Effects of Short Periods of Anaerobic and Near‐Anaerobic Conditions on Water Uptake by Tobacco Roots¹

Abstract

Abstract Intact tobacco roots growing in nutrient solution spray in a sealed chamber were treated with mixtures of O 2 , N 2 , and CO 2 gases. Oxygen and water uptake by roots and plant stem diameter were recorded. Anaerobic treatments produced by flushing roots with N 2 or N 2 plus 21% CO 2 gases for 6 hours decreased water uptake 50% or more, but restoration of air to roots caused a rapid recovery of water uptake. Root injury was caused by both treatments, as evidenced by reduced oxygen uptake following each treatment. Gases with 1% or more oxygen had little or no effect on water uptake. Treatment gases containing up to 21% CO 2 had the same effect on water uptake as treatment gases without CO 2 . Oxygen deficiency appears to be the primary cause of the initial decrease in water uptake and wilting of tobacco subjected to poor root aeration.