Silva Dias Luís, Pires Pereira Isabel, Soveral Dias Alexandra
Department of Biology, University of Évora, Ap. 94, 7000-554 Évora, Portugal.
Institute of Mediterranean Agricultural and Environmental Sciences, University of Évora, Ap. 94, 7000-554 Évora, Portugal.
Plants (Basel). 2019 Mar 12;8(3):63. doi: 10.3390/plants8030063.
Seeds of experience bursts of germination following fires. The effects of heat shock from 10 °C to 150 °C on seed germination were investigated by final germination plus the number of days required for germination to start and finish, and symmetry of cumulative germination. The occurrence of physical dormancy in seeds was investigated by a variety of methods, including imbibition, scanning electron microscopy (SEM) and light microscopy, and use of dyes. The significance of responses of seeds to fires was investigated essentially by abstracting existing literature and by using fire effects models and simulations. Parameters of germination were variously affected by heat treatments-positively in the range 80⁻100 °C, negatively above 130 °C. Non-dormancy was consistently found in about 30% of seeds but no evidence was obtained to support the existence of physical dormancy in the dormant fraction of seeds. Two complementary processes seem to be in place in seeds response to fire. A direct fire-driven increase in germination of virtually all seeds in response to the appropriate heat load produced by fire or, in the absence of such heat loads, the germination of the non-dormant fraction provided that above-ground vegetation burns.
经验的种子在火灾后会大量萌发。通过最终发芽率、开始发芽和完成发芽所需的天数以及累积发芽的对称性，研究了10℃至150℃的热休克对种子萌发的影响。通过多种方法研究种子中物理休眠的发生情况，包括吸胀、扫描电子显微镜（SEM）和光学显微镜以及染料的使用。通过提取现有文献并使用火灾影响模型和模拟，基本上研究了种子对火灾反应的重要性。热处理对萌发参数有不同影响，在80-100℃范围内呈正向影响，在130℃以上呈负向影响。在约30%的种子中始终发现无休眠状态，但未获得证据支持休眠种子部分存在物理休眠。种子对火灾的反应似乎存在两个互补过程。几乎所有种子对火灾产生的适当热负荷直接由火灾驱动萌发增加，或者在没有这种热负荷的情况下，如果地上植被燃烧，非休眠部分的种子会萌发。
