Beyond a single temperature threshold: Applying a cumulative thermal stress framework to plant heat tolerance.

Abstract

Most plant thermal tolerance studies focus on single critical thresholds, which limit the capacity to generalise across studies and predict heat stress under natural conditions. In animals and microbes, thermal tolerance landscapes describe the more realistic, cumulative effects of temperature. We tested this in plants by measuring the decline in leaf photosynthetic efficiency (F V /F M ) following a combination of temperatures and exposure times and then modelled these physiological indices alongside recorded environmental temperatures. We demonstrate that a general relationship between stressful temperatures and exposure durations can be effectively employed to quantify and compare heat tolerance within and across plant species and over time. Importantly, we show how F V /F M curves translate to plants under natural conditions, suggesting that environmental temperatures often impair photosynthetic function. Our findings provide more robust descriptors of heat tolerance in plants and suggest that heat tolerance in disparate groups of organisms can be studied with a single predictive framework.

Plant phenotyping relevance

植物の熱耐性を、温度と曝露時間の累積効果および葉の光合成効率から定量・比較する予測フレームワークが研究の中心であり、植物生理状態のフェノタイピング手法に該当する。

Code and data availability

The article's Data Availability Statement explicitly deposits the authors' R scripts and datasets (including the FV/FM heat-tolerance measurements and analysis data) at the Dryad Digital Repository with a public DOI, making this a paper-specific, publicly actionable asset.