Physiological Responses to Wind‐ and Sandblast‐Damaged Winter Wheat Plants¹

Yield depression due to physical damage by wind and windblown soil (sandblast damage) is well known. The objective of this research was to determine if this yield depression was due to physiological changes within the plant or to the loss of viable plant tissue. Physiological responses of winter wheat ( Triticum aestivum L. em. Thell) to injury by a 20‐minute exposure to wind (13.4 m/sec), wind plus sand (5, 10, and 15 kg), and partial defoliation (removal of the distal 1/4 and 1/2 of each leaf) were evaluated. Net photosynthesis, dark respiration, ribulose‐l,5‐diphosphate (RUDP) carboxylase activity, total chlorophyll, dry weight, leaf area, and total nonstructural carbohydrates (TNC) were determined 1, 3, and 7 days after treatment. Dry‐weight production and accumulation decreased with increased plant injury. Reduced growth of sandblasted wheat seedlings is caused by loss of viable leaf tissue and physiological changes, which are mainly reduced photosynthesis and increased respiration. It is not clear from this study whether these changes result from partial defoliation, short‐term high‐intensity moisture stress, or a combination of both.