Structural and chemical responses of Noticastrum hatschbachii Zardini (Asteraceae: Astereae) to coastal environments

Noticastrum hatschbachii is an endemic species of coastal environments in southern Brazil, occurring in the Parque Natural Municipal das Dunas da Lagoa da Conceição (Florianópolis, Santa Catarina). It is currently listed in the Brazilian red lists due to strong anthropogenic pressure on coastal ecosystems. The performance of species in these environments may be influenced by morphoanatomical and physiological mechanisms shaped by both biotic and abiotic factors. This study aimed to investigate anatomical and chemical features of N. hatschbachii using UHPLC-MS analyses. The leaves exhibited bundle sheath extensions and paraveinal parenchyma, whereas the stem displayed a conspicuous parenchymatic structure typically associated with water conservation. The roots exhibited variations in cambial activity characterized by abundant radial parenchyma and additional cambium, which is consistent with resistance and flexibility in sandy soils exposed to constant winds. Glandular trichomes occurred on leaves and stems, and secretory canals were found in leaves, stems, and, more rarely, in roots. These structures contained phenolic compounds, terpenes, pectic substances, and lipophilic compounds, which likely function as defense mechanisms against herbivory. Hydathodes were also observed on leaves, suggesting a potential role in excreting ions through guttation, consistent with the saline coastal environment. Chemical analyses revealed several metabolites; especially phenolic compounds derived from hydroxycinnamic acid and flavonoids. These results expand knowledge of the morphoanatomy and chemical composition of N. hatschbachii, providing a basis for species characterization and future studies in the genus. They also support the importance of conserving coastal biodiversity and highlight the need for actions to preserve endemic species.