Granström A, Schimmel J
Department of Forest Ecology, Swedish University of Agricultural Sciences, S-901 83, Umeå, Sweden.
Oecologia. 1993 Jun;94(3):307-313. doi: 10.1007/BF00317103.
To analyse the potential reaction to firegenerated heat pulses, seeds of 12 species of plants and rhizomes of three species were exposed to elevated temperatures for 10 min. The tested material split into three groups with respect to heat tolerance: (1) the rhizomes, for which the lethal temperatures were in the range 55-59° C; (2) the seeds of most of the species tested, for which the lethal temperatures were in the range 65-75° C; (3) The seeds of two species of Leguminosae and three species of Geranium for which the lethal temperatures were around 100° C. For all three Geranium species and for one of the legume species, Anthyllis vulneraria, exposure temperatures above ca. 45° C resulted in dormancy release, and maximum germination occurred above 60-65° C. Speed of germination was little affected for most species, except after exposure to nearlethal temperatures, where it slowed down dramatically, although the seedlings emerging were healthy. We conclude that due to sharp temperature gradients in the soil during fire, differences in heat tolerance between species in most cases are not large enough to be a decisive factor in their post-fire colonising success. There are exceptions: the seeds of certain taxa that are impermeable to water in the dormant state, some of which have heat triggered germination.
为了分析植物对火灾产生的热脉冲的潜在反应，将12种植物的种子和3种植物的根茎暴露在高温下10分钟。测试材料根据耐热性分为三组：（1）根茎，其致死温度在55-59°C范围内；（2）大多数测试物种的种子，其致死温度在65-75°C范围内；（3）两种豆科植物和三种天竺葵属植物的种子，其致死温度约为100°C。对于所有三种天竺葵属植物和一种豆科植物黄花岩黄芪来说，暴露温度高于约45°C会导致休眠解除，最大发芽率出现在60-65°C以上。除了暴露在接近致死温度后发芽速度会大幅减慢外，大多数物种的发芽速度受影响较小，尽管长出的幼苗是健康的。我们得出结论，由于火灾期间土壤中温度梯度较大（温度急剧变化），大多数情况下物种之间耐热性的差异不足以成为它们火灾后定殖成功的决定性因素。也有例外情况：某些分类群的种子在休眠状态下不透水，其中一些种子会因受热而触发发芽。
