The abiotic environment of Heliamphora nutans (Sarraceniaceae): pedological and microclimatic observations on Roraima Tepui

Abstract

The aim of this study was the study of the abiotic environment of the carnivorous pitcher plant

Plant behaviour: an evolutionary response to the environment?

“…In particular, Heliamphora nutans (Fig. 3), a plant endemic to South America, secretes nectar to attract insects into the ascidium (flask-shaped organ), where liquids rich in digestive enzymes accumulate (Adlassnig et al, 2010). Furthermore, Heliamphora produces components that reduce surface tension of the flask lip to facilitate the fall of many insects into the ascidium (Bauer et al, 2013).…”

Replicated radiations in the South American marsh pitcher plants (Heliamphora) lead to convergent carnivorous trap morphologies

“…Such widespread convergence is often associated with adaptation to a common ecological niche (Donoghue et al, 2022), and previous authors suggest that small pitchers may be favored in habitats with suboptimal growth conditions, e.g., shallow or infertile substrates, heavy shade, and periodic drought or heat stress (Wistuba et al, 2002; Givnish et al, 2018). Small pitchers impose lower construction costs (Karagatzides and Ellison, 2009; McPherson et al, 2011) and are more drought and heat tolerant due to the reduced transpiration from the pitcher and evaporation from the pitcher fluid (Adlassnig et al, 2010).…”

“…At a high level, the pitcher fluid can effectively rise along the pubescent inner pitcher wall up to the rim by capillary action, forming superhydrophilic (slippery) trapping surface that facilitates prey capture (Jaffe et al, 1992; Bauer et al, 2013). The regulation and maintenance of the pitcher fluid level might be important in other ecological functions, such as thermal regulation, water reservoir during hot and dry periods, and microhabitat for commensal microbiomes to facilitate digestion (Jaffe et al, 1992; Nerz, 2004; Adlassnig et al, 2010). We expect that there are also lower limits on pitcher fluid level, bounded by the minimum volume needed to allow for carnivorous functions.…”

“…We sampled 23 described and 2 additional yet‐to‐be described taxa of Heliamphora for this study (Appendix S1, Table S1). All specimens were grown under controlled environmental conditions [photoperiod 15 hr per day (full sun); temperature range 12–25°C; relative humidity >80%], resembling the climates of their native habitats (Jaffe et al, 1992; Adlassnig et al, 2010). Species determinations of the living collections were confirmed by comparing their morphological traits to the original descriptions (Bentham, 1840; Nerz and Wistuba, 2000; Carow et al, 2005; Fleischmann et al, 2009; McPherson et al, 2011).…”

Replicated radiations in the South American Marsh Pitcher genus Heliamphora (Sarraceniaceae) lead to convergent carnivorous trap morphologies

“…Donoghue et al 2022), and previous authors suggest that small pitchers may be favored in habitats with suboptimal growth conditions, e.g., shallow or infertile substrates, heavy shade, and periodic drought or heat stress (Wistuba, Carow, and Harbarth 2002;Givnish et al 2018). Small pitchers impose lower construction costs (Karagatzides and Ellison 2009; and are more drought and heat tolerant due to the reduced transpiration from the pitcher and evaporation from the pitcher fluid (Adlassnig, Pranjic, et al 2010). Overall, the diversity of habitats provided by the topologically complex Pantepui region combined with the geological isolation between tepuis may account for the repeated diversification of pitcher size in each clade and the resulting convergence across the genus.…”