THE EFFECTS OF 6-BENZYLAMINOPURINE AND GIBBERELLIC ACID ON POSTHARVEST PHYSIOLOGY OF LISIANTHUS (EUSTOMA GRANDIFLORUM) FLOWERS: II. INFLUENCE OF DOSE ON INFLORESCENCE ARCHITECTURE AND QUALITY
The quality of lisianthus cut flowers is diminished by response to gravity, premature chlorosis and poor anthocyanin development on young florets, among others. The objective of this study was to investigate the effects of 6-benzylaminopurine (BA) and/or gibberellic acid (GA3) on the quality and physiological changes in harvested lisianthus flowers. Harvested lisianthus flowers (60 cm) were pulsed with BA (0, 70, 140 or 210 µM) combined with GA3 (0, 5, 10 or 15 µM). Silver thiosulphate (STS) pulse and deionised water were used to compare the efficacies. The untreated control and solo BA or solo GA3 treatments displayed undesirable stage-wise (primary, thereafter secondary and tertiary florets, respectively, of the cyme-like inflorescence) opening of florets. Combined BA and GA3 treatments fully overcame the stage-wise floret opening behaviour. However, solo BA or GA3 were the most effective treatments for improving the floret size (P≤0.001) and maintaining chlorophyll content (P=0.001). Combined doses above 70 µM BA + 5 µM GA3 triggered inhibitory effects on chlorophyll content. Combined treatment with BA and GA3 significantly (P≤0.001) increased petal anthocyanin levels on young florets and (P≤0.001) reduced the number of bents on the pedicels of florets thus improving the inflorescence architecture via reduced response to gravity. Cytokinins and gibberellins are known to interact negatively and this was confirmed in chlorophyll and floret size, however, responses on other parameters suggested the contrary.
Musembi, N.N., Hutchinson, M.J. and Waithaka, K. (2015). THE EFFECTS OF 6-BENZYLAMINOPURINE AND GIBBERELLIC ACID ON POSTHARVEST PHYSIOLOGY OF LISIANTHUS (EUSTOMA GRANDIFLORUM) FLOWERS: II. INFLUENCE OF DOSE ON INFLORESCENCE ARCHITECTURE AND QUALITY. Acta Hortic. 1077, 65-74
cytokinin, gibberellin, hormonal crosstalk, gravitropism, plant growth regulator, chlorophyll, anthocyanin