Influence of cold storage period and auxin treatment on the subsequent rooting of carnation cuttings

The influence of the duration of cold storage and a subsequent auxin treatment on the rooting of cuttings from three carnation cultivars ('Oriana', 'Elsy' and 'Virginie') was studied. When cuttings were stored for short periods (2 weeks), auxin (indole-3-butyric acid plus naphthaleneacetic acid) treatment stimulated the rooting in 'Oriana' and 'Elsy' but produced no effect in 'Virginie'. However, no significant auxin effect was observed in any variety when cuttings were stored for long periods (12 weeks), Increasing the storage period from 2 to 10 weeks (in 'Oriana') or to 8 weeks (in 'Elsy') was as effective as the auxin treatment in stimulating the rooting. The onset of rooting in untreated 'Virginie' cuttings was delayed as the storage period increased from 2 to 8 weeks. The stimulation of the rooting by auxin treatment or storage in 'Oriana' and 'Elsy' meant a reduction of about 4 days in the time required to reach optimal rooting. Neither the percentage of rooting nor the quality of rooted plants was modified at the end of the rooting period, irrespective of auxin treatment or storage. Changes in the endogenous auxin levels and auxin sensitivity during storage might account for the results obtained.