Ethanol production by hydrated seeds: A high resolution index of seed quality

Rapid seed quality tests are needed that are able to detect the early stage s of ageing. A test that employs the ratio of two measurements, in which on e response increases as seeds age and the other decreases, should provide a sensitive index for assessing quality. Changes in respiratory activity (me asured by ethanol production) were examined with respect to seed quality in cabbage (Brassica oleracea). Seeds were equilibrated at 70% relative humid ity and aged by incubation at 40 degrees C for 0, 7, 14, 21 or 28 d. A 48-h germination count and standard germination test were performed on each sam ple. Aqueous extracts were prepared from seeds hydrated for 24 h under aero bic or anaerobic conditions. Solid phase microextraction (SPME) followed by gas chromatography revealed ethanol, but not methanol in the extracts. For routine work, ethanol was analyzed from aqueous extracts using immobilized enzyme technology with alcohol oxidase. Ethanol production increased with ageing under aerobic conditions, while ethanol production decreased with ag eing under anaerobic conditions. The ratio of anaerobic to aerobic (ANA) et hanol production decreased substantially with mild ageing. The ANA ratio wa s shown to have excellent sensitivity and resolution for assessing seed qua lity of high quality lots.