Xue Xuzhang

Effect of wind speed on transpiration and biomass accumulation of potted amaranth.

By using pot experiment under greenhouse condition, the effect of wind speed on amaranth transpiration and biomass accumulation was analyzed at wind speed of 2.0 m·s-1, 1.0 m·s-1, 0.4 m·s-1 and 0.0 m·s-1. The study shows similar changes in transpiration rate and daily transpiration of potted amaranth at different wind speed. There exist no remarkable differences among the treatments. In general, transpiration rate and daily transpiration are maximum at 1.0 m·s-1, followed by 0.4 m·s-1 and the 0.0 m·s-1, the lowest at 2.0 m·s-1. Meanwhile, stepwise regression analyses show strongest positive correlation between transpiration rate and illumination intensity under different wind speed, followed by that between transpiration rate and temperature at 2.0 m·s-1. However, transpiration rate of other treatments has significant negative correlation with relative humidity. Daily mean temperature is a major factor affecting daily transpiration rate. The biomass accumulation curve of the potted amaranth shows that biomass accumulation is highest at 1.0 m·s-1 and lowest at 2.0 m·s-1. The effect of wind speed under greenhouse condition on above-ground fresh weight, under-ground fresh weight and root-shoot ratio of potted amaranth are very significant, highest at 1.0 m·s-1 and lowest at 2.0 m·s-1. Dry matter weight is obviously affected by wind speed, and is maximum at 1.0 m·s-1. The effect of wind speed on transpiration water consumption and water use efficiency is insignificant, but water use efficiency is maximum at 1.0 m·s-1 wind speed.