Evaluation of Abscisic Acid Analogs as Holding Agents for Bedding Plant Seedlings
The marketing period of nursery-raised bedding plant seedlings is limited by the loss of aesthetic quality associated with undesirable growth and/or excess moisture loss during storage and handling. Long-lasting synthetic analogs of abscisic acid (ABA) (8′-methylene ABA methyl ester and 8′-acetylene ABA methyl ester) were evaluated for their potential use in controlling growth and extending the marketing period of seedlings of tomato (Lycopersicon esculentum), snapdragon (Antirrhinum majus), and nasturtium (Tropelaum majus). ABA analogs, applied as root-dips, slowed moisture use and reduced seedling growth in a dosage-dependent manner with no significant phytotoxic effects over the short term. The nature and duration of the responses of the three test crops to the ABA analog treatments were similar. ABA analogs were more effective at reducing moisture use by tomato seedlings than regular ABA and also had fewer negative effects on plant appearance. Before ABA analogs can be recommended for commercial-scale use, their impact on long-term performance needs to be determined, along with an evaluation of their cost and safety relative to other plant growth retardants.