Exogenous Applications of Benzyladenine and Gibberellic Acid Inhibit Lower-leaf Senescence of Geraniums during Propagation
Year: 2013
Type: article
Abstract: After postharvest shipping, the lower leaves of zonal geranium ( Pelargonium × hortorum ) cuttings often turn chlorotic and necrotic during rooting in a propagation environment. Our objective was to quantify the efficacy of spray applications of the plant growth regulators (PGRs) benzyladenine (BA) and/or gibberellic acid (GA) at various stages in propagation to reduce lower-leaf senescence and evaluate effects on subsequent rooting. In Expt. 1, cuttings of ‘Patriot White’ geraniums were harvested and treated with BA (2.5 or 5.0 mg·L −1 ), BA + GA 4+7 (2.5 or 5.0 mg·L −1 each), or GA 3 (0.5 or 2.0 mg·L −1 ) either before or after a 2-day storage period simulating commercial shipping. Post-shipment application of all PGRs eliminated leaf yellowing compared with cuttings treated pre-shipment, but rooting was inhibited. In Expt. 2, the promotion of rooting from a rooting hormone preceding treatment with BA (1.25 to 5.0 mg·L −1 ), BA+GA 4+7 (1.25 to 5.0 mg·L −1 each), or GA 3 (0.25 to 2.0 mg·L −1 ) was evaluated on ‘Patriot White’ geranium cuttings after a 2-day simulated shipping. Applying rooting hormones increased the percentage of fully rooted cuttings treated with BA and/or GA from 16.4% to 51.8%. In Expt. 3, cuttings of different geranium cultivars from a commercial producer varied in susceptibility and suppression of leaf yellowing after BA + GA 4+7 applications. We conclude that foliar applications of BA + GA 4+7 can suppress lower-leaf senescence and rooting during propagation of some geranium cultivars, and the inhibition of rooting can be at least partially overcome with an application of rooting hormone.
Source: HortScience
Language: English
Subfield: Plant Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: gold
Estimated APC paid: $3,000
OpenAlex ID: W2405997823