Samples were left undisturbed for at least 10 min for the L-1 or the L-2 test or at least 30 min for the L-3 test.
The L-2 test solution was prepared by adding 1.25 mL of L-2 buffer, 0.25 mL of methylene blue, 0.25 mL of acetone, 7.8 mg of dithiothreitol, and 0.25 mL of substrate solution for each sample.
An aliquot of 1.2 [micro]L of polyoxyethylenesorbitan mono-laurate (Tween 20) per sample for the L-1 or L-2 test or 2.4 [micro]L per sample for the L-3 test was added by using a pipette tip with the tip cut off.
The average reaction time for the L-2 test was [approximately equals] 5 min for individual seed chips, similar to the time reported by Suda et al.
The cost of the test solutions was approximately $0.01 per sample for the L-1 test, $0.09 for the L-2 test, and $0.02 for the L-3 test.
The dye for the L-1 and L-2 tests is methylene blue and for the L-3 test is [Beta]-carotene.
The dye for the L-1 or L-2 tests (200 [micro]M methylene blue) was prepared by adding 0.075 g of methylene blue to 1.0 L of distilled water in a screw-top bottle.