Effect of exogenous abscisic acid on proline dehydrogenase activity in maize (Zea mays L.)

• Published in: Plant physiology (Bethesda) Vol. 99; no. 2; pp. 762 - 764
• Main Authors: Dallmier, K.A. (Iowa State University, Ames, IA), Stewart, C.R
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Physiologists 01.06.1992
• Subjects: abscisic acid; ACIDE ABSCISSIQUE; ACIDO ABSCISICO; ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; Agronomy. Soil science and plant productions; Biological and medical sciences; Communications; Corn; Crop harvesting; Dehydration; Dehydrogenases; Drought; Enzymes; Fundamental and applied biological sciences. Psychology; Oxidation; OXIDORREDUCTASAS; OXYDOREDUCTASE; Plant physiology and development; Plant roots; Plants; PLANTULAS; PLANTULE; PROLINA; PROLINE; proline dehydrogenase; RELACIONES PLANTA AGUA; RELATION PLANTE EAU; Seedlings; seeds; stress; water; Water and solutes. Absorption, translocation and permeability; ZEA MAYS; Monocotyledones; Zea mays; Enzyme; Environmental factor; Cereal crop; Stress; Enzymatic activity; Gramineae; Drought resistance; Angiospermae; Abscisic acid; Plant growth substance; Spermatophyta; Biological accumulation; Drought; Proline dehydrogenase
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.99.2.762

Plant responses to drought stress include proline and abscisic acid (ABA) accumulation. Proline dehydrogenase (PDH) (EC 1.4.3) is the first enzyme in the proline oxidation pathway, and its activity has been shown to decline in response to water stress (PJ Rayapati, CR Stewart [1991] Plant Physiol 95: 787-791). In this investigation, we determined whether ABA treatment affects PDH activity in a manner similar to drought stress in maize (Zea mays L.) seedlings. Four exogenous ABA treatments (0, 11, 33, and 100 micromolar ABA) were applied to well-watered maize seedlings. Mitochondria were isolated and PDH was solubilized using Nonidet P-40. PDH activity was measured by the reduction of iodonitrotetrazolium violet under proline-dependent conditions. There was no effect of ABA on PDH activity at 33 and 100 micromolar ABA, but there was a 38% decline at 11 micromolar. This decline was less than the 69% reduction in activity under drought stress. Endogenous ABA determinations and plant growth rate showed that ABA entered the plant and was affecting metabolic processes. ABA treatments had a small effect on shoot and root proline concentration, whereas drought stress caused a 220% increase in root tissues. We conclude that ABA is not part of the pathway linking drought stress and decreased PDH activity