Histochemical analysis of seed reserve mobilization in Passiflora edulis Sims fo. flavicarpa O. Deg. (yellow passion fruit) during germination

Abstract

In the present work, we analyzed the histochemical aspects of Passiflora edulis seeds reserve mobilization during the first ten days of germination. Our results showed that mainly lipids present in the endosperm are used as a reserve source, and their levels reduce at the same time the radicle protrudes, between the fourth and sixth day of sowing. Furthermore, protein bodies are present in the cotyledons, which are degraded as germination occurs and are almost depleted by the time of radicle protrusion. Starch grains also appear in the late germination period, and it is not clear if there is any reserve wall polysaccharide consumption in the endosperm.Keywords: seed germination, lipid bodies, protein globules, carbohydrates. Análise histoquímica da mobilização de reservas em sementes de Passiflora edulis Sims fo. flavicarpa O. Deg (maracujá amarelo) durante a germinação ResumoNo presente trabalho analisamos os aspectos histoquímicos da mobilização de reservas das sementes de Passiflora edulis, durante os primeiros dez dias de germinação. Nossos resultados mostraram que principalmente lipídios presentes no endosperma são utilizados como reserva, com o seu nível começando a diminuir ao mesmo tempo em que ocorre a protrusão da radícula, entre o quarto e sexto dia do início da embebição. Corpos proteicos também estão presentes nos cotilédones, e são degradados à medida que ocorre a germinação e são consumidos quase totalmente quando da protrusão da radícula. Grãos de amido também aparecem no período tardio de germinação, e não está claro se há ou não consumo de polissacarídeos de reserva de parede no endosperma.Palavras-chave: germinação de sementes, corpos lipídicos, glóbulos proteicos, carboidratos.

Cellular and molecular changes associated with competence acquisition during passion fruit somatic embryogenesis: ultrastructural characterization and analysis of SERK gene expression

“…Numerous oil bodies surrounding large protein bodies were identified as initial reserve sources in the cotyledon cells, consistent with the common pattern of reserve storage that has been described previously for Passiflora species (Corner 1976;Tozzi and Takaki 2011;Rocha et al 2012). These compounds may play an important role during in vitro morphogenesis.…”

“…These observations support the idea that reserve compounds are necessary for cellular reorganization and differentiation (Zienkiewicz et al 2011). Oil bodies are the main source of energy for the germination of P. edulis seeds (Tozzi and Takaki 2011), and consistent with our observations, oil bodies were previously shown to be associated with the glyoxysome, which is an organelle that is involved in cellular mechanisms of lipid body mobilization (Graham 2008). The phospholipids released via lipid metabolism can be promptly used for the synthesis of the different types of membranes and organelles that are characteristic of differentiated cells (Murphy 2001;van Meer et al 2008).…”

Histochemical evaluation of induction of somatic embryogenesis in Passiflora edulis Sims (Passifloraceae)

“…Proteins, lipids, and carbohydrates are the main substances of seed reserves (Tozzi and Takaki 2011) and play an important role in the in vitro morphogenesis (Branca et al 1994;Cangahuala-Inocente et al 2004). As proteins are involved in regulating cell expansion and creation of biophysical characteristics required for seedling morphogenesis (Jiménez 2001), they are commonly consumed during induction of embryogenesis being available for the redifferentiation of somatic cells (Cangahuala-Inocente et al 2009).…”

Contribution of production and seed variables to the genetic divergence in passion fruit under different nutrient availabilities

“…According to Tozzi & Takaki (2011), as germination occurs, the protein bodies identified in the cotyledons are degraded and almost completely consumed up to the moment when radicle protrusion occurs. Therefore, the faster the radicle protrusion process, the more vigorous the seedling is, because it shows greater capacity to transform the reserve supply into meristematic tissues, which may explain the great effect of the variable rootlet size on the coefficient of correlation.…”