Economic importance of pteridophytes

Thesis Overview

<p> </p><p><b>1.0 &nbsp; &nbsp; Introduction</b></p><p>Man has been using plants as a source<br>of food, medicines and many other necessities of life since ancient times. Even<br>to this day the primitive tribal societies that exist depend on the plant life<br>in their surroundings. Though there were investigations of the edible economic<br>values of the higher plants, especially the pteridophytes and angiosperms have<br>been unfortunately ignored. Pteridophytes existing today represent ancient<br>plant species which appeared about 300 million years ago in the late Devonian<br>period (Fernandez <i>et al</i>.,<br>2011).Pteridophytes including ferns and fern-allies are non-flowering, vascular<br>and sporebearing plants. They form a conspicuous element of the earth’s<br>vegetation and are important from evolutionary point of view as they show the<br>evolution of vascular system and reflect the emergence of seed habit in an the<br>plants. About 250 million years ago, they formed the dominant part of earth’s<br>vegetation. But in present day flora, they have been largely replaced by the<br>seed bearing plants. They grow luxuriantly in moist tropical and temperate<br>forests and their occurrence in different eco-geographically threatened regions<br>from sea level to the highest mountains are of much interest (Dixit, 2000).</p><p>The ferns and fern allies do not form<br>a monophyletic group (Smith, <i>et al</i>.<br>2006) and pteridophyta as a taxonomic group is now regarded as made up of two<br>classes, Lycopodiophyta (fern allies) and Pteridophyta (true ferns) ( Smith<i>&nbsp;et al. </i>2006; WCMC, 1992). The<br>Lycopodiophyta is represented by only five relict genera (Isoetes, Lycopodium,<br>Phylloglossum, Selaginella and Stilites) (WCMC,1992).The Pteridophyta are much<br>more diverse than the Lycopodiophyta, showing great range of form and<br>cosmopolitan in distribution ( WCMC, 1992) Lycopodiophyta and Pteridophyta is a<br>small group of about 12000 species (WCMC, 1992; Chapman, 2009), with some<br>species gathered in the wild for food and medicine, and others cultivated as<br>food and ornamental plants. The ferns are thought by most people to be quite<br>useless members of the plant kingdom. The deleterious effects of rapid fern<br>growth are well publicized, but their useful aspects are largely ignored. Ferns<br>are distributed in all climate zones of the planet, but have a greater<br>diversity in the tropics (Smith <i>et al.,</i><br>2006; Strasburger<i>&nbsp;et al., </i>2003).<br>Ferns show various economic values towards food, fodder indicators,<br>biofertilizers and insect repellents (Ghosh <i>et<br>al.</i>, 2004). Ferns are used as medicines to cure diseases in various<br>countries. In China alone, 401 kinds of pteridophytic medicines have been used<br>for various ailments (Luo 1998).</p><p>Sarker <i>et al</i>. (2011) reported the medicinal uses of 30 pteridophytes of<br>Tamil Nadu. They were used to treat various ailments viz., wound healing, body<br>sickness, diarrhoea, skin problems, body pain, knee problem, cough, cold,<br>fever, asthma, kidney problem, tonic, chronic disorders, several aches, hair<br>growth, stomach problems, ulcer, sore throat, leprosy, ophthalmic, typhoid,<br>urinary bladder and rheumatism. Khare and Kumar (2007) studied ethnobotany of<br>five pteridophytes viz., <i>Adiantum<br>philippense, Diplazium esculentum, Helminthostachys zeylanica, Lygodium<br>flexuosum </i>and<i>&nbsp;Ophiglossum reticulatum</i><br>used by the Tharu tribe of Dudhwa National Park, Lakhimpur-Kheri (U.P). The<br>information collected by Singh <i>et al</i>.<br>(2001) reported that 14 common Pteridophytes were used by the local people of<br>Manipur in various forms. Kirn and Kapathi (2001), observed ethnomedical uses<br>of 19 pteridophytes of Jammu and Kashmir.</p><p>The previous work indicate that the<br>medicinal plants specially the flowering plants are given the more importance<br>in these contents, non-flowering plants particularly fern and fern allies are<br>ignored by scientists. According to Pieroni (2001), evaluation of plant species<br>used in different cultural contexts is necessary in order to infer cultural<br>components related to food acceptance and phytochemical constituents that<br>influence the popularity of edible plants. Plant resources have gained<br>prominence in sub-Saharan Africa as a natural asset through which communities<br>derive food, enabling particularly poor families to achieve self-sufficiency.<br>Documentation of use patterns of pteridophytes across sub-Saharan Africa is of<br>relevance in understanding the importance of this ancient plant group to<br>livelihood strategies of different ethnic groups. This is particularly<br>important for this ancient evolutionary lineage which could potentially become<br>extinct if harvested non-sustainably.</p><br> <br><p></p>