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

Abstract

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.

Potential of reproductive traits in functional ecology: A quantitative comparison of variability in floral, fruit, and leaf traits

“…Even fewer studies discuss flower physiology, anatomy, and morphology. Some of the questions still needing answers include potential threats to plant reproduction under changing climate conditions (Aun et al., 2024 ), the constraining role of water availability for flower maintenance (Lambrecht, 2013 ), and the vulnerability of flowers to xylem damage due to drought (Zhang & Brodribb, 2017 ). Major gaps in our knowledge of flowers and fruits may result from the lack of standardized data collection protocols, low species coverage, and unbalanced geographic and phylogenetic representation in data from different regions (E‐Vojtkó et al., 2020 , 2022 ).…”

“…Even fewer studies discuss flower physiology, anatomy, and morphology. Some of the questions still needing answers include potential threats to plant reproduction under changing climate conditions (Aun et al, 2024), the constraining role of water availability for flower maintenance (Lambrecht, 2013), and the vulnerability of flowers to xylem damage due to drought .…”