Diversity of germination strategies and seed dormancy in herbaceous species of campo rupestre grasslands
Diversity of germination strategies and seed dormancy in herbaceous species of campo rupestre grasslands
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坎普鲁佩斯特雷草原草本植物萌发策略多样性和种子休眠
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
G. W. Fernandes
中科院分区：
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作者：
S. Stradic;Fernando A. O. Silveira;E. Buisson;K. Cazelles;Vanessa;Carvalho;G. W. Fernandes
火对植被的影响因大陆而异。然而，在新热带火灾多发草原上，火与种子萌发之间的关系仍然知之甚少，而它们的再生，特别是在强烈的人为干扰之后，对其保护具有挑战性。在本研究中，我们评估了15个优势草本植物物种的发芽策略多样性从新热带区海拔草原（当地称为坎波斯rupestres）。我们将种子暴露在几种与火有关的处理中。我们还比较了经常和火灾后的结果物种之间的发芽。最后，为了更好地理解种子休眠的地理分布和发生，我们对休眠类型的多样性进行了研究。发芽策略不同的家庭。Velloziaceae和Xyridaceae产生非休眠，快速发芽的种子。莎草科和禾本科表现出极低或零发芽，由于高比例的无活力或无胚种子。campo rupestre草原的种子是防火的，但没有证据表明火灾会在这个易受火灾影响的生态系统中引发发芽。虽然热和烧焦的木材没有促进发芽，烟雾提高发芽在一个草种，降低平均发芽时间，提高同步性在Xyridaceae和Velloziaceae。火通过刺激莎草科和禾本科植物的坐果对火后再生有积极的影响。这些物种产生更快的发芽种子，具有更高的发芽率和同步性相比，定期结实莎草科和禾本科物种。这种分散和再生的策略似乎是一种替代生产的种子发芽引发火灾。首次报道了新热带植物的几个分支中的生理休眠。我们的数据有助于推进对火在新热带草原再生中的作用的认识。
The effects of fire on the vegetation vary across continents. However, in Neotropical fire-prone grasslands, the relationship between fire and seed germination is still poorly understood, while their regeneration, especially after strong anthropogenic disturbance, is challenging for their conservation. In the present study, we assessed diversity of germination strategies in 15 dominant herbaceous species from Neotropical altitudinal grasslands (locally known as campos rupestres). We exposed seeds to several fire-related treatments. We also compared germination between regularly and post-fire fruiting species. Finally, we investigated the diversity of dormancy classes aiming at better understanding the biogeography and phylogeny of seed dormancy. Germination strategies varied among families. Velloziaceae and Xyridaceae produced non-dormant, fast-germinating seeds. Cyperaceae and Poaceae showed an extremely low or null germination due to a high proportion of unviable or embryo-less seeds. The seeds of campo rupestre grasslands are fire resistant, but there is no evidence that fire triggers germination in this fire-prone ecosystem. Although heat and charred wood did not promote germination, smoke enhanced germination in one grass species and decreased the mean germination time and improved synchrony in Xyridaceae and Velloziaceae. Fire had a positive effect on post-fire regeneration by stimulating fruit set in some Cyperaceae and Poaceae species. These species produced faster germinating seeds with higher germination percentage and synchrony compared to regularly fruiting Cyperaceae and Poaceae species. This strategy of dispersion and regeneration seems to be an alternative to the production of seeds with germination triggered by fire. Physiological dormancy is reported for the first time in several clades of Neotropical plants. Our data help advance the knowledge on the role of fire in the regeneration of Neotropical grasslands.