Amaralina Celoto Guerrero

Análise de crescimento de gérbera de vaso conduzida em diferentes substratos

O cultivo e o comercio de gerbera em vaso sao recentes e ha uma grande demanda quanto a selecao de substratos adequados a sua producao. O presente trabalho foi desenvolvido com o objetivo de avaliar o crescimento de duas cultivares de gerbera de vaso, conduzidas com diferentes substratos. O experimento foi realizado em casa de vegetacao entre setembro e novembro de 2008, em Botucatu-SP. O delineamento experimental utilizado foi de blocos ao acaso em esquema fatorial 5x2 (substratos x cultivares) e quatro repeticoes. Plantas de gerbera, cultivares Cherry e Red, foram avaliadas quinzenalmente (1, 15, 29 e 43 dias apos aclimatacao (DAA)) quanto a area foliar e a fitomassa seca da parte aerea, as quais foram ajustadas em relacao ao tempo com o programa ANACRES para obtencao da razao da area foliar (RAF), taxa de crescimento relativo (TCR) e taxa de assimilacao liquida (TAL). As plantas de gerbera apresentaram melhor desenvolvimento quando conduzidas no substrato 4 (30% casca de pinus, 30% C1, 20% fibra de coco granulada, 20% fibra de coco mista). A selecao de substratos adequados ao desenvolvimento de gerbera deve considerar, principalmente, as caracteristicas quimicas e fisicas dos mesmos. Para as cultivares estudadas, valores de pH do substrato inferiores a 5,5 e superiores a 7,0 foram inadequados para o desenvolvimento, bem como densidades umidas superiores a 530 kg m-3.Cultivation and commercialization of potted gerbera are recent issues and there is a great demand for adequate substrates for its production. This work aimed to evaluate the growth of two potted gerbera cultivars (Cherry and Red) grown in different substrates. The experiment was carried out in a greenhouse from September to November 2008 at Botucatu, Sao Paulo State, Brazil. Experimental design was randomized blocks in a 5x2 factorial arrangement (substrates x cultivars). Gerbera plants leaf area and dry phytomass were evaluated fortnightly (1, 15, 29 and 43 days after acclimation (DAA)). For the leaf area ratio (RAF), relative growth rate (TCR) and net assimilation rate (TAL), the total dry phytomass and leaf area were adjusted in relation to time using the ANACRES program. The gerbera plants had better development in substrate 4 (30% pinus bark, 30% C1, 20% granulated coconut, 20% mixed coconut). The selection of substrates for the development of gerbera plants should consider primarily its physical and chemical attributes. For the studied cultivars, the substrate pH below 5.5 and above 7.0 was unsuitable for development as well as dry densities above 530 kg m-3.

Acúmulo de nutrientes em gérbera de vaso em função de fontes e doses de potássio

Gerbera is one of the several cultivated species of economic importance to agriculture. This is a plant with good durability, resistance to transport and high appreciation by consumers. However, despite the expansion of commercial production of flowers and ornamental plants, research has not grown at the same rate, especially with regard to nutrition and fertilization. The content and accumulation of macronutrients were evaluated in plants of gerbera in two growth stages (vegetative and reproductive), using different concentrations of potassium in the nutrient solution and two sources (chloride and silicate). The experiment was carried out in a greenhouse of the Universidade Estadual Paulista, Botucatu, Brazil. The experimental design was of randomized blocks, with a 2x5 factorial scheme, comprising two sources of potassium (silicate and chloride) with five concentrations (0, 50, 100, 150 and 200 mg L-1 of potassium, in nutrient solution), four replications and five plants per plot. The gerbera cultivar used was Red, with dark center, for growing in vase. The levels of macronutrients (N, P, K, Ca, Mg and S) were accessed on leaves during the vegetative period and leaves and flowers (inflorescence + stem) on the end of the reproductive period. The accumulation was obtained through the multiplication of the nutrient content with the dry weight of the same ones and the total accumulation was obtained by the sum of accumulation on leaves and flowers (inflorescence + stem). Potassium silicate promoted greater content and accumulation of nutrients in leaves without a distinctive dose. The descending order for the absorption of nutrients of the gerbera plants was K>N>Ca>Mg>P>S for chloride and potassium silicate on the end of the vegetative and reproductive period for leaves and total accumulation. In the reproductive period the order of absorption was K>N>P>Ca>S>Mg for the both sources used.

Características dos substratos na absorção de nutrientes e na produção de gérbera de vaso

ABSTRACT Characteristics of substrates for nutrient absorption and production of gerbera The production systems on substrates have been employed in most commercial cultivation of flowers and ornamental plants, including gerbera. However, its introduction as potted flower is recent in Brazil and many studies, especially those related to the determination of substrates physical and chemical properties, which contribute to production quality are still needed. The present study aimed to assess the influence of substrates characteristics for nutrient absorption and production of potted gerbera. The experiment was carried out in greenhouse with the experimental design in randomized blocks, factorial arrangement 5x2 (5 substrates and 2 cultivars) and 4 replications. Treatments consisted of substrates with different physical and chemical characteristics and gerbera cultivars (Cherry and Red). Plants grown on substrate with pH above 7.0 had a reduction in iron absorption, resulting in lower intensity of green coloration in the leaves. Plants grown on substrate with pH below 5.0 showed toxic levels of manganese and lower dry mass. The characteristics of the substrate, especially the pH, influence the nutrients absorption and the production of potted gerbera, altering the final plant quality.

Absorção de nutrientes em cultivares de gérbera cultivada em vaso

The analysis of the uptake of nutrients is important for understanding the nutritional requirements of a cultivar during its development and identifies periods of increased demand, which allows scheduling fertigation. Nevertheless, the information is limited for gerbera. Thus, the present study was conducted to determine the uptake of potted gerbera cultivars Cherry and Red conducted in substrate in a crop cycle in the period August-October 2008. The experiment was carried out in a greenhouse in a randomized block split plot with four replications. The plots were composed by cultivars and subplots by dates of collection. During the development of the plants, the content and accumulation of macro and micronutrients was assessed in plant tissue of the shoots. The macronutrients were accumulated in the following order: K>N>Ca>Mg>P>S (524, 334, 119, 47, 42, 21 mg plant-1). The micronutrients were accumulated in the following order: Fe>Mn>B>Zn>Cu (7897, 1505, 801, 384,63 µg plant-1). The reproductive was the period of greatest uptake of nutrients, except for Fe.