I. Staikidou et al., STIMULATION BY AUXIN AND SUCROSE OF BULBIL FORMATION IN-VITRO BY SINGLE LEAF CULTURES OF NARCISSUS, New phytologist, 127(2), 1994, pp. 315-320
Bulbil formation in vitro by single leaf explants from shoot clump cul
tures was investigated for Narcissus cultivars St Keverne and Hawera.
Single leaf explants (30-50 mm leaf with attached basal plate tissue)
formed bulbils very infrequently unless cultured on media containing b
oth auxin and a high concentration of sucrose whereas auxin was not ne
cessary for bulbil formation by shoot clump cultures. As well as she-w
ing much stronger stimulation by auxin, bulbil initiation and developm
ent were more strongly inhibited by BA in single leaf cultures than in
shoot clump cultures. Partitioning of dry matter into bulbils was gen
erally lower in single leaf cultures than in shoot clump cultures but
was more sensitive to growth regulators. Optimal sucrose and auxin con
centrations for bulbil development by single leaf cultures were invest
igated. Bulbil formation in the presence of NAA was strongly stimulate
d by 176 mM sucrose for both cultivars but there were genotypic differ
ences in auxin responses, St Keverne showing good bulbil development w
ith 0.54 mu M NAA, 5.4 mu M IAA and 5.4 mu M IBA and Hawera responding
only to 27 mu M IAA. It is concluded that single leaf cultures could
provide a simple system for investigation of the regulation of Narciss
us bulb initiation and development.