INFLUENCE OF NITROGEN FORM AND NH+4-N - NO-3-N RATIOS ON ADVENTITIOUS SHOOT FORMATION FROM PEAR (PYRUS-COMMUNIS) LEAF EXPLANTS INVITRO

The effect of various basal salts media, containing different nitrogen levels on in vitro adventitious shoot regeneration from leaf explants of 'Louise Bonne Panachee' and 'Seckel' pear (Pyrus communis L.) were investigated. Among the different basal salt formulae tested, Nitsch & Nitsch (1969) gave significantly better regeneration in most of the experiments. Shoot regeneration was altered with different NH4+-N/NO3--N ratios. The best regeneration was obtained when NH4+:NO3- was either 1:2 or 1:3 regardless of overall N concentration. In addition, these data show that NH4+ was essential for adventitious shoot regeneration from pear leaf explants on White's (1943) medium.