The effect of short-term heat shock in root zone on gas exchange of Tradescantia pallida

Temperature stress is one of the most common abiotic stress in plant. Leaf gas exchange is on the first process that is effected by temperature. In order to investigate the effect of short-term heat shock in root zone on stomatal behavior and gas exchange on Trasescantia, this experiment was conducted at Faculty of Agriculture, Lorestan University. Roots were treated with three different temperatures (25, 35 and45 °C) for 10 min and stomatal behavior were measured. The result showed that aperture and photosynthesis rate were the highest in 35°C. As temperature increased to 35°C, photosynthesis rate and aperture area increased 7% and 24%, respectively, compared with those of control plants (25°C). However, as temperature increased to 45°C, transpiration rate and stomatal conductance decreased 40% and 14%, respectively, compared with those of control plants. Exposure of roots to 45°C for 30 min caused 72% reduction in photosynthesis rate. According to the results, root zone temperature significantly affect stomatal behavior, gas exchange and photosynthesis.