Shoot Regeneration from Leaf Mesophyll Protoplasts of Wild Pear ( Pyrus communis var. Pyraster L.)

Abstract

Leaf mesophyll protoplasts of wild pear ( Pyrus communis var. Pyraster L.) were successfully isolated from both field and in vitro grown plant material. Protoplast yields were greatly affected by the donor material. As much as 6.08±0.79 × 10 6 protoplasts per g fresh weight were isolated when in vitro grown leaves were used, whereas with field material both yield (2.56 × 10 6 protoplasts/g fresh weight) and reproducibility of results (S.D. = 1.03 × 10 6 prots/g fresh weight) were reduced. Cell colonies were recovered and subcultured to obtain callus proliferation (half-strength MS salts with NAA and BAP at 1.0 mg · l -1 each), from which shoots were regenerated upon further subcultures on a full strength MS formula supplemented with 0.1 mg · l -1 IBA and 1.0 mg · l -1 BAP. Only limited rooting of the protoplast derived shoots has been achieved so far.