Studies in the seedling phenology and role of seedling in clonally propagated species Hellenia speciosa (J.Koenig) S.D.Dutta

Abstract

Hellenia speciosa (J. Koenig) S.D.Dutta, a clonally propagated plant, widely known as crepe ginger, is an important medicinal plant of tropical Asia. It is a rich source of diosgenin- a phytosteroid sapogenin used in the commercial synthesis of progesterone. Despite clonal propagation, the plant produces a substantial number of viable seeds, which later become short-lived seedlings. Therefore, this research aims to comprehend the phenological behaviour of the seedling and its significance in clonal development. The study will also help understand the role of ramets in establishment vis-à-vis rapid colonization of the plant. Studies on seed germination and phenology of seedling genet have revealed significant phenological and morphological features. Seed germination is of epigeal and phanerocotylar type producing seedling genet with orbicular obovate cotyledon, glabrous hypocotyl and spiromonostichous phyllotaxy. Leaf shape varies from narrowly ovate to lanceolate. Horizontal rhizome develops from the base of the seedling epicotyl and produces 4-5 ramets in the same growing season. Morphometry of leaf length and breadth of seedling is positively correlated with that of reproductive ramet of the previous growing season (leaf length: r=0.99, p<0.001; leaf breadth: r= 0.79, p<0.05). The plant shows rhizomatous dependency for maturity as seedling genets are short-lived. So it could be concluded that the primary role of the short-lived seedling genet is to provide a foundation for rhizome development. Additionally, the seedling appears as a miniature of the adult reproductive ramet. Here, during the first growing season, the species allocate more resources for the vegetative growth of its ramet rather than reproductive development. The reproductive development starts from the next growing season.