A ocorrência de plasmodesmas no endosperma de Coffea arabica L. var. typica Cramer

Abstract

O endosperma de café, tratado segundo a técnica utilizada por Crafts nos seus estudos com Solanum tuberosum L., evidenciou a ocorrência de plasmodesmas nas paredes de suas células. Êstes plasmodesmas apresentam-se como filamentos tênues, na maioria dos casos geniculados e agregados em grupos, localizados nos "campos de pontuações primárias". O aspecto, a morfologia, a freqüência e a distribuição dos plasmodesmas, no endosperma de café, são sensivelmente semelhantes às estruturas vistas e descritas por Quisumbing, em Diospyros kaki L.

Cytology, biochemistry and molecular changes during coffee fruit development

“…The existence of intense transfer between the perisperm and endosperm should also explain why starch was strongly detected in the outer perisperm but undetectable in inner perisperm cells localized close to the endosperm (Geromel et al, submitted). Large exchanges and diffusion of metabolites are also supposed to occur in the parenchymatous cells of the endosperm and could be facilitated by the presence of plasmodesmata (De Melo Ayres, 1954;Dentan, 1985a). This should help the migration of diterpenes, phenolic compounds and serotonine (5-hydroxytryptamine) from the internal endosperm to its epiderm, as has been reported for the last stages of bean maturation (Dentan, 1985b).…”

“…Walls of both cell types are crossed by plasmodesmata that should permit exchange of solute compounds between cells (De Melo Ayres, 1954;Dentan, 1985aDentan, , 1985b. It is also a hard tissue, due to the high polysaccharide deposition in the cell walls (Wolfrom et al, 1961;Wolfrom and Patin, 1964).…”