Separating live from dead longleaf pine seeds: good and bad newsThis article is part of a larger document. View the larger document here.
Of all southern pine seeds, longleaf pine (Pinus palutris Mill.) are the most difficult to collect, process, treat, and store while maintaining good seed quality. As a result, interest in techniques for separating filled dead from live longleaf pine seeds has developed. The good news is that new technologies are becoming available to evaluate seed quality, but the bad news is that they seem to have limited application to longleaf pine. Tests suggest that incubating, drying, and separating, chlorophyll fluorescence, and near infrared techniques do not help improve longleaf pine seed quality. The incubating-drying-separating method is inefficacious because variability in the seed coat wing stub affects seed flotation. The chlorophyll fluorescence method measures changes in chlorophyll content as seeds mature or are damaged, but such changes do not seem to occur in pine seeds. The near infrared method seems to offer the best potential. The use of near infrared scanning technologies can determine changes in seed constituents, but we have not been able to determine which measurable seed constituents may change as viability declines.