Anti-predation strategies in pteridophytes—a biochemical approach

Abstract

SynopsisSince they first evolved, pteridophytes have been subjected to attack by micro-organisms and arthropods. Present-day ferns are associated with a complex array of, not only phytophagous, scavenging, predatory and parasitic arthropod species but also fungi, bacteria, viruses and herbivorous mammals.Recent research has tended to stress the importance of secondary plant chemistry in deterring feeding by herbivores and attack by pathogens. Although ferns have a more limited chemical repertoire than the angiosperms, many of the classes of secondary compounds isolated from ferns have been shown to have anti-microbial and anti-herbivore activity under both laboratory and field conditions. Quantitative and qualitative levels are not constant and show great seasonal variation. This chemical variation is important in determining the seasonal patterning of insects and fungi on ferns. New chemical techniques are increasing our knowledge of the biosynthesis and chemical structures of these ecologically important compounds.Flowering plants show both constitutive and induced resistance as a consequence of herbivore attack. A search for short-term induced chemical responses in ferns have so far yielded negative results in terms of phytoalexin synthesis or direct chemical response to herbivory.