Research on physicochemical properties, microscopic characterization and detection of different freezing-damaged corn seeds

Seed freezing damage is an agricultural disaster. To explore how frostbite affects the growth and development of corn seeds, the germination conditions, and the biological indicators including the activities of related enzymes (SOD, POD, CAT, and AMS) of different frozen corn seeds (normal, −10 °C,10 h, and −20 °C,10 h) were measured. The texture of seed coat and the cell structure of seed embryo were observed by scanning electron microscope and transmission electron microscope respectively. The texture and cell structural changes reflect the influence of frostbite on corn seeds. To propose a quick, accurate and non-destructive method to identify the freezing-damaged corn seeds, near-infrared spectroscopy was used the identify the different frozen corn seeds. Different pretreatments, feature extraction methods and modeling methods were applied, result showed that in the case of standard normal variation pretreatment combined with principal component analysis feature extraction method and K-nearest neighbor model, 99.4 % and 100 % classification results of the training set and testing set were obtained respectively.