Effects of concentration and treatment duration upon dwarf pea response to gibberellic acid root treatments in solution culture

• Published in: Plant and soil 1988-12, Vol.112 (2), p.279-287
• Main Authors: ANDERSON, S. J., JARRELL, W. M., FRANCO-VIZCAINO, E.
• Format: Article
• Language: English
• Subjects: Active sites; Agronomy. Soil science and plant productions; Biological and medical sciences; Chemical agents; Economic plant physiology; Fundamental and applied biological sciences. Psychology; Gibberellins; Growth and development; Growth regulators; Hormones; Internodes; Nutrient solutions; Peas; Plant physiology and development; Plant roots; Planting; Plants; Seedlings; Vegetative apparatus, growth and morphogenesis. Senescence
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/BF02140007

Gibberellic acid (GA₃) root treatments stimulated internode elongation of hydroponically grown dwarf pea seedlings (Pisum sativum L., cv. Little Marvel) when the GA₃ concentration in the solution was at least 2.9 µM. Both GA₃ concentration and the duration of the root-treatment period significantly affected internode elongation. This is attributed to a limited availability or saturation of active sites for gibberellin-induced cell elongation. The amount of GA₃ taken up through the roots in 1 day from a 29 μM GA₃ solution apparently equaled or exceeded the amount which could be metabolized during the first four days after treatment, although higher concenrations and longer treatment periods produced a more prolonged response, conceivably due to 1) initial saturation of gibberellin active sites, 2) storage of surplus gibberellin in the plant, and 3) subsequent utilization of the stored gibberellin. GA₃-induced stem elongation in hydroponically grown Little Marvel peas seemed to be limited initially by apparent saturation of active sites when the GA₃ concentration exceeded 29 μM.