Maturation of seeds of Poincianella pluviosa (Caesalpinoideae)

Abstract

-The persistence of viable seeds in the soil is an important way to assure plant propagation, especially for species which produce seeds with short lifespan. Poincianella pluviosa is a tree species which seeds have short to medium storability at room temperature. The comprehension of the maturation process is crucial to understand its strategy for propagation and it could provide tools to improve seed viability in ex situ conditions. Flowers were tagged in two consecutive cycles of maturation and pods were periodically harvested until dispersion. Seeds were classified based on their morpho-physiological features, capability to germinate and develop seedlings. The complete maturation process was attained 315-330 days after anthesis, a period longer than reported for seed viability at room temperature. The maximum dry mass and seed vigor were reached at the end of maturation, although elevated seedling production was obtained before physiological maturity. We suggest that the precocious ability to produce seedlings in a long maturation could be a strategy to overcome environmental constraints, as the species is distributed in a wide range of phytogeographic domains in Brazil.Index terms: ex situ conservation, physiological maturity, seed shedding, seed maturation, sibipiruna. Maturação de sementes de Poincianella pluviosa (Caesalpinoideae)RESUMO -A manutenção de sementes viáveis no solo é uma forma importante para garantir a propagação, especialmente para espécies que produzem sementes de vida útil curta. Poincianella pluviosa é uma espécie arbórea cujas sementes apresentam curto a médio período de armazenamento em condições de laboratório. Assim, a compreensão do processo de maturação é fundamental para entender as estratégias de propagação da espécie, representando uma ferramenta para aprimorar a viabilidade das sementes em condições ex situ. As flores foram marcadas em dois ciclos de maturação consecutivos e os frutos foram colhidos até dispersão. As sementes foram classificadas de acordo com suas características morfofisiológicas e a capacidade de germinar e desenvolver plântulas. Observou-se que o processo completo de maturação (315-330 dias após antese) é maior do que o tempo descrito na literatura para manutenção da viabilidade destas sementes em temperatura ambiente. Valores máximos de massa seca e vigor foram alcançados no final da maturação, embora elevada produção de plântulas tenha sido obtida antes da maturidade fisiológica. Sugere-se que a capacidade precoce de produzir plântulas em um longo período de maturação poderia ser uma estratégia para superar limitações ambientais, já que a espécie está distribuída em diversos domínios fitogeográficos no Brasil.Termos para indexação: conservação ex situ, dispersão de sementes, maturação de sementes, maturidade fisiológica, sibipiruna.

Seed position and influences on Caesalpinia pulcherrima germination and reserve proteins

“…Lorenzetti et al (2018) observed in Caesalpinia peltophoroides that mature seeds presented 45% of PG, being that in the present work, all are above this value, thus inferring that they are ripe. However, Silva et al (2015) found that Caesalpinia pluviosa seeds at the physiological maturity point showed germination around 60%, with P3, P4 and P5 being above that, and P1 and P2 below. In the results of the proteins reserve (Table 2) it can be seen that the range of albumin found was 157.26 to 189.97 mg g -1 DM, and the P3, P4 and P5 presented the best values differing from P1 and P2, which presented the lowest results.…”

Seed germination in Ormosia macrocalyx , an endangered tropical forest tree

“…In addition, shorter germination times were recorded in scarified O. nitida seeds (7.8 days) (Lopes et al 2006) and O. arborea (11 days) (Marques et al 2004). Those results indicate that scarification is required to fracture the sclereid cells of the seed coats of Ormosia species in order to initiate germination, a common treatment for leguminous seeds that present deep dormancy due to the presence of a hard coating (Mantoan et al 2012, Freitas et al 2013, Silva et al, 2015. In the case of the control and the water soaking treatment, GI was delayed and initiation time was much longer than in the seeds with scarification treatments (Table 2).…”

“…In general terms, both fruit and seed must be mature: dryness is indicative of maturation and in this condition they respond favourably to germination (Srimathi et al 2013;Silva et al 2015); in the dehiscent fruits, this is followed by opening, which is an evolutionary characteristic that allows the dispersion of the seeds and occurs when these has dehydrated completely (McAtee et al 2013). In legumes, the process is accompanied by lignification of the fruit covers in order to avoid damaging the seeds with excess moisture and to allow them to maintain dormancy until environmental conditions are favorable (Smýkal et al 2014).…”

Reserve metabolism of stored and germinated Araucaria angustifolia seeds

“…The key part of biochemical evaluation for understanding the metabolism of recalcitrant seeds after harvest is to characterize the stage of seed development or "maturation degree" (Barbedo et al, 2013;Silva, Centeno, Ribeiro, & Barbedo, 2015;Lamarca et al, 2016). This characterization is very difficult since there is not a clear division between the processes of maturation and germination (Berjak & Pammenter, 2008;Walters, 2015).…”