Type 2 Nondeep Physiological Dormancy in Seeds of Fraxinuschinensis subsp. rhynchophylla (Hance) A.E.Murray
Type 2 Nondeep Physiological Dormancy in Seeds of Fraxinuschinensis subsp. rhynchophylla (Hance) A.E.Murray
复制标题
白蜡树亚种种子的 2 型非深度生理休眠
作者：
Kangming An;Minghan Yang;Carol Caudle Baskin;Mingyue Li;Meiru Zhu;Chunjing Jiao;Haibo Wu;Peng Zhang
白蜡虫亚种。乔木是中国东北地区重要的用材树种，但对其种子休眠和萌发的研究较少，这阻碍了该树种的更新造林和保护。我们的目标是确定种子休眠的类别以及如何打破它。研究确定了种皮对水的渗透性，冷层积过程中胚胎发育的变化，以及在不同温度范围内冷层积对萌发的影响。种子是透水的，胚胎完全发育并填满了胚腔。5℃低温层积8周能有效打破种子休眠，说明种子具有非深度生理休眠(PD)。随着冷层积时间的增加，种子在低温(10℃和15℃)下萌发的能力增强，表明存在第二类非深层PD，在休眠-休眠期间萌发的最低温度降低。非休眠种子在25℃恒温(发芽率为63%)和35℃/25℃、30℃/15℃、25℃/20℃和20℃/10℃交变温度条件下(发芽率分别为66%、67%、65%和66%)，萌发率和发芽率均较高。为了生产幼苗，我们建议在15°C到30°C的温度下播种之前，在5°C下进行8周的冷层积。
Fraxinuschinensis subsp. rhynchophylla (Oleaceae), hereafter F. rhynchophylla, is an important timber species in northeast China; however, little is known about its seed dormancy and germination, which hinders regeneration of the species from seeds for reforestation and conservation. Our aim was to determine the class of seed dormancy and how to break it. Studies were conducted to determine the permeability of the seed coat to water, changes in embryo development during cold stratification and effects of cold stratification on germination over a range of temperatures. The seeds were water-permeable, and the embryo was fully developed and filled the embryonic cavity. Cold stratification at 5 °C for 8 weeks was effective in breaking dormancy; thus, we conclude that the seeds have nondeep physiological dormancy (PD). As cold stratification time was increased, the ability of seeds to germinate at low temperatures (e.g., 10 °C and 15 °C) increased, indicating the presence of Type 2 nondeep PD, in which the minimum temperature for germination decreases during dormancy-break. Nondormant seeds germinated to high percentages and rates at constant temperatures of 25 °C (germination percentage was 63%) and at alternating temperature regimes of 35 °C/25 °C, 30 °C/15 °C, 25 °C/20 °C and 20 °C/10 °C (germination percentage was 66%, 67%, 65% and 66%, respectively). To produce seedlings, we recommend 8 weeks of cold stratification at 5 °C before sowing the seeds at temperatures ranging from 15 °C to 30 °C.