Evidence of combined flower thermal and drought vulnerabilities portends reproductive failure under hotter‐drought conditions

• Published in: Plant, cell and environment cell and environment, 2024-06, Vol.47 (6), p.1971-1986
• Main Authors: Aun, Marina Alves, Farnese, Fernanda, Loram‐Lourenço, Lucas, Abreu, Igor Manoel Paulo Goulart, Silva, Brenner Ryan Arantes, Freitas, Jober Condé Evangelista, Filho, Valdeir Martins Alves, Silva, Fabiano Guimarães, Franco, Augusto Cesar, Hammond, William M., Cochard, Hervé, Menezes‐Silva, Paulo Eduardo
• Format: Article
• Language: English
• Subjects: Carbon; climate change; Comparative analysis; Construction costs; Drought; Drought resistance; drought tolerance; Environmental Sciences; flower hydraulics; Flowers; Leaves; Organs; Plant cuticle; Plant reproduction; Plant reproductive structures; Plants (botany); Reproductive failure; Safety margins; Storage capacity; Structure-function relationships; thermal vulnerability; Turgor; Water storage
• ISSN: 0140-7791; 1365-3040
• DOI: 10.1111/pce.14857

Despite the abundant evidence of impairments to plant performance and survival under hotter‐drought conditions, little is known about the vulnerability of reproductive organs to climate extremes. Here, by conducting a comparative analysis between flowers and leaves, we investigated how variations in key morphophysiological traits related to carbon and water economics can explain the differential vulnerabilities to heat and drought among these functionally diverse organs. Due to their lower construction costs, despite having a higher water storage capacity, flowers were more prone to turgor loss (higher turgor loss point; ΨTLP) than leaves, thus evidencing a trade‐off between carbon investment and drought tolerance in reproductive organs. Importantly, the higher ΨTLP of flowers also resulted in narrow turgor safety margins (TSM). Moreover, compared to leaves, the cuticle of flowers had an overall higher thermal vulnerability, which also resulted in low leakage safety margins (LSM). As a result, the combination of low TSMs and LSMs may have negative impacts on reproduction success since they strongly influenced the time to turgor loss under simulated hotter‐drought conditions. Overall, our results improve the knowledge of unexplored aspects of flower structure and function and highlight likely threats to successful plant reproduction in a warmer and drier world. Summary statement By conducting a comparative morphophysiological analysis between flowers and leaves, we showed that, due to their lower construction costs, flowers were more vulnerable to hotter‐drought events than leaves, thus evidencing possible threats to successful plant reproduction in a warmer and drier world