Ultrastructural Analysis of the Digestive Gland Secretory and Absorptive Processes in Nepenthes glandulifera

Nepenthes glandulifera is a carnivorous pitcher plant native to tropical environments, of which the majority live on the islands in the Malay Archipelago where sunlight and water are abundant. The pitcher trap style contains a modified pitfall trap that attracts insects and other small invertebrates through various attractive mechanisms. These plants also contain digestive glands that secrete digestive fluid to break down prey into nutrients for the plant. The digestive fluid, with remarkably unique properties, has been analyzed in relation to multiple areas of study including the development of an enzyme-supplementation strategy for the treatment of celiac disease and the synthesis of gold nanoparticles for tumor imaging and targeting. Although the composition of the digestive fluid has been studied, there is limited data on the ultrastructural components of the digestive glands. In this study, electron and light microscopy were used to analyze the digestive glands in relation to the secretory and absorptive processes in Nepenthes glandulifera. Electron and light microscopy data suggest that Nepenthes use limited symplastic and apoplastic transport, requiring transmembrane transporters for nutrient uptake. A novel structure in the nucleus of multiple cells suggests an evolved mechanism for the continuous acidification of pitcher fluid and intracellular communication for rapid and efficient nutrient uptake