A Historical Perspective of Bladderworts (Utricularia): Traps, Carnivory and Body Architecture

The genus Utricularia includes around 250 species of carnivorous plants, commonly known as bladderworts. The generic name Utricularia was coined by Carolus Linnaeus in reference to the carnivorous organs (Utriculus in Latin) present in all species of the genus. Since the formal proposition by Linnaeus, many species of Utricularia were described, but only scarce information about the biology for most species is known. All Utricularia species are herbs with vegetative organs that do not follow traditional models of morphological classification. Since the formal description of Utricularia in the 18th century, the trap function has intrigued naturalists. Historically, the traps were regarded as floating organs, a common hypothesis that was maintained by different botanists. However, Charles Darwin was most likely the first naturalist to refute this idea, since even with the removal of all traps, the plants continued to float. More recently, due mainly to methodological advances, detailed studies on the trap function and mechanisms could be investigated. This review shows a historical perspective on Utricularia studies which focuses on the traps and body organization.

Charles and Emma Darwin: Under the ‘influence’ of chloroform anaesthesia

A number of Charles Darwin’s biographies record the administration of chloroform by Darwin to his wife Emma, during her labour and delivery of her eighth child, Leonard. This occurred on 15 January 1850, a little over two years after James Young Simpson in Edinburgh described the analgesic action of inhaled chloroform. An online search of more than 9000 items of Darwin’s correspondence at Cambridge University and other sources revealed that he was an active proponent and user of chloroform in midwifery, for euthanising animals he studied, as well as in botanical studies of carnivorous plants. He also discovered that the concurrent inhalation of chloroform, during its administration to his wife, alleviated his distressing anxiety which he suffered when present at her earlier confinements.

Expression and Refolding of the Plant Chitinase From Drosera capensis for Applications as a Sustainable and Integrated Pest Management

Recently, the study of chitinases has become an important target of numerous research projects due to their potential for applications, such as biocontrol pest agents. Plant chitinases from carnivorous plants of the genus Drosera are most aggressive against a wide range of phytopathogens. However, low solubility or insolubility of the target protein hampered application of chitinases as biofungicides. To obtain plant chitinase from carnivorous plants of the genus Drosera in soluble form in E.coli expression strains, three different approaches including dialysis, rapid dilution, and refolding on Ni-NTA agarose to renaturation were tested. The developed « Rapid dilution » protocol with renaturation buffer supplemented by 10% glycerol and 2M arginine in combination with the redox pair of reduced/oxidized glutathione, increased the yield of active soluble protein to 9.5 mg per 1 g of wet biomass. A structure-based removal of free cysteines in the core domain based on homology modeling of the structure was carried out in order to improve the soluble of chitinase. One improved chitinase variant (C191A/C231S/C286T) was identified which shows improved expression and solubility in E. coli expression systems compared to wild type. Computational analyzes of the wild-type and the improved variant revealed overall higher fluctuations of the structure while maintaining a global protein stability. It was shown that free cysteines on the surface of the protein globule which are not involved in the formation of inner disulfide bonds contribute to the insolubility of chitinase from Drosera capensis. The functional characteristics showed that chitinase exhibits high activity against colloidal chitin (360 units/g) and high fungicidal properties of recombinant chitinases against Parastagonospora nodorum. Latter highlights the application of chitinase from D. capensis as a promising enzyme for the control of fungal pathogens in agriculture.

A new carnivorous plant lineage (Triantha) with a unique sticky-inflorescence trap

Carnivorous plants consume animals for mineral nutrients that enhance growth and reproduction in nutrient-poor environments. Here, we report that Triantha occidentalis (Tofieldiaceae) represents a previously overlooked carnivorous lineage that captures insects on sticky inflorescences. Field experiments, isotopic data, and mixing models demonstrate significant N transfer from prey to Triantha, with an estimated 64% of leaf N obtained from prey capture in previous years, comparable to levels inferred for the cooccurring round-leaved sundew, a recognized carnivore. N obtained via carnivory is exported from the inflorescence and developing fruits and may ultimately be transferred to next year’s leaves. Glandular hairs on flowering stems secrete phosphatase, as seen in all carnivorous plants that directly digest prey. Triantha is unique among carnivorous plants in capturing prey solely with sticky traps adjacent to its flowers, contrary to theory. However, its glandular hairs capture only small insects, unlike the large bees and butterflies that act as pollinators, which may minimize the conflict between carnivory and pollination.

Non-Nepenthes Carnivorous Plants in Indonesia: Current Knowledge on Diversity, Ethnobotany, and Phytochemistry

One of the most unique plant groups in the world is carnivorous plants. Indonesia is home to many species of this plant group. Nepenthaceae, represented by single genus Nepenthes, is relatively well known, but the others are not. A literature study and several field trips were conducted to give a summary of the diversity and the potential uses of the non-Nepenthes carnivorous plants in Indonesia. Three families with a total number of 29 species have been reported for Indonesia, namely Lentibulariaceae (20 species), Droseraceae (8 species), and Byblidaceae (1 species). One species, Aldrovanda vesiculosa is listed as Endangered based on IUCN Red List. The results reveal that several species possess ethnobotanical and medicinal uses as well as other potential such as in phytoremediation and nanoparticle biosynthesis. Several bioactivities have been reported such as anticancer, antihypertensive, antitumor, antioxidant, antibacterial, or even hepatoprotective. Among the most important bioactivity is anticancer which is supported by the presence of secondary metabolites named plumbagin, which so far has been found in three species. Our result indicates that this plant group is highly potential and warrants further studies and or development.

Nutrient and metal concentrations in Nepenthes macfarlanei Hemsl. (Nepenthaceae) from a Malaysian montane forest

Palaeotropical pitcher plants (Nepenthes) are a fascinating evolutionary case but their nutrient relationships are poorly known. To determine nutrient and metal concentrations in Nepenthes macfarlanei from Peninsular Malaysia, and contribute to our understanding of nutrient relationships in this genus, plants were sampled from the Genting Highlands – a disturbed montane forest location. Whilst many foliar nutrients showed typical concentrations, the foliar N concentration was, surprisingly, greater than most lowland species although the N:P ratio (c. 24) indicated nitrogen limitation in line with other studies on Nepenthes. Of particular note was the variable but high (< 240 µg g-1) lead concentrations that have not been reported in carnivorous plants before. This data adds to our understanding of the nutrient relationships of carnivorous plants and shows that they may accumulate high concentrations of certain metals.

Leaf Shape Diversity: From Genetic Modules to Computational Models

Plant leaves display considerable variation in shape. Here, we introduce key aspects of leaf development, focusing on the morphogenetic basis of leaf shape diversity. We discuss the importance of the genetic control of the amount, duration, and direction of cellular growth for the emergence of leaf form. We highlight how the combined use of live imaging and computational frameworks can help conceptualize how regulated cellular growth is translated into different leaf shapes. In particular, we focus on the morphogenetic differences between simple and complex leaves and how carnivorous plants form three-dimensional insect traps. We discuss how evolution has shaped leaf diversity in the case of complex leaves, by tinkering with organ-wide growth and local growth repression, and in carnivorous plants, by modifying the relative growth of the lower and upper sides of the leaf primordium to create insect-digesting traps.

Sarracenia alata (Alph.Wood) Alph.Wood Microcuttings as a Source of Volatiles Potentially Responsible for Insects’ Respond

Rare carnivorous plants representing the genus Sarracenia are perceived as very interesting to scientists involved in various fields of botany, ethnobotany, entomology, phytochemistry and others. Such high interest is caused mainly by the unique capacity of Sarracenia spp. to attract insects. Therefore, an attempt to develop a protocol for micropropagation of the Sarracenia alata (Alph.Wood) Alph.Wood, commonly named yellow trumpets, and to identify the specific chemical composition of volatile compounds of this plant in vitro and ex vivo was undertaken. Thus, the chemical volatile compounds excreted by the studied plant to attract insects were recognized with the application of the headspace solid-phase microextraction (HS-SPME) coupled with the GC-MS technique. As the major volatile compounds (Z)-3-hexen-1-ol (16.48% ± 0.31), (E)-3-hexen-1-ol acetate (19.99% ± 0.01) and β-caryophyllene (11.30% ± 0.27) were identified. Further, both the chemical assumed to be responsible for attracting insects, i.e., pyridine (3.10% ± 0.07), and whole plants were used in in vivo bioassays with two insect species, namely Drosophila hydei and Acyrthosiphon pisum. The obtained results bring a new perspective on the possibilities of cultivating rare carnivorous plants in vitro since they are regarded as a valuable source of bioactive volatile compounds, as including ones with repellent or attractant activity.