PLANT PHYSIOLOGY , Vol 105, Issue 1 61-67, Copyright © 1994 by American Society of Plant Biologists

ENVIRONMENTAL AND STRESS PHYSIOLOGY

Hypoxic Induction of Anoxia Tolerance in Roots of Adh1 Null Zea mays L

J. R. Johnson, B. G. Cobb and M. C. Drew
Department of Horticultural Science, Texas A&M University, College Station, Texas 77843-2133

Seedlings of alcohol dehydrogenase 1 null mutants (Adh1-) of Zea mays L., which fail to synthesize alcohol dehydrogenase 1 (ADH1) isozymes, were hypoxically acclimated by 18 h of exposure to an atmosphere of 4% (v/v) O2 in N2 at 25[deg]C. Their ability to tolerate subsequent anoxia by exposure to anaerobic (O2-free) conditions was compared with that of unacclimated seedlings that were transferred immediately from an atmosphere of 40% (v/v) O2 to anaerobic conditions. Only 10% of the root tips of unacclimated seminal roots survived 6 h of anoxia, whereas 70% of the hypoxically acclimated root tips were viable at 24 h. During anoxia, acclimated root tips had enhanced ADH activity compared with unacclimated root tips, through induction of Adh2. Despite this, enzyme activity was still only about 5% that of acclimated, wild-type root tips and about half that of unacclimated, wild-type root tips. During anoxia, acclimated Adh1- root tips showed a higher rate of anaerobic respiration and ethanol production, greater concentrations of ATP and total adenylates, and a greater adenylate energy charge compared with unacclimated root tips. These results suggest that although enhanced ADH activity may have raised fermentation rates in acclimated Adh1- tissues and thereby contributed to energy metabolism and viability, the high levels of ADH activity inducible in acclimated, wild-type maize root tips appear to be in excess of that required to increase rates of fermentation.

This article has been cited by other articles:

				B. R. Benz, J. M. Rhode, and M. B. Cruzan Aerenchyma development and elevated alcohol dehydrogenase activity as alternative responses to hypoxic soils in the Piriqueta caroliniana complex Am. J. Botany, April 1, 2007; 94(4): 542 - 550. [Abstract] [Full Text] [PDF]

				K. P. Ismond, R. Dolferus, M. De Pauw, E. S. Dennis, and A. G. Good Enhanced Low Oxygen Survival in Arabidopsis through Increased Metabolic Flux in the Fermentative Pathway Plant Physiology, July 1, 2003; 132(3): 1292 - 1302. [Abstract] [Full Text] [PDF]

				O. Kursteiner, I. Dupuis, and C. Kuhlemeier The Pyruvate decarboxylase1 Gene of Arabidopsis Is Required during Anoxia But Not Other Environmental Stresses Plant Physiology, June 1, 2003; 132(2): 968 - 978. [Abstract] [Full Text] [PDF]

				H. Kato-Noguchi Abscisic acid and hypoxic induction of anoxia tolerance in roots of lettuce seedlings J. Exp. Bot., November 1, 2000; 51(352): 1939 - 1944. [Abstract] [Full Text] [PDF]

				H.-J. Chung and R. J. Ferl Arabidopsis Alcohol Dehydrogenase Expression in Both Shoots and Roots Is Conditioned by Root Growth Environment Plant Physiology, October 1, 1999; 121(2): 429 - 436. [Abstract] [Full Text]

				M. H. Ellis, E. S. Dennis, and W. James Peacock Arabidopsis Roots and Shoots Have Different Mechanisms for Hypoxic Stress Tolerance Plant Physiology, January 1, 1999; 119(1): 57 - 64. [Abstract] [Full Text]

				Y. Zeng, Y. Wu, W. T. Avigne, and K. E. Koch Differential Regulation of Sugar-Sensitive Sucrose Synthases by Hypoxia and Anoxia Indicate Complementary Transcriptional and Posttranscriptional Responses Plant Physiology, April 1, 1998; 116(4): 1573 - 1583. [Abstract] [Full Text]