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Question:Fire and flood act as ecological filters on vegetation, either separately or combined, and cause morphological and physiological changes. Hence, they influence the composition and structure of plant communities. Since evidence strongly suggests that they are important filters operating in the system, we asked if fire, flood intensity, and their interaction could be related to variation in the functional traits of studied trees.Study Site: Pantanal, Mato Grosso do Sul, Brazil. Methods:We sampled 14 individuals (totaling 280) of the 20 most representative trees in 24 forest patches along the flooding gradient and measured functional traits related to allocation of resources and protection in response to these filters. We also assessed leaf and soil nitrogen, phosphorus, and potassium levels.Results: Along the flooding gradient, the studied tree species showed a tendency toward decreasing specific leaf area (SLA), as well as leaf nitrogen concentrations, whereas leaf thickness and leaf dry matter content (LDMC) increased. In burned areas, LDMC and leaf nitrogen exhibited the opposite tendency and decreased along the flooding gradient. Leaf thickness (LT) showed less increase in burned areas, while SLA had less decrease. Relative Bark Thickness (RBT) increased along the flooding gradient only after fire. Soil nitrogen decreased along the flooding gradient without an effect of fire. Conclusions:Since LDMC is a proxy of flammability, the probability of burning decreases after each fire event, while the most flooded environments become less fireprone. In burned environments, the differences in the allocation of resources (SLA and LT) diminish along the flooding gradient, indicating that leaf behavior is almost the same post-fire. RBT increases with increased flooding only after a fire, contributing to oxygen exchange during floods to protect the bark against fire. The interaction between fire and flood causes tree species to invest in structures for protection and resistance to fire, as well as retain nutrients. K E Y W O R D S ecological filters, environmental factors, floodplain, functional diversity, Pantanal 522 |

The study aimed to define the best conditions to conduct germination tests for Ormosia arborea seeds and assess the viability of seeds using the tetrazolium test. The germination tests were conducted at temperatures of 10, 15, 20, 25, 30, and 35 °C and alternating temperatures of 20-30 °C, in the presence or absence of light. For the tetrazolium test, seeds were immersed in tetrazolium solution 0.075%, at 35 °C for three hours, and then the viability was evaluated. It was verified that the seeds did not present absolute photosensitivity. The tetrazolium test was effective in separating the seeds into two categories concerning seed viability, viable and nonviable. It was concluded that O. arborea seeds germinate in the presence or absence of light in a wide range of temperatures. Temperatures of 25 and 30 ºC and alternating temperatures of 20-30 ºC are indicated to conduct germination tests. The tetrazolium test was effective in assessing seed viability.