The roots of carnivorous plants Wolfram Adlassnig 1 , Marianne Peroutka 1 , Hans Lambers 2 & Irene K. Lichtscheidl 1,3 1 Institute of Ecology and Conservation Biology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria. 2 School of Plant Biology, Faculty of Natural and Agricultural Sciences, The University of Western Australia, Crawley WA 6009, Australia. 3 Corresponding author* Received 30 April 2004. Accepted in revised form 31 August 2004 Key words: carnivorous plants, insectivorous plants, morphology, nutrition, root 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 devel- oped 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 flood- ing, salinity or heavy metal occurance. Information about the structure and functioning of roots of car- nivorous 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 nutri- ents 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. Introduction to carnivorous plants Plants benefit in many ways from animals; e.g., animals play a role as pollinators and as dispers- ers of fruits. However, animals may also contrib- ute to a plant’s nutrition by being caught and digested. This phenomenon of carnivory has fascinated the scientific community ever since Darwin drew attention to it (Darwin, 1875). Although carnivorous plants can obtain water and at least some minerals from the soil, they also extract nutrients from captured animals. Carnivorous plants attract their victims by means of scent, colouration and nectar (Lloyd, 1942). They are able to trap and retain their victims, kill them, and digest their soft tissues, and take up at least part of their contents (Juniper et al., 1989; Lloyd, 1942). This whole process is achieved by highly specialized leaves, which have been transformed into various types of traps. Therefore, the leaves may take over functions that are usually restricted to the roots of non- carnivorous plants. The general features of car- nivorous plants have been reviewed in detail by Juniper et al. (1989). Five types of traps can be distinguished: * E-mail: irene@pflaphy.pph.univie.ac.at Plant and Soil (2005) 274:127–140 Ó Springer 2005 DOI 10.007/s11104-004-2754-2