Rapid Isolation and Measurement of Adenosine Triphosphate Levels in Corn Embryos Germinated at Suboptimal Temperatures

Abstract

The trend towards earlier planting dates and conservation tillage systems in corn (Zea mays L.) production has prompted interest in accurate methods for predicting cold tolerance in germinating seedlings. Measurement of nucleotide phosphate levels in germinating seed has been proposed as one such method, but has proven to be a tedious procedure to apply to plant materials. A nucleotide extraction technique was combined with high performance liquid chromatography (HPLC) and applied to the measurement of adenosine triphosphate (ATP) in germinating corn embryos. Embryo ATP concentrations were determined for seed lots of two corn hybrids imbibed over a 96‐h period at two temperatures, 10 and 20 °C. The lower temperature reduced ATP levels and accumulation rates for both cultivars. Differences in the embryo ATP concentrations of the respective hybrids were apparent after 32 h of imbibition at 10 °C. Differences in the ATP accumulation rate of those embryos were detectable 4 to 16 h into the germination process. Significantly lower quantities of ATP in one hybrid (Dekalb‐Pfizer XL 72B) germinated at 10 °C for 64 h were associated with a corresponding reduction in cold‐test germination percentage of that seed. Measurement of embryo ATP levels for six additional hybrid seed lots after 64 h of germination at 10 °C revealed significant variations in ATP concentration. Correlation of embryo ATP levels and cold‐test germination percentages with the field performance of these hybrids indicated that embryo ATP levels were a more reliable predictor of cold tolerance than the cold germination test.