Protective traits of aboveground buds in Duguetia furfuracea (A.St.-Hil.) Saff. (Annonaceae) from the Cerrado stricto sensu

Abstract

The Cerrado, the most biodiverse neotropical savanna, is characterized by recurrent fires, light intensity, seasonal drought, and nutrient-poor soils, conditions that exert strong selective pressures on vegetation. In this context, the endemic species occurring in this region exhibit diverse strategies to cope with these varied natural disturbances. Resprouting acts as the key trait for natural regeneration and is heavily influenced by a bud bank. The number and degree of protection of these meristematic structures determine the effectiveness of post-disturbance resprouting. Understanding the different protective mechanisms related to these structures enriches our knowledge of how native species adapt to the current challenges faced in fire-prone ecosystems. Here, we provide a detailed anatomical description of the apical and nodal buds of D. furfuracea, a species occurring in grassland formations of the Brazilian Cerrado. For this, the apical bud and the three subsequent nodal regions were collected and analyzed under light microscopy, histochemical analysis, fluorescence microscopy and scanning electron microscopy (SEM). Our analyses reveal that aerial buds are consistently enclosed by thick, inverted leaf primordia, densely covered by lepidote and stellate trichomes with thick cell walls. The morphology and wall thickening of these trichomes are consistent with a putative role as a mechanical and optical barrier, as proposed for similar trichomes in other angiosperms. In addition, numerous idioblasts containing phenolic compounds, alkaloids, and lipophilic substances, together with the presence of prismatic crystals, contribute to chemical and structural defense. Accessory buds were observed at all nodes, expanding the bud bank and reinforcing resprouting potential. The combination of mechanical, chemical, and structural traits indicates that D. furfuracea invests in a complex protective strategy for its aboveground buds, corroborating recent evidence of the functional importance of aerial buds in fire-prone ecosystems and extending this perspective to Annonaceae species. Our findings highlight the ecological relevance of aerial bud defenses and expand current frameworks for understanding plant persistence strategies in the Cerrado.