The understories of tropical forests comprise complex communities and can be divided into permanent understory, where the generally shade-tolerant plant growth forms are less developed in height, and transient understory, where young tree individuals are only temporarily present. Despite a high contribution to species richness in tropical forests, the understory is poorly studied. Here, we examined the species composition, richness, structure, diversity, and the relative contribution of growth forms in permanent and transient understories of gallery forests in the Brazilian Cerrado. A total of 211 species distributed into sixty-seven families and 153 genera were sampled. The most species-rich family was Rubiaceae, and Miconia was the genus with the highest species richness. The species Hildaea pallens had the highest importance in the forests. The best-represented growth forms were tree seedlings, followed by shrubs and lianas. The transient component of the understory in gallery forests was the most diverse. However, in terms of species relative cover, both transient and permanent understory species contributed equally to the understory structure, mainly due to the high cover of Poaceae species. Our study is the first to examine composition, structure, diversity, and growth forms in the permanent and transient understories of gallery forests. Study Implications: Our study is innovative in describing the plant community attributes of gallery forest understories in the Brazilian Cerrado. The understories of tropical forests comprise complex communities and can be divided into permanent and transient understory. The transient component of the understory in gallery forests was the most diverse, represented by seedlings and young tree specimens. However, in terms of species relative cover, both transient and permanent understory species contributed equally to the understory structure. Here, we provide evidence that may be useful to initiatives seeking to conduct ecological restoration and conservation of gallery forests in the Cerrado.

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RESUMO O tegumento e conteúdo de água das sementes podem interferir na sua tolerância a choques térmicos, assim como o seu ambiente de origem. Para testar essas possibilidades, sementes de Plathymenia reticulata e Stryphnodendron adstringens foram coletadas no norte do Estado de Minas Gerais (representando savana seca) e no nordeste do Estado do Mato Grosso (representando savana úmida) do bioma Cerrado, e suas respostas a choques térmicos de 110, 140 e 170 ºC por 2,5 minutos foram avaliadas sob diferentes condições; intactas, escarificadas, e embebidas após escarificação. Sementes escarificadas e embebidas germinaram mais rapidamente para ambas as espécies. Sementes de savana seca apresentaram menor teor de água inicial e germinação mais lenta para ambas as espécies, porém maior tolerância a choques térmicos que sementes de savana úmida. Sementes de P. reticulata não sobreviveram após tratamento de 140 ºC, mas sementes de S. adstringens de savana seca suportaram tratamento de 170 ºC, independentemente de estarem escarificadas e/ou embebidas. Conclui-se que sementes de P. reticulata são menos tolerantes a choques térmicos que sementes de S. adstringens, que sementes secas são mais tolerantes a choques térmicos que sementes embebidas, e que sementes de savanas secas são mais tolerantes a choques térmicos que sementes de ambientes úmidos.