Somaclonal Variation in Regenerants from Long-Term Embryonic Cultures of Chlforophytum borivilianum Obtained from Agamospermic Seeds of a Triploid Plant

摘要

Chlorophytum borivilianum is an endangered aphrodisiac plant and most of the plants in nature are triploid. Agamospermic seeds of a triploid plant were used to initiate somatic embryogenesis. Plantlets obtained through seedling-derived embryonic callus showed high level of morphological and cytological variation, which increased with the increase in age of cultures. Variegated leaves were also observed occasionally. High level of variation in the leaf size, stomata number and epidermal cell size wasobserved. Increase in the variation in chromosome number was observed with the increase in age of cultures. Chromosomal variation was least 2n=3x-3 to 2n=3x+3 in 1 to 4 months-old cultures and increased with the age of cultures with 2n=5x-l to 7x in cultures older than 6 months. Therefore, an alternative method was developed to reduce somaclonal variation in germinated somatic embryos, by using leaf from genetically stable plants (1-4 months-old cultures) as a source of explants for re-initiation of fresh embryonic cultures. RAPD finger printing of plantlets raised by this method revealed very little variation (6.15 %). Further improvement in somatic embryogenesis is required towards domestication of the plant using biotechnological method of propagation.