The Brazilian Cerrado, a Neotropical savanna, is a fire-prone ecosystem where the ground layer biomass consists mainly of graminoids. However, as for other savannas, the effects of fire cues (such as smoke) on Cerrado grasses do not present a clear pattern, either for germination or seedling development. Smoke can stimulate different stages of the plant life cycle, which can alter the community and invasion processes. So far, most research on the subject focuses on germination, not addressing post-germinative phases, a sensitive stage of plant development. Here, we investigated the effect of smoke on a native (Echinolaena inflexa) and an invasive (Urochloa decumbens) grass species common in the Cerrado. We analysed germinative parameters and seedling mass and length after exposing the seeds to dry smoke for 5, 10, 15 or 20 min. Seedling development was assessed by measuring shoot and root systems after cultivating germinated seeds for 3, 7 or 15 d. Smoke did not affect germination percentages. However, fumigation reduced the mean germination time of both species and the germination onset of E. inflexa. U. decumbens had higher length values in all periods of cultivation, whereas mass values only surpassed that of E. inflexa at 15 d. Smoke exposure reduced the aboveground length of 7-d seedlings of U. decumbens, and mass of 15-d plants of both species. Also, smoke enhanced the root investment of the native and invasive species in different cultivation periods. Therefore, studying post-germinative parameters on seedling development may bring further insights into the smoke effects.

巴西塞拉多是一个新热带稀树草原，是一个容易发生火灾的生态系统，其地层生物量主要由禾本科植物组成。然而，对于其他稀树草原，火线索（如烟雾）对 Cerrado 草的影响并没有呈现出明确的模式，无论是对于发芽还是幼苗发育。烟雾可以刺激植物生命周期的不同阶段，从而改变群落和入侵过程。到目前为止，关于该主题的大多数研究都集中在发芽，而不是针对发芽后阶段，即植物发育的敏感阶段。在这里，我们研究了烟雾对原生（Echinolaena inflexa）和侵入性（Urochloa decumbens ）的影响) 塞拉多常见的草种。我们在将种子暴露在干烟中 5、10、15 或 20 分钟后分析了发芽参数和幼苗质量和长度。在将发芽的种子培养 3、7 或 15 天后，通过测量枝条和根系来评估幼苗的发育。烟雾不影响发芽率。然而，熏蒸减少了两个物种的平均发芽时间和E. inflexa的发芽时间。U. decumbens在所有栽培时期都有较高的长度值，而质量值仅在 15 d 时超过E. inflexa 。烟雾暴露减少了U. decumbens 7 天幼苗的地上长度，以及这两个物种的 15 天植物的质量。此外，烟雾增强了本地和入侵物种在不同栽培时期的根系投资。因此，研究幼苗发育的发芽后参数可能会进一步了解烟雾效应。