The Changes of Ultraweak Bio-chemiluminescence from Germinating Soybean in the Wounding Defense Response

摘要

Ultra-weak bio-chemiluminescence (UBC) from germinating soybean (Glycine max L. Merr) cotyledon under mechanical wounding was observed by a high sensitive single photon counter (SPC) device. SPC measuring results showed that the UBC intensity of wounding green cotyledon was very high firstly and reached to a stationary state after about 5 minutes. Wounding-induced emission could be suppressed by wounding treatment with sodium azide. While the intensity increase of the wounded etiolated soybean cotyledon was less than the green one. Deuterium oxide both amplified the emission intensity of green and etiolated. Singlet oxygen (~1O_2) is a main cause of the emission during the wounding phase. We suggested that the main process was probably that chloroplast and mitochondria damage at the wounded place and leaded to ROS generation, such as H_2O_2, ~1O_2 etc. The electronic excitation energy transfered from the excited molecules by ROS to Chl-a in the thylakoid membranes by way of relatively high quantum yields, so the intensity of UBC in the wounded soybean green cotyledon was obviously higher than in the wounded etiolated soybean cotyledon.