The Effect of Wind on Grasses

Festuca arundicacea and Lolium perenne were grown in a controlled-environment wind tunnel at high (7-4 m s-1) or low (1-0 m s-1) windspeed. The rate of leaf extension was markedly reduced at the high windspeed. This effect could not be attributed to water stress, for, although the leaf conductance increased with exposure to high wind, no effect on leaf water potential was detected. Nor was the rate of photosynthesis affected when the windspeed was changed. Moreover, concen trations of ethylene in the wind tunnel were too low to explain the observations. It is suggested that mechanical stimulus itself may have caused the reduction in leaf growth rate.