Gland cell responses to feeding in Drosera capensis, a carnivorous plant

Abstract

Glands of Drosera absorb and transport nutrients from captured prey, but the mechanism and dynamics remain unclear. In this study, we offered animal proteins in the form of fluorescent albumin (FITC-BSA) and observed the reactions of the glands by live cell imaging and fluorescence microscopy. The ultrastructure of these highly dynamic processes was also assessed in high-pressure frozen and freeze substituted (HPF-FS) cells. HPF-FS yielded excellent preservation of the cytoplasm of all cell types, although the cytosol looked different in gland cells as compared to endodermoid and stalk cells. Especially prominent were the ER and its contacts with the plasma membrane, plasmodesmata, and other organelles as well as continuities between organelles. Also distinct were actin microfilaments in association with ER and organelles. Application of FITC-BSA to glands caused the formation of fluorescent endosomes that pinched off the plasma membrane. Endosomes fused to larger aggregates, and accumulated in the bulk cytoplasm around the nucleus. They did not fuse with the cell sap vacuole but remained for at least three days; in addition, fluorescent vesicles also proceeded through endodermoid and transfer cells to the epidermal and parenchymal cells of the tentacle stalk.

Immunocytochemical Analysis of the Wall Ingrowths in the Digestive Gland Transfer Cells in Aldrovanda vesiculosa L. (Droseraceae)

“…[ 69 ]. As reported by Lichtscheidl et al [ 9 ], in these cells, membrane recycling to prevacuolar compartments and vacuoles occurs for arabinogalactan proteins. This may be connected with prey digestion and subsequent endocytosis of nutrients.…”

“…External glandular cells are exposed to stress associated with contact with bacteria or fungal pathogens and to mechanical damage caused by captured animals. Thus, they are an ideal model for studying plant cyto-architecture, membrane organization, and dynamics of organelle interactions [ 4 , 5 , 6 , 7 , 8 , 9 ]. In glandular cells, transport of materials into or out of the gland occurs through the symplast and apoplast.…”

The digestive systems of carnivorous plants

“…The mucilage of Drosera binata contains an acidic polysaccharide comprising arabinose, galactose, glucuronic acid, mannose, and xylose ( Gowda et al, 1982 ; Erni et al, 2008 ), while the acidic polysaccharide of D. capensis is slightly modified and is composed of ester sulfate, galactose, glucuronic acid, mannose, and xylose ( Rost and Schauer, 1977 ). Across Drosera , however, the Golgi apparatus appears to be responsible for both mucilage production and secretion ( Schnepf, 1961a ; Dexheimer, 1978 ; Outenreath and Dauwalder, 1986 ; Lichtscheidl et al, 2021 ). The glands of the Caryophyllales carnivores Triphyophyllum and Drosophyllum also produce acidic secretions.…”

“…The plant epidermis is usually protected by a continuous cuticle, but gland cells of carnivorous plants often show cuticular pores or gaps that allow the passage of small molecules. The presence of such cuticular discontinuities has been revealed in many carnivorous plants using electron microscopy and staining with dyes such as methylene blue, which cannot penetrate intact cuticles ( Juniper et al, 1989 ; Płachno et al, 2007 ; Adlassnig et al, 2012 ; Koller-Peroutka et al, 2019 ; Lichtscheidl et al, 2021 ). While the glands of many species exhibit cuticular permeability, there are some inter-species differences ( Adlassnig et al, 2012 ).…”

Ultrastructure of plant cells

“…Several ultrastructural changes, such as fine wall ingrowths, higher contents of Zn and Cu in epidermal and glandular cells were detected suggesting structural properties of glandular heads involved in the secretion of toxic metal ions. Lichtscheidl et al (2021) contributed another interesting study on Drosera capensis a carnivorous plant and a less studied object in cell biology. Gland cells absorb and transport nutrients, a system that was experimentally targeted by offering fluorescent albumin and following its uptake.…”