Secretory cells in Piper umbellatum (Piperaceae) leaves: A new example for the development of idioblasts

Abstract

a b s t r a c tThis work aims to investigate the origins and development of secretory cells in Piper umbellatum (L.) Miq. (Piperaceae) leaves as well as the course and the nature of their secretion. The results were compared with studies in oil-secreting cells of several species. Fully expanded fresh leaves were sectioned and subjected to different histochemical tests. Leaves in different developmental stages were fixed and processed for study under light and scanning and transmission electron microscopy techniques. The secretory cells show mixed secretion made up of hydrophobic (oleoresin) and hydrophilic (phenolic compounds and alkaloids) compounds. Secretory cells originate either from the protodermis or the ground meristem. The growth of these cells occurs primarily by increasing the volume of the central vacuole, which corresponds to an extraplasmatic space connected to a protuberance of the wall. Electron-opaque compounds are observed initially in leucoplasts, while electron-dense compounds occur in small vesicles in the cytoplasm. Both are accumulated in the central vacuole which is already developed. Besides the mixed chemical nature of the secretion identified in secretory cells of P. umbellatum leaves, these secretory cells differ from those that have already been described mainly because of the development of the central vacuole prior to the accumulation of the secretion.

Efficiency of the Polyethylene-Glycol (PEG) Embedding Medium for Plant Histochemistry

“…The results of the current study reinforce the applicability of Karnovsky's solution for histochemical analyses, and its usefulness when fresh material is not available. Fresh samples (T1) are commonly used in basic histochemical analyses (Johansen 1940;Jensen 1962;Kraus and Arduin 1997;Santos et al 2008;Lopes et al 2009;Coutinho et al 2010;Marinho et al 2011;Ventrella et al 2013) and are therefore herein considered as controls for the purpose of comparison. Neither fixation nor embedding in PEG alters the histochemical results, with the exception of the false-negative results obtained when using T3 for the detection of polyphenols, lignins and flavonoidic derivatives.…”

Organ-Level Analysis of Idioblast Patterning in Egeria densa Planch. Leaves

“…A final example of autofluorescence comes from secretory idioblasts in Piper umbellatum leaves. These idioblasts accumulate phenolic compounds, alkaloids, and lipids in their vacuoles [ 32 ].…”

Idioblasts formation and essential oil production in irrigated Piper aduncum

“…The essential oil production is related to the presence of secretory structures, such as idioblasts and secretory trichomes (Silva & Machado 1999, Marinho et al 2011, Tozin et al 2015. Idioblasts are present in all parts of P. aduncum plants, mostly in the leaves (Lakshmia & Naidu 2010, Marinho et al 2011, Gogosz et al 2012, Nakamura et al 2015, Santos et al 2018, which are the source for the highest amounts of essential oil.…”

“…The essential oil production is related to the presence of secretory structures, such as idioblasts and secretory trichomes (Silva & Machado 1999, Marinho et al 2011, Tozin et al 2015. Idioblasts are present in all parts of P. aduncum plants, mostly in the leaves (Lakshmia & Naidu 2010, Marinho et al 2011, Gogosz et al 2012, Nakamura et al 2015, Santos et al 2018, which are the source for the highest amounts of essential oil. These secondary metabolism compounds are targeted by the chemical industry and present multiple biological effects exploited as insecticides, fungicides, molluscicides, acaricides, bactericides and larvicides, with the advantage of being biodegradable products (Zacaroni et al 2009, Costa et al 2010, Pino et al 2011, Piton et al 2014, Rapado et al 2014, Santos & Siviero 2015, Pinto et al 2016.…”