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A simple, quick and nondestructive test method has been developed for determining Brassicaceae seed viability with single seed using resazurin reagent (RR) which was made by resazurin and yeast mixture. The color of the RR was changed from blue to pink or colorless when the aged seeds are soaked in the RR solution for 4 hours at 35 . Seed soaking system was developed using 96-well plate and absorbance of the RR was measured at 570 nm with a multi-plate reader. Radish (Raphanus sativus L.) seeds were artificially aged to create seven contrasting levels of viabilities. The relationships between the germination percentage of the radish seeds and the absorbance, and percentage of blue or colorless fractions of the soaked RR were appeared to have very high correlations in linear regression depending on the viability levels. The blue color fraction contained a high percentage of the normal seeds, while pink or colorless fraction contained high percentage of abnormal and dead seeds. Six lots of naturally aged Brassicaceae seeds were tested using the RR to observe an actual capability of quality assessment for intact seeds. A model equation has been developed for predicting germination percentage of the seeds by the color fractions of the soaked RR from the intact six Brassicaceae seed lots. The equation was found to have high prediction accuracy of 98.2%. This method is very quick and simple to use with a high accuracy for determining the quality of Brassicaceae seeds nondestructively.

The release of volatiles from aged radish (Raphanus sativus L., var. Yechanmoo) seeds and from ethanol was evaluated using the resazurin reagent (RR, solution of resazurin and yeast mixture). The primary volatile released from the aged radish seeds was identified as ethanol, but no volatiles from non-aged seeds were detected by solid phase microextraction (SPME) followed by GC-MS analysis and ethanol standard confirmation. The volatiles from aged radish seeds and from ethanol changed the color of the RR from blue to pink after 8-10 hours of incubation at 35 , and the absorbance of the RR was read at 570 nm. When ethanol was diluted with the RR at concentrations ranging from 0 to 10,000 ppm, the absorbance and ethanol concentrations were found to be negatively correlated in the linear regression analysis with r 2 = 0.91. For the seed test, the aged and non-aged radish seeds were soaked individually in the RR using a 96-well plate and incubated at 35 for 4 hours. The absorbance of the RR soaked non-aged seeds did not change; however, the absorbance of the aged seeds rapidly decreased with incubation time. Also, the visual color of the RR soaked aged seeds visibly changed from blue to pink after two hour of incubation and was colorless after four hours of incubation. The color changes of the RR could be attributed to the fact that ethanol accelerated respiration of the yeast and resorufin was produced through the reduction of resazurin. In conclusion, RR was shown to be a highly sensitive reagent for the detection of volatiles (mainly ethanol) released from aged radish seeds and could be used to simply, rapidly and nondestructively classify the viable and non-viable seeds.Additional key words: resazurin reagent, seed quality, solid phase microextraction (SPME), volatile, yeast Hort. Environ. Biotechnol. 53(1):66-71. 2012.

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