Leaf fluctuating asymmetry is not a reliable indicator of stress

Stress experienced during development in organisms with bilateral structures could result in developmental instability, which is expressed as subtle non-directional deviations from perfect symmetry, known as fluctuating asymmetry (FA). As such, FA has been proposed, and extensively used, as a trait indicating stress for many organisms with bilateral structures and many types of stress. However, while this concept may apply to animals, the evidence for plants' main vegetative structures, i.e., leaves, remains equivocal, and a comprehensive synthesis on this topic is still missing.
We designed observational field and controlled greenhouse studies, combining different growth and leaf forms across multiple stress gradients, comprising 21 species and 80 populations. We measured FA as the difference between the left and right area of the leaf, an approach that accommodates diverse leaf forms. We used high-precision, blind, single-person measurements and tested for other forms of symmetry and ..., We designed observational field and controlled greenhouse studies, combining different growth and leaf forms across multiple stress gradients, comprising 21 species and 80 populations. We measured FA as the difference between the left and right area of the leaf, an approach that accommodates diverse leaf forms. We used high-precision, blind, single-person measurements and tested for other forms of symmetry and the effect of leaf size. We further complemented our study with a systematic literature review of FA in plant leaves, compiling 51 studies comprising 72 species, 23 stress types, and 131 unique entries (species × stress type)., , # Leaf fluctuating asymmetry is not a reliable indicator of stress

[https://doi.org/10.5061/dryad.547d7wmgk](https://doi.org/10.5061/dryad.547d7wmgk)

These data are linked to the manuscript Majekova et al. 2024 Functional Ecology. Data correspond to the observational and experimental studies reported in the manuscript. Data for the systematic literature review are saved as Appendix A Table A1 of the manuscript.

## Description of the data and file structure

The dataset contains three files ordered as separate spreadsheets:

(1) \"*Greenhouse experiment*\" \"with columns for:

* \"*Species*\" (Hedypnoides rhagadioloides, Hymenocarpos circinatus)
* \"*Watering\_ treatments*\" (30, 50, 90 ml)
* \"*Locality*\" of origin of species seeds (Mediterranean, Semi-arid)
* \"*Individual*\" per Species x Treatment x Locality
* \"*FA_index*\" - fluctuating asymmetry index used (|log (Right leaf side/ Left leaf side)|

(2) \"*Productivity_Gradient_Germany*\" with columns for:

* \"*Species*\" (perenni...