Biometry and effect of temperature and of seeds size on the protrusion of cotyledonary petiole of carnauba

Abstract

Resumo -Objetivou-se avaliar a biometria das sementes de carnaúba e o efeito da temperatura e do tamanho das sementes na protrusão do pecíolo cotiledonar. Realizou-se a análise biométrica com uma amostra de 100 sementes, avaliandose comprimento e diâmetro, o que permitiu classificá-las em três classes de diâmetro. Utilizou-se o delineamento inteiramente casualizado em esquema fatorial 4 x 4: quatro tamanhos de sementes (pequena -Φ ≤ 12,42 mm, média -12,42 mm < Φ ≤ 14,24 mm, grande -Φ > 14,24 mm e mistura -sementes que não foram classificadas) e quatro temperaturas (20, 25 e 30 °C e temperatura ambiente -28,8 °C). Foram utilizadas quatro repetições de 25 sementes por tratamento e cada unidade experimental foi acondicionada em recipiente plástico com 250 mL de água e mantida sob as diferentes temperaturas, realizando-se contagens diárias das sementes que apresentavam a protrusão do pecíolo cotiledonar. Os resultados permitiram concluir que o comprimento e o diâmetro das sementes de carnaúba analisadas apresentam comportamento assimétrico à esquerda. Nas temperaturas de 20 e 25 ºC ocorre maior porcentagem de protrusão do pecíolo cotiledonar em todos os tamanhos de sementes, exceto para as grandes, que expressam melhor resultado apenas a 25 ºC. Sementes de tamanhos médio, grande e mistura apresentam maior velocidade de protrusão. A temperatura de 25 °C é a que proporciona maior velocidade de protrusão. Quando mantidas sob 20 ºC, as sementes de carnaúba demoram 32 dias para alcançar a máxima protrusão do pecíolo cotiledonar.Palavras-chave -Copernicia prunifera. Comprimento. Diâmetro. Embebição.Abstract -This work aimed to evaluate the biometry of carnauba seeds and the effect of temperature and seeds size on the protrusion of cotyledonary petiole. It was realized the biometric analysis with a sample of 100 seeds, evaluating length and diameter, what allowed to classify the seeds in three diameter classes. It was used a completely randomized design in a factorial arrangement 4 x 4: four seeds sizes (small -Φ < 12.42 mm, medium -12.42 mm < Φ < 14.24 mm, large -Φ > 14.24 mm and mixture -seeds that were not classified) and four temperatures (20, 25 and 30 °C and environmental temperature -28.8 °C). Were used four replications of 25 seeds per treatment and each experimental unit was packed in recipients containing 250 mL of water, maintained under different temperatures, realizing daily counting of the seeds that presented the protrusion of the cotyledonary petiole. The results allowed the conclusion that the length and the diameter of the carnauba seeds analyzed present an asymmetric behavior to the left. Under the temperatures of 20 and 25 ºC occurred the highest percentages of protrusion of cotyledonary petiole in all the seeds sizes, except for the large seeds, that expressed the best result only under 25 ºC. Seed of sizes medium, large and mixture presented highest protrusion speed. The temperature of 25 ºC is the one that promotes the highest protrusion speed. When maintained under 20 ºC, the seeds took 32 days to o...

Pre-germination Treatments, Quality of Light and Temperature on Syagrus coronata (Mart.) Becc. Seeds Germination

“…Temperatures that favor seed germination vary according to the species. For different palm tree species, the most adequate temperatures for germination have been determined, such as 25 °C for Copernica prunifera (Reis, Bezerra, Gonçalves, Pereira, & Freitas, 2010), 30 °C for Oenocarpus minor Mart. (Silva, Cesarino, Lima, Pantoja, & Môro, 2006) and 35 °C for Thrinax parviflora Swartz (Pivetta et al, 2005).…”

Germination response of palm seeds on a two-way thermogradient plate

“…Copernica prunifera (Reis et al, 2010), 30 °C for Oenocarpus minor (Silva et al, 2006) and Elaeis guineensis (Norsazwan et al, 2016), or 25-30 °C for Dypsis decaryi (Luz et al, 2008). Furthermore, close temperatures may even be applied before germination to overcome dormancy, as reported by Ferreira & Gentil (2017) for Phytelephas macrocarpa seeds maintained under 25 °C for nine months without losing viability.…”