Effect of Acid Treatment of Plant Cuticles on Sorption of Selected Auxins

• Published in: Plant physiology (Bethesda) 1987-03, Vol.83 (3), p.652-656
• Main Authors: Warren E. Shafer, Bukovac, Martin J.
• Format: Article
• Language: English
• Subjects: Acid treatment; Agronomy. Soil science and plant productions; Animal cuticle; Auxins; Biological and medical sciences; Chemical agents; Confidence interval; Economic plant physiology; Epoxy compounds; Fruits; Fundamental and applied biological sciences. Psychology; Growth and development; Growth regulators; Peppers; Plant cuticle; Plant physiology and development; Plants; Sorption; Vegetative apparatus, growth and morphogenesis. Senescence
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.83.3.652

Sorption characteristics of 2-(1-naphthyl)acetic acid (NAA), 2-(1-naphthyl)acetamide (NAAm), and 2,4-dichlorophenoxyacetic acid (2,4-D) were determined for cuticles enzymically isolated from mature tomato (Lycopersicon esculentum Mill. cv Sprinter) and pepper (Capsicum annuum L.) fruit. Sorption equilibrium for NAA and 2,4-D by tomato cuticular membranes (CM) and dewaxed cuticular membranes (DCM) was achieved within 24 hours at 25°C. The average K (partition coefficient) values for NAA in tomato CM and DCM were 166 and 204, respectively, whereas the corresponding K values for 2,4-D were 292 and 383, respectively. Sorption equilibrium for 2,4-D and NAA in pepper cuticles was not achieved after 18 and 63 days, respectively. Sorption equilibrium for NAAm in tomato and pepper CM and DCM was attained within 48 hours. Acid pretreatment (2.0 N HCl, 10 minutes) had no effect on NAA, 2,4-D, or NAAm sorption by tomato CM and DCM, or on NAAm sorption by pepper CM and DCM. Acid pretreatment of pepper CM and DCM led to slightly lower $K^{\text{pH}}$ (apparent partition coefficient) values for both NAA and 2,4-D. More significantly, sorption equilibrium for NAA and 2,4-D in pepper CM and DCM was achieved within 24 hours after acid treatment.