The Secretory Apparatus of Tabernaemontana ventricosa Hochst. ex A.DC. (Apocynaceae): Laticifer Identification, Characterization and Distribution

Abstract

Due to the inconsistencies in the interpretation of laticifers within the Apocynaceae, the current study aimed to distinguish, for the first time, the type and distribution of the laticifers in the embryos, seedlings and adult plants of Tabernaemontana ventricosa (Forest Toad tree). The characterization and distribution of laticifers were determined using light and electron microscopy. The findings revealed the presence of articulated anastomosing laticifers. The laticifers were found to have originated from ground meristematic and procambium cells and were randomly distributed in all ground and vascular tissue, displaying complex branching conformations. The presence of chemical constituents within the laticifers and latex determined by histochemical analysis revealed the presence of alkaloids, phenolics, neutral lipids, terpenoids, mucilage, pectin, resin acids, carboxylated polysaccharides, lipophilic, and hydrophilic substances and proteins. These secondary metabolites perform an indispensable role in preventing herbivory, hindering and deterring micro-organisms and may possibly have medicinal importance. The outcomes of the present study outlined the first micromorphology, anatomy, ultrastructural and chemical analysis of the laticifers of T. ventricosa. In addition, this investigation similarly established the probable functions of latex and laticifers.

Laticifer Identification, Rubber Characterization, Phenolic Content, and Antioxidant Activity of Pergularia tomentosa Latex Extract

“…Obtained results were in accordance to those found previously for other Asclepiadaceae [ 12 , 27 , 36 , 38 ]. While in other study, secretory cells were found towards leaf extremities [ 26 ].…”

“…[ 37 ]. However, they can occur in the vascular tissue and cortical parenchyma in other species sections [ 26 ].…”

“…Latex production was combined to a distortion of cell contents leading, thus, a supply of required energy and an abundance of mitochondria, lipid bodies, starch grains, and osmiophilic structure transferred to the central vacuole [ 25 ]. The discontinuity of transverse cell walls associated to cell accumulation in protoplast is responsible of laticiferous cell creation [ 24 , 26 ]. Latex secretion implies protoplasm degeneration, restriction of the cytoplasm, and fusion of small vacuoles with some vesicles into the central vacuole [ 27 ].…”

Leaf anatomy of two medicinal Croton species: Contribution to plant recognition

“…Laticifers contain a complex solution including neutral lipids, acidic lipids, and phenolic compounds essential for the defense of plants against biotic and abiotic stresses (Naidoo, Naidoo, & Dewir, 2020; Pott, Osorio, & Vallarino, 2019). According to Vitarelli et al (2015), laticifers in the Crotoneae subtribe are the articulated type; they can be present in the subfamily Crotonoideae and constitute a plesiomorphic character for Euphorbiaceae.…”

The Micromorphology and Histochemistry of Foliar Mixed Indumentum of Leucas lavandulaefolia (Lamiaceae)

“…The leaf segments were secured onto brass stubs with double-sided carbon conductive tape, and sputter-coated with gold for 3 min, using a Polaron SC500 Sputter Coater (Hemel Hempstead, London). A LEO 1450 scanning electron microscope at 5 kV was used to observe the leaf samples [ 19 ]…”