This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Web of Science (11) Citing Articles via Google Scholar Google Scholar Articles by Klein, R. R. Articles by Wilson, R. F. Search for Related Content PubMed PubMed Citation Articles by Klein, R. R. Articles by Wilson, R. F. Agricola Articles by Klein, R. R. Articles by Wilson, R. F.

Articles

Effect of Osmotic Stress on Ion Transport Processes and Phospholipid Composition of Wheat (Triticum aestivum L.) Mitochondria

United States Department of Agriculture, Agriculture Research Service, Plant Stress and Water Conservation Unit, Texas Tech University, Lubbock, Texas 79409, United States Department of Agriculture, Agriculture Research Service, North Carolina State University, Raleigh, North Carolina 27650, Department of Crop Science, North Carolina State University, Raleigh, North Carolina 27650

The effect of osmotic stress on wheat (Triticum aestivum L.) mitochondrial activity and phospholipid composition was investigated. Preliminary growth measurements showed that osmotic stress (–0.25 or –0.5 megapascal external water potential) inhibited the rate of shoot dry matter accumulation while root dry matter accumulation was less sensitive. We have determined that differences in sensitivity to osmotic stress existed between tissues at the mitochondrial level. Mitochondria isolated from roots or shoots of stressed seedlings showed respiratory control and ADP/O ratios similar to control seedlings which indicates that stressed mitochondria were well coupled. However, under passive swelling conditions in a KCl reaction mixture, the rate and extent of valinomycin-induced swelling of shoot mitochondria were increased by osmotic stress while root mitochondria were largely unaffected. Active ion transport studies showed efflux transport by stressed-shoot mitochondria to be partially inhibited since mitochondrial contraction required the addition of N-ethylmaleimide or nigericin. Efflux ion transport by root mitochondria was not inhibited by osmotic stress which indicates that stress-induced changes in ion transport were largely limited to shoot mitochondria. Characterization of mitochondrial fatty acid and phospholipid composition showed an increase in the percentage of phosphatidylcholine in stressed shoot mitochondria compared to the control. Mitochondrial fatty acid composition was not markedly altered by stress. No significant changes in either the phospholipid or fatty acid composition of stressed root mitochondria were observed. Hence, these results suggest that a tissue-specific response to osmotic stress exists at the mitochondrial level.

This article has been cited by other articles:

				O. K. Atkin and D. Macherel The crucial role of plant mitochondria in orchestrating drought tolerance Ann. Bot., February 1, 2009; 103(4): 581 - 597. [Abstract] [Full Text] [PDF]

				J. J. Burke Evaluation of Source Leaf Responses to Water-Deficit Stresses in Cotton Using a Novel Stress Bioassay Plant Physiology, January 1, 2007; 143(1): 108 - 121. [Abstract] [Full Text] [PDF]