Luminosity, temperature, and substrates on the germination of Solanum capsicoides

Solanum capsicoides, commonly known as red soda apple, is a little-studied species with phytotherapeutic characteristics of interest to the pharmaceutical industry. However, little is known about its agronomic characteristics. Therefore, this study aimed to assess the effect of light, different temperatures, and substrates on the germination of S. capsicoides seeds. The study consisted of two experiments: Experiment I - Germination of S. capsicoides seeds under different wavelengths. The seeds were kept on Petri dishes covered with Germitest™ paper moistened with distilled water and exposed to the monochromatic, red, far-red, and dark wavelengths. The experiment was performed in a completely randomized design with four replications of 25 seeds. Experiment II - Germination of S. capsicoides seeds on different substrates and at different temperatures. The seeds were distributed according to six substrates: paper roll, on paper, between sand, on sand, on soil + sand + manure, and between soil + sand + manure. The seeds were also subjected to the constant temperatures of 20, 25, 30, and 35 °C and the alternate temperatures of 20-30, 20-35, 25-30, and 25-35 °C, characterizing a 6 x 8 factorial arrangement. Germination rate, germination speed index, and mean germination time were evaluated. Red soda apple seeds are classified as positive photoblastic, with the highest germination rate occurring at the temperature of 20-35 °C combined with on paper, paper roll, on sand, and between sand substrates.

Fitting nonlinear autoregressive models to describe coffee seed germination / Ajuste de modelos não lineares autorregressivos na descrição da germinação se sementes de café

Cumulative germination of coffee has a longitudinal behavior mathematically characterized by a sigmoidal model. In the seed germination evaluation, the study of the germination curve may contribute to better understanding of this process. The aim of this study was to evaluate the goodness of fit of Logistic and Gompertz models, with independent and first-order autoregressive errors structure, AR (1), in the description of coffee (Coffea arabica L.) line Catuai vermelho IAC 99 germination, at five different potential germination. The data used were from an experiment conducted in 2011 at the Seed Analysis Laboratory of the Federal University of Lavras. The Logistic and Gompertz nonlinear models were appropriately adjusted to the percentage germination data. The Gompertz model with first-order autoregressive errors structure was the best to describe the germination process.

A germinação acumulada de sementes de café tem um comportamento longitudinal matematicamente caracterizado por um modelo sigmoidal. Na avaliação de sementes, o estudo da curva de germinação pode contribuir para melhor entendimento de tal processo. O objetivo deste estudo foi avaliar a qualidade do ajuste dos modelos Logístico e Gompertz, com estrutura de erros independentes e autorregressivos de primeira ordem, AR(1), na descrição de germinação de sementes de café (Coffea arabica L.), linhagem Catuaí vermelho IAC 99, em cinco diferentes potenciais de germinação. Os dados utilizados foram provenientes de um experimento conduzido no ano de 2011 no Laboratório de Análises de Sementes da Universidade Federal de Lavras. Os modelos não lineares Logístico e Gompertz se ajustaram adequadamente aos dados de porcentagem de germinação acumulada. O modelo Gompertz com estrutura de erros autorregressivos de primeira ordem apresentou-se como o melhor para descrever o processo germinativo ao longo do tempo.