pH exudate test as a method to estimate viability and vigor of Citrus limonia Osbeck seeds

Abstract

-The pH exudate is a quick test used to check the seed membranes integrity; however, its performance is limited due to the singularity of each specie requiring adjustments about its methodology. In this sense, the aim of this study was to perform a quick and accurate physiological potential estimation of Citrus limonia Osb. ('Rangpur Lime') seeds through pH exudate test. First, there was carried out the characterization of five seedlots of 'Rangpur Lime' by determination of the thousand seed mass, water content, germination and emergence. Then, a complete randomized experimental design was installed in a factorial scheme: 5 × 3 × 2 (five seedlots, three indicator solutions, and two immersion periods), to evaluate the pH exudate. The seeds were individually distributed in polypropylene trays, and after the immersion periods, there were taken pictures and analyzed by a numeric scale. Despite the similarity, the emergence test showed to be more efficient for 'Rangpur Lime' seeds comparing to the germination test, because it promoted higher percentage of seedlings. Regarding the pH exudate test, there were not observed differences between the seedlots for both analysis, visual and image, not being efficient to discriminate lots of 'Rangpur Lime'.Index terms: 'Rangpur Lime', propagation, quick tests, seed quality.Teste do pH do exsudato como método para estimar a viabilidade e o vigor de sementes de Citrus limonia Osbeck RESUMO -O pH do exsudato é um teste rápido utilizado para verificar a integridade das membranas de sementes, porém seu desempenho é limitado devido à singularidade de cada espécie necessitando de ajustes sobre sua metodologia. O objetivo deste estudo foi realizar uma estimativa rápida e precisa do potencial fisiológico de sementes de Citrus limonia Osb. ('Limão Cravo') pelo teste pH do exsudato. Inicialmente, realizou-se a caracterização de cinco lotes de sementes de 'Limão Cravo' pela determinação da massa de mil sementes, teor de água, germinação e emergência. Posteriormente, foi instalado um delineamento inteiramente casualizado em esquema fatorial: 5 × 3 × 2 (cinco lotes de sementes, três concentrações de solução indicadora e dois períodos de imersão), para avaliar o pH do exudato. As sementes foram distribuídas individualmente em bandejas de polipropileno e, após os períodos de imersão, foram fotografadas e analisadas por meio de escala numérica. Apesar da similaridade, o teste de emergência mostrou ser mais eficiente para sementes de 'Limão Cravo' comparado ao teste de germinação, pois promoveu maior percentual de plântulas. Em relação ao teste pH do exsudato, não foi possível observar diferenças entre lotes de semente para ambas análises, visual e de imagem, não sendo um teste eficiente para discriminar lotes de 'Limão Cravo'.Termos para indexação: 'Limão Cravo', propagação, testes rápidos, qualidade de semente.1

Viability and vigor of Moringa oleifera Lam. seeds by means of rapid tests

“…Adjusting its methodology for each species is essential to obtain successful results. The pH of exudate is a biochemical method that is based on the chemical reactions that occur in the process of membrane deterioration, causing a reduction in seed viability, in addition to being a fast and low-cost test (Carvalho et al, 2018). Thus, it makes it possible to classify the lots, identify seeds with inadequate performance in the fi eld, and determine the level of viability (Wendt et al, 2017).…”

“…The p H of exudate test is based on the amount of solutes released between viable and non-viable seeds subjected to soaking, whose viability is related to deterioration events, such as membrane permeability and leaching of solutes (Carvalho et al, 2018). This test proved to be efficient in evaluating the viability of seeds of 'araucaria' (Araucaria angustifolia Bertol.)…”

Temperature on Annona cherimola Mill. x Annona squamosa L. seed germination

“…Thus, germination will only take place within determined temperature limits, which includes temperature or a temperature range, where the process occurs with maximum efficiency (Carvalho and Nakagawa 2012). Although, seeds of many species germinate at constant temperatures (Lima et al, 2011;Carvalho et al, 2018a), others show a favorable germination reaction under alternating temperatures, probably an adaptation to temperature fluctuations during the daytime/nighttime periods, which occur in the nature (Copeland and Mcdonald 1995;Carvalho and Nakagawa 2012).…”