Wheat Response to Short-term Heat Stress and to Soil Oxygen Stress at Three Stages of Growth1
- Robert E. Sojka,
- H. A. Joseph and
- L. H. Stolzy2
Wheat (Triticum aestivum L.) was grown under controlled environmental conditions for 47 days in two experiments to examine responses to low aeration beginning at various stages of growth, and to determine whether an interaction between temperature and soil aeration status is measurable in wheat. In both experiments oxygen was eliminated from the soil beginning at three different times in the growth cycle. In the second experiment the wheat was subjected to 36 hours of heat stress (42 C) on the 23rd day of growth.
There was a trend toward greater water use with low soil aeration. The root:shoot ratio was significantly decreased by poor aeration in the experiment without heat treatment; all three low-aeration treatments exhibit essentially the same root:shoot ratio despite different treatment starting times, which indicates that the duration of the low oxygen treatment necessary to alter the root:shoot ratio is relatively short. Interaction of low aeration and heat stress sharply reduces root weight and increases water use per dry weight plant tissue produced, with the effect generally more dramatic with low aeration for longer periods of time. After only a brief period of treatment all characteristics measured, except root:shoot ratio, were significantly affected by heat stress. The effects are partially interpreted in terms of increased respiration rate, leading to degradation of cytoplasm as a result of induced oxygen scarcity.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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