A procedure for the purification and quantitation of abscisic acid : and its application to a study of abscisic acid concentrations in needles of cold stored Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings

Graduation date: 1983A rapid and efficient procedure that required no partitioning was developed for the purification of abscisic acid (AbA) from the needles of Douglas-fir seedlings. Extracted needle pigments were removed by a\ud PVP column and the eluted AbA was concentrated on a DEAE column. The AbA was eluted from the DEAE column onto a C18 column with acetic acid. The AbA was eluted from the C18 column with methanol. AbA\ud purification was completed in 10 min and recoveries averaged 83%. Additional purification by a reverse-phase C18 UPLC after methylation and prior to quantitation was necessitated by the quantity of pigments\ud in Douglas-fir needles. HPLC purified the samples extensively. Overall, purification recoveries averaged 37%. AbA quantitation was\ud by gas chromatography with electron capture detector and using a 3% OV 101 column. The sensitivity limit of the detection was 20 pg.\ud Approximately 8 samples per day could be processed. The above procedure was applied to the study of the changes in concentrations of AbA in needles of lifted and stored Douglas-fir seedlings. Needle samples were taken from seedlings lifted in\ud November, January, and March and either planted immediately after lifting or stored at 4°C for 8 weeks in darkness or in light.\ud Seedlings were planted and time till bud break was monitored. March lifted seedlings had the highest concentrations of AbA while the November lifted seedlings had the lowest. At a given lifting time, the light-stored seedlings generally had the highest concentration of AbA while the non-stored and dark stored seedlings had lower but\ud similar AbA concentrations. The later lifted seedlings had a shorter time to bud break than the earlier lifted seedlings. Cold storage and light treatment during cold storage hastened time till bud break for\ud all three lifting dates. AbA concentrations in needles of Douglas-fir were negatively\ud related to dormancy and positively related to time till bud break or "good physiological state" of seedlings. These results suggest that AbA is acting as a stress hormone rather than a dormancy hormone. Concentrations of AbA might be considered to be an indication of the\ud seedlings' ability to resist or ameliorate environmental stress. Thus, it appears that monitoring AbA concentrations in the needles of Douglas-fir seedlings is a possible method for the determination of the "physiological state" of seedlings