Effect of Wind on Plant Respiration

Various plant species were placed in a 13.5 liter belljar equipped with a motor-driven fan directly above the plants. Air was continually circulated from the belljar through an infrared CO₂ analyzer at the rate of 1.5 1/min. Species tested included Triticum aestivum, Hordeum vulgare, Avena sativa, Zea mays, Sorghum vulgare, Phaseolus vulgaris, Glycine max, Pisum sativum, and Magnolia grandiflora. Increases in respiration of shoots or intact plants were detected at windspeeds of 3.6 m/s and above. All species responded in a similar fashion with increases in respiration of 20 to 40% being typical at a windspeed of 7.2 m/s which is similar to windspeeds under many natural conditions. The respiration rate returned to the initial rate within a short time after the wind had stopped. In Magnolia a sustained elevated respiration rate was measured over an exposure period of 3 hours to a wind velocity of 7.1 m/s. In some experiments flutter of the leaves was prevented but the respiration rate of bean and Magnolia was still elevated in the wind. This would suggest that the response is subcellular and not due to gross movement of the leaf itself. It is suggested that such an elevated respiration rate (maximum increase measured was 56%) might be expected to interfere with net assimilation and may be responsible for lower yields obtained in windy regions.