in 2x7x2 factorial scheme with four replications. The treatments of the factorial consisted of the combination of two fruit harvest times (September and January), eight rest periods of the fruits (0, 2, 4, 6, 8, 10 and 12 days) and two periods of evaluation of seed storage (0 and 30 days). There were variations in the humidity and dry matter of the seeds during the rest and harvesting of the fruits. The best vigour of the seeds occurred around 12 days of fruit rest, independent of seed storage. The rest period of the fruit contributed to increase the seeds germination, to the harvested fruits in January the maximum germination of the seeds was evident at the rest period inferior (9 to 12 days) to the fruits harvested in September (13 days).

The aim of this paper was to investigate the physicochemical characteristics and rheological behavior of some floral honeys from species of wild plants found in the Caatinga biome, as well as, correlate honey viscosities with its chemical composition.

A melancia é uma das culturas de maior expressão econômica para o Rio Grande do Norte, onde as condições edafoclimáticas são favoráveis ao seu cultivo. Técnicas de manejo de irrigação, adubação e fertirrigação estão sendo constantemente estudadas, visando ao aumento na sua produtividade. Neste sentido, a folha assume funções muito importantes na ABSTRACT RESUMOplanta, tais como interceptar e absorver luz e realizar fotossíntese, trocas gasosas e transpiração (Larcher 2000, Taiz & Zeiger 2004. A área foliar é um índice importante, em estudos de nutrição e crescimento vegetal, porque, além de afetar o acúmulo de matéria seca, fornece informações sobre o metabolismo vegetal, capacidade 1. Trabalho recebido em set./2011 e aceito para publicação em jun./2012 (n° registro: PAT 15764).

Quality of carrot roots under different population densitiesThis work was carried out from July to September, 2006, at the vegetable garden of UFERSA, in Mossoró, RN, Brazil, to evaluate the effect of different plant spacing on root quality of three cultivars of carrot. The experimental design was a complete randomized blocks, in a 6x3 factorial scheme, with three replications. The studied factors were spacing (20x4, 20x6, 20x8, 15x4, 15x6, and 15x8 cm) and cultivars (Brasília, Alvorada and Esplanada). The evaluated carrot root characteristics were: root length, root diameter, xylem length, xylem diameter, soluble solids content (SS), total sugar content (TS), total acidity, vitamin C, SS/TS ratio, and pH. The factors cultivar and plant spacing did not show interaction for any evaluated characteristic. Plant spacing influenced length and diameter of both root and xylem. Cultivar Alvorada had better performance for soluble solids and total sugar, as well as for SS/TS ratio.

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