Pericarp Peltate Trichomes in Pterocarya rhoifolia: Histochemistry, Ultrastructure, and Chemical Composition
2011
Muravnik, Lyudmila E. | Shavarda, Alexey L.
Morphology, ultrastructure, and histochemistry of the peltate trichomes on the pericarp surface in Pterocarya rhoifolia were studied, and metabolites that they contain were identified. Samples of the pericarp were fixed and processed for light and electron microscopy. Peltate trichomes are situated on the whole surface of the young fruit including its wings. They have a large disk-shaped head and a short stalk. Typically, the secretory cells have a continuous cuticle and loose cell wall structure in which the secretion accumulates. During the secretory stage, these cells contain rough and smooth endoplasmic reticulum, Golgi stacks with large and coated vesicles, diversiform leucoplasts in contact with a reticular sheath, and opaque deposits in the vacuoles. Histochemical tests and fluorescence microscopy demonstrate the presence of pectins, lipids, tannins, and phenylpropanoids in the secretory cells. Gas chromatography-mass spectrometry was used to determine the content of metabolites in methanol extracts from the pericarp with trichomes and from isolated trichomes. Several phenolic substances (catechin, quercetin) as well as sugar alcohols were found only in the trichomes. On the basis of the histochemistry, fluorescent microscopy, and ultrastructure as well as the chemical analysis of the methanol extracts, it may be concluded that synthesis and accumulation of phenolic substances takes place in the peltate trichomes.
显示更多 [+] 显示较少 [-]