Response of Wheat (Triticum aestivum) Seedlings to Mechanical Stress

Two varieties of winter wheat (Triticum aestivum), Blue Boy and Arthur, were cultured in plastic dishes in complete darkness or in dim light. Mechanical stimulation was administered by shaking the dishes laterally, by hand, at 1-2 cycles/s twice a day for 1 or 2 min. Blue Boy, a variety with excellent resistance to lodging, responded to the treatment by a significant reduction in shoot length, whereas shoot growth in Arthur, a variety more susceptible to lodging, was not significantly reduced. Blue Boy seedlings appear to be very sensitive to mechanical stress, since the culture procedure minimized other mechanically induced stimuli, such as alteration in water relations, physical contact phenomena, wounding, and geotonus.