Genlisea is a genus of small tropical carnivorous plants distributed throughout Africa and central-south America, growing in wet terrestrial to semi-aquatic environments (1). The main feature of Genlisea is the absence of a true root and a remarkable heterophylly: the plant possesses aerial photosynthetic leaves, or “nomophylls”, and subterranean tubular achlorophyllous leaves called “rhizophylls”, which are and specialized for trapping preys. Genlisea possesses a trapping mechanism comparable to an “eel trap” or a “lobster pot”, that capture a wide range of soil organisms, ranging from unicellular organism as protozoa and algae, to metazoans as crustaceans, mites and nematodes. Preys enters the rhizophylls through openings of the arms and then they can move in a single direction due to the presence of detentive hairs orientated towards the trap vesicle. The vesicle, also called "stomach", is a swelling of the rhizophyll where the digestion and uptake of released nutrients occur. On interior surface of the vesicle there are glands, which are supposed to be responsible for the secretion of digestive enzymes and the absorption nutritional elements. Several species coming from Africa (ie G. hispidula, G. subglabra and G. margaretae) and Central and South America (ie G. pygmaea and G. oxycentron) are currently grown in pots in a climatic chamber. The first objective of this research is the in vitro propagation of Genlisea spp. Preliminary data showed that leaf explants do not survive the sterilization procedure. Consequently, fresh seeds have been harvested from potsgrown plants. The seeds showed resistance to 10% sodium hypochlorite, whereas they have lose germinability after pretreatment whit 70% ethanol. Preliminary results obtained with G. hispidula showed a rate of germination ranging from 8% to 17%, depending on whether the sterilization treatment were done directly on seeds or on the entire capsule. The germination were observed 10 days after the inoculum on hormone-free culture medium. In the early stages of seedling growth it has been observed a peculiar developmental pattern of the shoot apical meristem, which generated alternatively nomophyll and rhizophyll primordia. This pattern is abolished by the presence of cytokinin (BAP) that, even at relatively low concentrations, prevent the development of the rhizophylls and induce the formation of several primordia similar to nomophylls. The next step of this research will consist in the evaluation of the role of auxin in the apical meristem development, and of the combined effect of auxin/cytokinin. Another objective of the research is the study of the different secretory structures present in the rhizophyll, that are currently poorly investigated. Microscopic analysis shown a spherical large body inside the glandular head of digestive glands. The existence of these bodies has been reported only in one paper (2), however no hypothesis has been formulated on its chemical nature and function. In the fresh sections, after 24-48 h, we observed a gradual disappearance of the spherical bodies, that suggests a role in nutrient storage.
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|Titolo:||THE BIZARRE CARNIVOROUS PLANT GENLISEA: IN VITRO PROPAGATION AND MICROSCOPICAL INVESTIGATION OF GLANDULAR STRUCTURES|
|Data di pubblicazione:||2017|
|Appartiene alla tipologia:||04f Poster|