Structural Features of Carnivorous Plant (Genlisea, Utricularia) Tubers as Abiotic Stress Resistance Organs

Abstract

Carnivorous plants from the Lentibulariaceae form a variety of standard and novel vegetative organs and survive unfavorable environmental conditions. Within Genlisea, only G. tuberosa, from the Brazilian Cerrado, formed tubers, while Utricularia menziesii is the only member of the genus to form seasonally dormant tubers. We aimed to examine and compare the tuber structure of two taxonomically and phylogenetically divergent terrestrial carnivorous plants: Genlisea tuberosa and Utricularia menziesii. Additionally, we analyzed tubers of U. mannii. We constructed phylogenetic trees using chloroplast genes matK/trnK and rbcL and used studied characters for ancestral state reconstruction. All examined species contained mainly starch as histologically observable reserves. The ancestral state reconstruction showed that specialized organs such as turions evolved once and tubers at least 12 times from stolons in Lentibulariaceae. Different from other clades, tubers probably evolved from thick stolons for sect. Orchidioides and both structures are primarily water storage structures. In contrast to species from section Orchidioides, G. tuberosa, U. menziesii and U. mannii form starchy tubers. In G. tuberosa and U. menziesii, underground tubers provide a perennating bud bank that protects the species in their fire-prone and seasonally desiccating environments.

Living between land and water – structural and functional adaptations in vegetative organs of bladderworts

“…The corkscrew plants (Genlisea) comprise 31 species of amphiphytes and few emergent hydrophytes (Fleischmann 2012(Fleischmann , 2018Silva et al 2020b). Genlisea is considered being heterophyllous, having non-carnivorous rosettes of green leaves above ground and subterranean "rhizophylls" that function like an eel-trap (Reut 1993;Fleischmann 2018;Płachno and Muravnik 2018).…”

“…Płachno and Jankun 2004;Płachno et al 2019a). Most recently, Płachno et al (2020b) described structures of tubers in one Genlisea and two Utricularia species showing adaptation to abiotic stress (e.g. seasonal drought or fire).…”

Response of a carnivorous plant to simulated herbivory

“…4). Starch storage in stressresistant organs has been documented in other Pinguicula species (Heslop-Harrison 2004) and in other members of the Lentibulariaceae (Płachno et al 2014(Płachno et al , 2020. Thus, it is possible that P. moranenis could reallocate resources between growth and resistant organs.…”

“…Further experiments are needed to specifically demonstrate that tolerance to loss of leaf tissue in this species depends, at least partially, on the ability to reallocate stored resources. Such studies could, in fact, consider the possibility that winter(resistant) rosettes store substances other than starch, for example, protein bodies have been observed in other carnivorous plants (Płachno et al 2014(Płachno et al , 2020 or lipids (Płachno et al 2014). In Pinguicula, resources could also be stored in roots (Heslop-Harrison 2004).…”

Plant diversity on the edge: floristics, phytogeography, fire responses, and plant conservation of Two Peoples Bay Nature Reserve in the context of OCBIL theory

“…Some of these taxa have evolved resilience to drought through extraordinary abilities to recover from dehydration, specifically species of Borya (Porembski and Barthlott 2000), or through the development of microgeophytic seed-like corms or tubers. These structures are able to tolerate high temperatures, and are observed in Philydrella, Phylloglossum, and Utricularia, for example (Dixon et al 1983;Płachno et al 2020). One drought-resilient species, T. isantherus, is on the list of species of special conservation concern for the Reserve (Table 2).…”