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

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 (FV/FM) following a combination of temperatures and exposure times, 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 FV/FM 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 tha..., Leaf-level data was collected on plants at the Australian Arid Lands Botanic Garden, South Australia, Australia as per methods in the manuscript. Leaf FVFM data on collected detached leaves in response to thermal tolerance assays. Leaf temperature was collected in situ with thermocouples inserted into the leaf epidermis and modeling of leaf and reported air temperatures from the Australian Bureau of Meteorology. See the article for more details., , # Beyond a single temperature threshold: applying a cumulative thermal stress framework to plant heat tolerance

*R Script and data for:*

*Cook et al. Beyond a single temperature threshold: applying a cumulative thermal stress framework to plant heat tolerance. Ecology Letters, 2024.*

Contains 14 files:

(**1) Analyses** - R scripts to replicate analyses and figures in the manuscript and supplementary material (4 files total):

* TDT plants_final.R
* Thermal landscapes functions.R
* Fig 1.R
* Neuner_Buchner.R

**(2) Datasets** (7 files total):

* *Cook_Cleandata_R_TD_MmonEsoc2023_FINAL.csv*
For thermal tolerance and temperature duration analysis
Columns:
* ID - consecutive row numbers
* Trial - Trial 1, 2 or 3
* Date tested - Date leaves were tested
* Species - M.mon, *Myoporum montanum*; E.soc, *Eucalytpus socialis*
* Duration - (min) temperature stress duration; 5, 10, 15 or 30 min
* Temp - (°C), temperature of stress; 28, 48, 50...