ИСТИНА

The early indicator of seed aging is appearance of abnormal seedlings with morphological defects. A lot of aging air-dry seeds was subdivided to three fractions by using room temperature phosphorescence method. These fractions included strong seeds (fraction I) producing normal seedlings, weak seeds (fraction II) producing mainly abnormal seedlings, and dead seeds (fraction III). Fraction II seeds imbibe two times more rapidly than fraction I seeds. It is believed that accelerated imbibition results from membrane damage induced by lipid peroxidation. Lipid peroxidation products and glucose, a product of non-enzymatic hydrolysis of carbohydrate, were measured in powders of air-dry pea seed fractions by the method excluding water addition (thermochemiluminescence). The content of lipid peroxidation products was similar in both strong and weak seeds – the fact that excluded the possibility of lipid peroxidation to induce the transition of strong to weak seeds at early aging. Lipid peroxidation was activated only in dying seeds. It is worth noting that in fraction II seeds glucose content was higher and their water content was lower than in fraction I seeds. These facts indicated the operation of non-enzymatic hydrolysis, probably of oligosaccharides. As air-dry seeds lack free water the reaction hydrolytic utilized bound water. Therefore, the main cause of air-dry seed deterioration at early aging is non-enzymatic hydrolysis, whereas lipid peroxidation, the most commonly believed process, is not a decisive event.