Botanical Research in India in the Domain of Seedling Morphology in Relation to Taxonomy
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ARTICLE BOTANICAL RESEARCH IN INDIA IN THE DOMAIN OF SEEDLING MORPHOLOGY IN RELATION TO TAXONOMY N. D. PARIA* In recent years there has been enormous advancement in different branches of plant science in India since inception of the subject in Vedic period. Various botanical disciplines have reached to the synthesis of diverse new knowledge through the current investigations by the researchers. However, regarding the botanical researches, one very important area of research i.e. study of seedling morphology has not drawn attention of Indian botanists to that extent as in other branches. The present author and his associates have been working in the domain of seedling morphology of Indian flora for more than two decades. In this article, a summarized account of their extensive work has been presented revealing the importance of this unexplored discipline at national level. Introduction marked by the contributions on plant taxonomy, the oldest of botanical disciplines, developed in India during the Vedic ndia has had a long botanical history dating back to period. Later the Portuguese and Dutch, being attracted by ancient times. The first half of the twentieth century the vast potentialities of the country’s flora and vegetation, witnessed considerable botanical activities. There has I initiated the modern study of Indian Plants. Garcia D’Orta’s been a tremendous development in plant science research Coloquios dos simples in 1563 and van Rheede’s Hortus in recent years. Such huge amount of advancement of new Indicus Malabaricus in 1678 were two outstanding knowledge has its genesis since Vedic period. In course of contributions in taxonomic history of India. In 1787, after time, various disciplines of botany, i.e. taxonomy, establishment of the Royal Botanic Garden at Howrah (now morphology, anatomy, cytology, genetics, palaeobotany, known as Acharya Jagadish Chandra Bose Indian Botanic physiology, ecology, economic botany, etc. have emerged Garden) by Col. Robert Kyd there has been a beginning as special fields of researches in India1. In each of these of new era for botanical studies and research in India. Many branches, ongoing progress can be noted till present period eminent botanists from all over the globe came to the including cladistics and molecular approaches. Many of garden and kept their contributions in the floristic study of these areas are being enriched through frontline researches the country. Dr. William Roxburgh, the father of Indian by Indian botanists. These contributions are significant both Botany published the “Flora Indica” in 1832, containing nationally and internationally. The total amount of the beautiful coloured drawings of 2533 species of plants botanical contributions till date reminds us the foundation indigenous to India. His contribution was the basis for of current development of knowledge and achievements in Hooker’s “Flora of British India” (1875 – 1897) published plant science beginning with morphology as well as in seven volumes. The appearance of Hooker’s masterpiece, taxonomy. in the last decade of the nineteenth century gave a great The morphology constituted the first stage of fillip to taxonomic work. Since then numerous books, development in plant science and the earlier years were catalogues, papers, and notes dealing with the flora and vegetation of various provinces and districts have come to * Professor, Taxonomy and Biosystematics Laboratory, Department light and attracted the attention of a large number of of Botany, University of Calcutta, Kolkata-700 019, West botanists2. But none of these taxonomic literature dealt with Bengal, India. E-mail: [email protected] 262 SCIENCE AND CULTURE, SEPTEMBER-OCTOBER, 2014 the study of seedling morphology except the little were examined by Garwood23. Recently Barbosa et al. contribution made by R. S. Troup3. Even though in the studied the seedling morphology of three sympatric savanna twenty-first century taxonomic researches have move species of Byrsonima. This is the first evidence of forwarded to systematic approaches in the field of cryptogeal germination in Malpighiaceae and an overlooked molecular techniques and cladistics but the seedling seedling type in eudicots24. Sokoloff et al. emphasized morphological studies and research still remain unexplored about the embryo and seedling morphology in Trithuria in the context of vast and varied plant biodiversity of India lantern (Hydatellaceae, Nymphaeales). This is a new data which is one of the Megadiversity centers of the world. for infrafamilial systematics and a novel type of syncotyly25. Paria and his associates4 attempted towards extensive Importance of Seedling Morphological Studies: investigations on seedling morphology since 1986, which This is remarkable to state why due attention is to be paid resulted into generation of huge amount of seedling to the study of seedling morphology and its related aspects. morphological data on flowering plants of India till recent Some of the important points are mentioned below. time (2014). These data can be used for taxonomic identification of concerned plants leading to ecological 1. Knowledge of seedlings of plants offers special studies and other purposes of biodiversity research. attention and studies of all their life-cycle stages. 2. Considerable work have been done to describe and Seedling Morphology figure the seedlings of herbs, particularly weeds, Seedling morphology, which is dealt under plant for obvious economic and agricultural reasons. morphology, is a less explored but emerging domain in 3. Knowledge of seedling morphology has emerged plant science. So far the vast botanical Indian literature as a tool for taxonomic studies. are concerned, there is little record of comprehensive studies or research in India in the field of seedling 4. Weed control prefers to focus on the youngest morphology in relation to taxonomy4, until before the huge stages of the weeds. contributions made by the present author and his associates. 5. Regeneration and afforestation programmes largely It is important to mention that an array of workers from depend on seedling growth and recruitment of abroad made significant contributions in this discipline of seedlings particularly in bare areas. seedling morphology with regard to their flora and vegetation, and on the taxonomy of different plant groups. 6. In forestry research the knowledge of seedling stages of wild species is of vital importance, Seedling Studies Abroad: A lot of work on seedling especially in the tropics, because of the highly has been done outside India. The perusal of seedling mixed composition and dynamic structure of the literature reveals that the seedling morphology has been rainforests. investigated for different floras of various countries abroad, some of which include the work from Europe5, South East Constraints Faced by Seedling Plants: Juvenile Asia6, Puerto Rico7, Borneo8, North Western European stages of plants, particularly of trees and shrubs are often Lowland9, Malesia10, etc. From the systematic point of so distinctly different from the adult plant that even with view, an array of workers attempted the seedling expertise and experience of good field knowledge of plants morphological studies on different taxonomic groups, some it appears difficult to recognize the seedlings of adult plants of which are based on Sapotaceae11, Monocotyledons12, of the same species. Due to prevalence of varied abiotic Leguminosae13, Juglandaceae14, Paperomia15, and biotic factors the growth and establishment of seedlings Gymnosperms16, Eucalyptus17, Haplolobus18, etc. are seriously affected and as a matter of fact such bottlenecks render the seedlings highly vulnerable. Their The study of seedlings may clarify the nature of some adversities, although variable in severity depending on morphological characters or document their changes during habitat, soil condition and availability of moisture, non- 19 their development from early stages to adults . Rodrigues availability of sunlight, competition within seedlings and and Tozzi studied systematic relevance of seedling lack of resources during development, the seedlings face morphology in Acosmium, Guianodendron, and considerable constraints to the survival of a plant species. 20 Leptolobium . Sokoloff et al. described seedling diversity In fact, the success in survival of some seedlings of every 21 in Hydatellaceae . Leck et al. published a book on seedling species is critical because ultimately it underlies the 22 ecology and evolution . This book provides a review of development and sustainability of plant communities. Due seedling structure, seedling diversity, morphology, etc. to small size and delicate nature, seedlings are greatly Seedlings of Barro Colorado Island and the Neotropics susceptible to resource limitations and other factors that VOL. 80, NOS. 9–10 263 affect their establishment and subsequent growth. Usually shape and venation pattern of paracotyledons is of a species is characterized to have germinated its seeds, or considerable importance in screening the systematic it may grow in a range of habitats, when it may not find relationships of taxa. Hypocotyl: the hypocotyl is the basal all habitats equally suitable as safe sites for establishment portion of the ascending axis and consists of one ‘internode’ because of varying stress factors. Although germination may only. It is situated between the (para)cotyledonary node occur over a wider range of conditions, establishment and the collet. In species having epigeal