Germination-Associated Morphological and Anatomical Changesin Corypha umbraculifera L. Seeds

摘要

Corypha umbraculifera L. commonly known as 'Talipot palm' is a highly endangered species belonging to the family Arecaceae. C. umbraculifera is monocarpic and usually flowers after 30-60 years of growth. Seeds of C. umbraculifera are recalcitrant andgermination rate is very low. The objective of this study was to investigate the seed germination behaviour and germination associated morphological and anatomical changes in C. umbraculifera. Seeds are of albuminous type and the endosperm is very hard due to thick polysaccharide deposits on the cell wall and the embryo occupies the peripheral position. A range of 64 to 77 days are required for germination of all seeds in a given lot, whereas 64 to 128 days are required for the completion of germinationand establishment of the seedling. Germination begins with the opening of an operculum, through which the cotyledonary sheath emerges out carrying the embryonic atfis at the tip and it is highly gravitropic. The portion of the cotyledon that remains inside the seed develops into a haustorium. The plumule is differentiated inside the thick, fleshy, plumular sheath which develops inside the cotyledonary sheath and emerges through the cleft formed on the plumular sheath and hence the type of germination is remotive. As germination starts, the tip of the cotyledonary sheath becomes meristematic and provascular strands are developed between cotyledonary sheath and the haustorium. Anatomical features of the growing tip of the cotyledonary sheath resemble the structure of a typical root apex consisting of a 'root cap' and elongating region.