Leaf Water Adjustment and Maintenance in Hard Red Winter Wheat
- R. W. Gesch,
- D. G. Kenefick and
- J. A. Koepke
Tissue water content is an important determinant in freeze survival of winter wheat. Research was conducted to measure the variation in tissue water retention during drought stress of hard red winter wheat (Triticum aestivum L.) cultivars differing in potential for freeze resistance expression but without induction by cold acclimation. Tissue water status was determined on Leaf 3 of several cultivars grown in a greenhouse. The plant growth period was 20 d, followed by drought stress imposed by withholding water. Water, solute, pressure potentials, cell volumetric modulus, and osmotic adjustment evaluations were determined using the pressure volume technique. Osmotic adjustment was attributed to carbohydrate accumulation by evaluating solute potential of plants grown at varied durations of natural daylength. Greater tissue water retention was demonstrated for freeze-susceptible compared with freeze-resistant cultivars when subject to drought stress, in the absence of induction by cold acclimation. The significance of differential tissue water retention among these ecologically divergent cultivars could be related to an environmental sensing response, or a feature contributing directly to variance in freeze survival.
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