Standard germination test in physic nut (Jatropha curcas L.) seeds

Abstract

-Defining adequate methods to assess seed germination is important to control the quality of commercial lots, especially for species that are not yet included in the Rules for Seed Testing. This study aimed to establish an adequate procedure for germination test in physic nut seeds (J. curcas L.). Three seed lots, in eight replications of 25 seeds each, were sown on paper towel rolls moistened with a water volume equivalent to 2.7 the weight of the dry paper and in sterilized sand moistened up to 60% of its water-holding capacity. The seeds of each treatment were maintained on germination chambers at temperatures of 20, 25, 30 and 20-30 o C. Daily counts were made to define the ideal date to perform the first and the last count test. Criteria for classifying seedlings as normal and abnormal were also established. The experiment was conducted in a completely randomized design in a split plot arrangement, and the means were compared by Tukey's test (P<0.05). For maximum germination potential of physic nut seeds, the germination test should be conducted at 25 o C and 30 o C, using sand or paper towel as a substrate, with the counts at 7 and 12 days after sowing.Index terms: viability, methodology, seeds, physic nut.Teste de germinação em sementes de pinhão manso (Jatropha curcas L.) RESUMO -Estabelecer procedimento adequado para a condução do teste de germinação com espécies que ainda não constam nas Regras para Análise de Sementes é de grande importância para viabilizar a certificação e comercialização de lotes. Objetivou-se estabelecer metodologia para a condução do teste de germinação em sementes de pinhão manso (J. curcas L.). Sementes de três lotes, em oito repetições de 25, foram semeadas nos seguintes substratos: rolo de papel toalha umedecido com volume de água equivalente a 2,7 vezes o peso do papel seco, confeccionando-se rolos; areia esterilizada e umedecida até 60% da sua capacidade de retenção (entre areia). As sementes foram mantidas em germinadores nas temperaturas de 20, 25, 30 °C e 20-30 ºC, realizando-se contagens diárias para definir a data ideal para as avaliações do teste. Foram estabelecidos também critérios para a classificação das plântulas como normais e anormais. O experimento foi conduzido em DIC, em esquema de parcela subdividida. As médias dos tratamentos foram comparadas pelo teste de Tukey (P<0,05). Para a obtenção do potencial máximo de germinação das sementes de pinhão manso, o teste de germinação deve ser conduzido nas temperaturas de 25 o C ou 30 o C, utilizando-se semeadura entre areia ou em rolo de papel, com contagens aos 7 e 12 dias após a semeadura.Termos para indexação: viabilidade, metodologia, sementes, pinhão manso.

&lt;i&gt;Jatropha curcas L&lt;/i&gt;. and &lt;i&gt;J. macrocarpa&lt;/i&gt; Griseb: Seed Morphology, Viability, Dormancy, Germination and Growth of Seedlings

“…However, the seed GP of J. curcas in the early stages of aging was higher than that found by Moncaleano-Scandon et al [23] and Oliveira et al [61]. On the other hand, at 96 h of aging treatment, the GP showed values similar to those determined by Oliveira et al [61].…”

Physiological changes in Jatropha curcas L. seeds during storage

“…The rolls were kept in a germination chamber at 25 °C. The evaluations were performed at seven and 12 days after sowing, and the results were expressed as a percentage of normal seedlings (Oliveira et al, 2014a).…”

“…after seven days. The results were expressed as a percentage of normal seedlings (Oliveira et al, 2014a).…”

Temperature and maturation stage: its effects on the germination of Jatropha seeds

“…No germination occurred at 20 ºC, regardless of the maturity stage, probably due to the fact that this temperature is lower than that recommended for species originating in tropical environments and adapted to high temperatures (Dias et al, 2012). At temperatures 25 and 30 ºC, satisfactory germination results were achieved with Stage III seeds, corroborating Oliveira et al (2014).…”