Sondheimer E, Tzou D S, Galson E C
Chemistry Department, State University College of Forestry at Syracuse University, Syracuse, New York 13210.
Plant Physiol. 1968 Sep;43(9):1443-7. doi: 10.1104/pp.43.9.1443.
Dormant seeds from Fraxinus species require cold-temperature after-ripening prior to germination. Earlier, we found that abscisic acid (ABA) will inhibit germination of excised nondormant embryos and that this can be reversed with a combination of gibberellic acid and kinetin. Using Milborrow's quantitative "racemate dilution" method the ABA concentration in 3 types of Fraxinus seed and pericarp were determined. While ABA was present in all tissues, the highest concentration was found in the seed and pericarp of dormant F. americana. During the chilling treatment of F. americana the ABA levels decreased 37% in the pericarp and 68% in the seed. The ABA concentration of the seed of the nondormant species, F. ornus, is as low as that found in F. americana seeds after cold treatment. Experiments with exogenously added ABA solutions indicate that it is unlikely that the ABA in the pericarp functions in the regulation of seed dormancy. However, the ABA in the seed does seem to have a regulatory role in germination.
白蜡树种的休眠种子在萌发前需要低温后熟。此前，我们发现脱落酸（ABA）会抑制离体非休眠胚的萌发，而赤霉素和激动素的组合可以逆转这种抑制作用。使用米尔博罗的定量“外消旋体稀释”方法测定了3种白蜡树种子和果皮中的ABA浓度。虽然所有组织中都存在ABA，但在休眠的美国白蜡树的种子和果皮中发现的浓度最高。在美国白蜡树的低温处理过程中，果皮中的ABA水平下降了37%，种子中的ABA水平下降了68%。非休眠物种欧洲白蜡树种子的ABA浓度与美国白蜡树种子经过低温处理后的浓度一样低。外源添加ABA溶液的实验表明，果皮中的ABA不太可能在种子休眠调节中起作用。然而，种子中的ABA似乎在萌发中具有调节作用。
