Somatic embryogenesis in cotyledon cultures of tea(Theasinensis, L.)

Abstract

Summary A procedure to induce somatic embryos from cotyledons of tea seeds is described. Embryogénie culture was obtained from 70% of tender cotyledons (diameter 3-8 mm, with light brown and yellow seed coat) cultured on Murashige and Skoog’s (MS) basal medium, supplemented with 2,4-D (0.5 mg I-1) and kinetin (0.05 mg I-1). A gradient of response to form embryogenic culture was obtained with maturity of the seeds (cotyledons). More large compact, bulged tissues of variable shapes and sizes were formed in embryogenic culture, when the 2,4-D concentration was increased in the medium. However, these tissues when cultured separately on a medium low in 2,4-D and kinetin, produced pro-embryonic cell masses and, eventually, plants. Masses of globular embryos formed in embryogenic culture; these retained their growth and morphogenic ability in a maintenance medium, and on transfer to a hormone-free or a medium containing kinetin (0.05 |xg I-1) 30% matured to form heart to torpedo shaped embryos. Of these 40% readily germinated on half-strength MS medium supplemented with kinetin (0.05 mg I'1), glucose (1.5%) and activated charcoal (0.2%) to form complete plants. Morpho-histological evidence suggests that somatic embryos developed directly from cotyledon cells.