Abstract
Rice Plants (Oryza sativa L.) at different stages after heading were treated with artificial winds of 0 to 15 m/s, with and without an artificial rain. Flower fertilization was clearly inhibited by winds over 4 m/s. Rainy wind, however, did not cause much injury. Brown-discolored kernels were caused by wind at the flowering stage. Occurrence of milky white kernel, however, was promoted by winds at 14-21 days after heading (DAH). These injured kernels increased with strengthened wind. Wind accompanied by rain, on the other hand, caused injured kernels to a lesser extent. Transpiration rate of rice spikelet was highest just after heading. It slightly dropped around 7 DAH and increased again in the mid-stage of kernel development and decreased thereafter. The stages of high rate transpiration coincided with stages most susceptible to wind injury. The rate of transpiration was accelerated with increased wind velocity especially in earlier stages. It is concluded therefore that most of the wind injuries seem to be triggered mainly by a temporary water stress occured in a panicle or in each spikelet. Rain was thought to be effective to lessen wind injury through protecting spikelets from their water loss.
