The Roots of Carnivorous Plants

Abstract

Carnivorous plants may benefit from animal-derived nutrients to supplement minerals from the soil. Therefore, the role and importance of their roots is a matter of debate. Aquatic carnivorous species lack roots completely, and many hygrophytic and epiphytic carnivorous species only have a weakly developed root system. In xerophytes, however, large, extended and/or deep-reaching roots and sub-soil shoots develop. Roots develop also in carnivorous plants in other habitats that are hostile, due to flooding, salinity or heavy metal occurance. Information about the structure and functioning of roots of carnivorous plants is limited, but this knowledge is essential for a sound understanding of the plants' physiology and ecology. Here we compile and summarise available information on:(1) The morphology of the roots.(2) The root functions that are taken over by stems and leaves in species without roots or with poorly developed root systems; anchoring and storage occur by specialized chlorophyll-less stems; water and nutrients are taken up by the trap leaves. (3) The contribution of the roots to the nutrient supply of the plants; this varies considerably amongst the few investigated species. We compare nutrient uptake by the roots with the acquisition of nutrients via the traps. (4) The ability of the roots of some carnivorous species to tolerate stressful conditions in their habitats; e.g., lack of oxygen, saline conditions, heavy metals in the soil, heat during bushfires, drought, and flooding.

Integration of trap‐ and root‐derived nitrogen nutrition of carnivorous Dionaea muscipula

“…However, inorganic N will become available in the soil of these environments upon sporadic fire events (Roberts & Oosting, 1958). Adapted to low nutrient availability in the soil, D. muscipula develops only four to eight unbranched roots (Smith, 1931) and does not seem to form symbiotic partnerships with mycorrhizal fungi (Adlassnig et al, 2005). Compared with noncarnivorous plants, D. muscipula is therefore thought to be a poor competitor for soil nutrients (Adlassnig et al, 2005).…”

“…Adapted to low nutrient availability in the soil, D. muscipula develops only four to eight unbranched roots (Smith, 1931) and does not seem to form symbiotic partnerships with mycorrhizal fungi (Adlassnig et al, 2005). Compared with noncarnivorous plants, D. muscipula is therefore thought to be a poor competitor for soil nutrients (Adlassnig et al, 2005). However, Adamec (2005) found D. muscipula roots to be very active, exhibiting large rates of (cyanide-resistant) respiration, which was interpreted as an adaptive trait to endure permanent soil anoxia (Adamec, 2005).…”

Lentibulariaceae no Parque Estadual do Ibitipoca, Minas Gerais, Brasi

“…são as únicas dentro do gênero que podem ocorrer em tanques de bromélias, especificamente Vriesea e Alcantarea. Apresentam estolão robusto que permite o armazenamento de nutrientes garantindo a resistência da planta em épocas de enchentes/cheia (Adlassnig et al 2005).…”

Insecticides reduce survival and the expression of traits associated with carnivory of carnivorous plants

“…Along with most carnivorous plant species, pink sundews and Venus flytraps have small, fragile roots (Adlassnig et al 2005) and their leaf surfaces are covered in digestive glands (Juniper et al 1989), both of which could increase their susceptibility to insecticides in comparison to many other plants. Consequently, our hypotheses were as follows: 1) insecticides will directly reduce the survival of carnivorous plants, and 2) given that carnivorous plants under stress often reduce their expression of traits associated with carnivory (i.e.…”