2.3 Distribution of ROS inside barley seed cell
ROS (superoxide radical)can be visualized as deposits of dark-blue insoluble formazan com-pound using microscope spectrophotometer (MSV-5000, JASCO Co. Ltd., Japan). The mi-croscope spectrophotometer gave the UV-visable spectra, and spectral analyses were done on the small area of the samples. The distribution of ROS inside barley seed cell was deter-mined with fixed wavelength measurements. The difference of absorbance values at wave-length 560nm and 700nm represented the amount of ROS at each location. The absorbance value at 560nm can be used to represent the amount of dark-blue formazan. What’s more, the spectral background influence caused by impurities or radiation scattering can be re-duced by way of obtaining the absorbance difference at wavelengths 560nm and 700nm In order to know the distribution of ROS in the sample, the measurement covered the entire sample. For the first sliced sample and the second sliced sample, the numbers of measure-ment dots were about 100 and 325 respectively. The diameter of each measurement dot was 30μm.