4 research outputs found
In vitro propagation of purple pitahaya (Hylocereus costaricensis [F.A.C. Weber] Britton & Rose) cv. Cebra
Limitations to large-scale propagation of purple pitahaya (Hylocereus costaricensis [F.A.C. Weber] Britton & Rose), a potential source of betalains for the food industry, can be overcome through utilization of in vitro culture technologies. In this work, successful in vitro propagation from areoles of adult purple pitahaya plants is reported. Factors affecting culture initiation, bud sprouting and growth, shoot multiplication, rooting, and acclimatization were studied. Best results for culture initiation were obtained from the central region of new joints by disinfection of large (5–7 cm in length) explants that were subsequently divided. Explants were sequentially treated with Extran® alkaline detergent for 10 min, followed by immersion in 70 % (v/v) ethanol for 15–30 s, a mixture of the fungicide Benomyl and the bactericide Agrymicin (2 g l−1 each) for 30 min, and disinfection in sodium hypochlorite (1.0 % w/v) for 15 min. Culture of sectioned individual areoles, without removing thorns, on Murashige and Skoog medium supplemented with 15 or 30 μM N 6-benzylaminopurine (BAP) for 3 mo with monthly subcultures, followed by transfer to the same medium with reduced BAP (0–2 μM), induced bud sprouting in over 80 % of explants, adequate growth of the shoots, with production of lateral shoots, and spontaneous rooting within 160 d. These plants were successfully acclimatized in vermiculite and peat moss (1:1), or perlite and peat moss (2:1) in the greenhouse, with over 90 % survival rate. One hundred percent of the in vitro-derived plants were successfully transferred to the field. Furthermore, these plants showed higher survival rates, larger height and increase in stem diameter than equivalent plants from the same genotype, derived from stem segments (the common clonal propagation system utilized for this species) that were simultaneously planted.Universidad de Costa Rica/[734-A5-029]/UCR/Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Agroalimentarias::Centro para Investigaciones en Granos y Semillas (CIGRAS
Chemical synthesis and optical, structural, and surface characterization of InP-In2O3 quantum dots
Modelagem da recomendação de corretivos e fertilizantes para a cultura da soja Modeling lime and fertilizer recommendations for soybean
A recomendação de adubação para as culturas agrícolas, no Brasil, é feita com base em tabelas que relacionam a classe de disponibilidade do nutriente no solo com a dose a ser aplicada. Este trabalho apresenta uma alternativa para recomendar corretivos e fertilizantes para a cultura da soja, o SIRSo (sistema de recomendação de corretivos e fertilizantes para a cultura da soja). O princípio desse sistema é o balanço nutricional, ou seja, a recomendação se faz a partir da diferença entre o requerimento de nutrientes pela planta e o suprimento de nutrientes pelo solo, por resíduos orgânicos, por fertilizantes e pela calagem. O sistema considera ainda o fator sustentabilidade, visando manter uma quantidade de nutriente no solo capaz de garantir produtividade mínima em cultivos subseqüentes. Para recomendar calagem, o sistema considera dois métodos: a neutralização do Al3+ e a elevação dos teores de Ca2+ + Mg2+, ou a saturação por bases. O requerimento de nutrientes varia com a produtividade esperada de grãos, com as características do solo e com a taxa de recuperação pela planta do nutriente aplicado ao solo. O suprimento pelo solo depende da disponibilidade do nutriente, estimada a partir da análise de solo e da taxa de recuperação pelo extrator do nutriente aplicado. As comparações entre as recomendações geradas pelo SIRSo e aquelas oriundas das tabelas em uso no País mostram, em geral, que o SIRSo recomenda maior quantidade de nutrientes, principalmente de P e K quando consideradas as maiores produtividades, fato confirmado pela análise de sensibilidade, que mostrou grande variação da dose a ser recomendada desses nutrientes com a produtividade de grãos. Esse fato pode ser considerado como vantagem do SIRSo em relação às tabelas, muitas das quais apresentam pouca ou nenhuma variabilidade das doses em relação à produtividade.<br>Fertilizer recommendations for agricultural crops in Brazil are based on tables that relate indexes of nutrient availability in the soil with the required dose of the nutrient. This study presents an alternative for lime and fertilizer recommendations for soybean, called SIRSo. This lime and fertilizer recommendation system for soybean considers the nutritional balance, i.e., recommendations are based on the difference between plant nutrient requirement and the nutrient supply from the soil through organic residues, fertilizers and liming. The system further takes a sustainability factor into consideration, aiming at the maintenance of soil nutrient levels that ensure a desired minimum yield in subsequent cultivations. The system considers two methods for liming recommendations: Al3+ neutralization and increased Ca2+ + Mg2+ contents or base saturation. Nutrient requirements vary according to the expected grain yield, the soil characteristics and plant recovery rate of the nutrient applied to the soil. The soil supply depends on the estimated nutrient availability based on the soil analysis, and on the recovery rate of the applied nutrient by the extractor. Comparisons of SIRSo-based recommendations with those of the tables used nationwide show that SIRSo generally recommends higher nutrient quantities, mainly for P and K, when the highest yields are considered. This fact was confirmed by the sensitivity analysis, which detected wide variation of the recommended dose for these nutrients according to the grain yield. This fact is considered an advantage of SIRSo over the tables, where recommendations of doses according to the yield are little or not adjustable at all