Anthers of Japanese persimmon (Diospyros kaki L. cv. Meotogaki) were cultured on MS medium containing zeatin (0 approximately 10 muM) in combination with IAA, NAA, or 2,4-D (0 approximately 10 muM).
Prolific callus formation was induced in the dark on MS medium supplemented with zeatin ( 1 approximately 10 muM)+ IAA or NAA (1 approximately 10 muM), or MS medium with zeatin 10 muM + 2,4-D (0.001 approximately 0.1 muM). Those cultured under a 16-hr.day - 1 photoperiod formed few calli.
The calli formed in the dark on MS medium supplemented with 10 muM zeatin + 1 muM IAA, 0.1 muM NAA, or 0.1 muM 2,4-D were subcultured in the dark on the same fresh medium. After 3-5 subcultures, the calli were subdivided and transferred onto three different kinds of differentiation medium, MS medium containing a) 10 muM zeatin+0.1 muM IAA, b) 10 muM zeatin + 0.01 muM NAA, or c) 10 muM zeatin + 0.01 muM 2,4-D, and cultured under a 16-hr-day-1 photoperiod to induce adventitious buds. Organogenetic potential of the calli, which had been induced and subcultured on MS medium containing IAA or NAA, increased with increasing number of subcultures, whereas those which had been cultured in the presence of 2,4-D formed few adventitious buds. IAA or NAA in the differentiation medium was also more effective for adventitious bud formation than was 2,4-D.
Both histological observations of the development of anther callus and chromosome counts of the root tip cells of regenerated plantlets revealed that the calli originated not from pollen grains but from vascular bundle in the anthers.
Eight of 18 plantlets regenerated from the anther-derived calli showed different malate dehydrogenase isozyme banding patterns from the pattern of the 'Meotogaki' tree growing in the field. However, all 12 plantlets regenerated from calli derived from leaf primordia of dormant buds of 'Meotogaki', had the same banding patterns as 'Meotogaki'. The potential use of the somaclonal variation observed in the regenerated plantlets from anther-derived calli is discussed in relation to the cultivar improvement of Japanese persimmon.