DOI: 10.5061/dryad.280gb5n1t
title: Data from: Plant responses to light competition: Does evolutionary history matter?

description: Plants can respond to light-competition cues with sets of plastic
 responses that provide either shade avoidance or tolerance, and were
 suggested to match these strategies to the competition scenarios they
 experience. However, little is known about the effect of plants'
 evolutionary history on their ability to shift between these strategies.
 To fill this knowledge gap, we performed a common-garden experiment that
 examined shade avoidance and tolerance responses of the winter annual
 plant Hymenocarpos circinnatus to a variety of simulated light-competition
 scenarios, including different heights and densities of surrounding
 vegetation. These responses were compared across plants originating from
 six populations along a climatic gradient; from a semi-arid region, where
 light competition is relatively weak and homogenous, to a
 mesic-Mediterranean region, where light competition is stronger and more
 heterogenous. In most of the studied traits, including those related to
 shade avoidance, such as vertical elongation, or to shade tolerance, such
 as photosynthetic efficiency, we found no evidence for differences among
 H. circinnatus populations in the extent of their shade avoidance or
 tolerance responses to light competition. Interestingly, however,
 regardless of their evolutionary history, H. circinnatus were more
 responsive to cues of neighbor density rather than height in both shade
 tolerance and avoidance traits. Moreover, we found differences among
 populations in mean values of some of the studied traits across
 treatments, particularly in the onset of flowering and internode length,
 which are related to aridity adaptations to the shorter and unpredictable
 growth season in the more arid sites. The little divergence we found in
 light-competition responses across populations along the climatic gradient
 might reflect low costs of plasticity in these traits in H.
 circinnatus. Moreover, our results indicate that procumbent plants such as
 H. circinnatus might respond more to lateral competition cues that
 indicate neighbor density than to vertical cues that indicate neighbor
 height, thus highlighting the need to incorporate the two types of cues
 when studying plastic responses of plants to competition.
description: # Plant responses to light competition: Does evolutionary history matter?
 Dataset DOI: [10.5061/dryad.280gb5n1t](10.5061/dryad.280gb5n1t) ##
 Description of the data and file structure We performed a common-garden
 experiment where we measured varying shade avoidance and tolerance
 responses of the winter annual plant *Hymenocarpos circinnatus*, under
 five light-competition treatments that simulated different heights and
 densities of a surrounding vegetation. These responses were compared
 across plants originating from six populations along a climatic gradient,
 from a semi-arid to a mesic-Mediterranean region. ### Files and variables
 #### File: First et al. Data.xlsx **Description:**  ##### Variables *
 Plant ID: ID number of the pot and individual plant. * Block: a random
 factor with the 10 experimental blocks, according to which the plants were
 arranged on the experimental benches, each containing the five treatment
 combinations and the six populations. * Population: a random factor with
 the six populations of origin. * Annual precipitation: a covariate that
 provides mean annual rainfall (mm) * Neighbor height: a fixed factor with
 three treatments (control, short, or tall). * Neighbor density: a fixed
 factor with three treatments (control, sparse, or dense). *
 height:diameter ratio: a dependent variable, measured as the ratio between
 the height and diameter of *H. circinnatus.* * Leaf angle: a dependent
 variable, visually estimated for the leaves of *H. circinnatus* and
 categorized as either 0, 45 or 90° relative to the horizontal plane (°). *
 Branching intensity: a dependent variable, measured as as the number of
 active meristems (branches) relative to total meristem number per stem
 (branched nodes plus un-branched nodes) of *H. circinnatus.* * Stem-base
 diameter: a dependent variable, measured as mean diameter of the two main
 stems of *H. circinnatus *(cm). * Internode length: a dependent variable,
 measured as the ratio of stem length to the number of internodes of *H.
 circinnatus *(cm). * SLA (specific leaf area): a dependent variable,
 measured as the ratio of leaf surface area to leaf dry mass of *H.
 circinnatus *(cm^2 / g). * Leaf area: a dependent variable, measured as
 the leaf surface area of *H. circinnatus *(cm^2). * Amax (maximal
 photosynthetic rate): a dependent variable, estimated by fitting the
 carbon assimilation measurements for each *H. circinnatus* plant with
 light response curves using the Mitscherlich function (μmol / (s * m^2)).
 * Aqe (apparent quantum efficiency): a dependent variable, estimated by
 fitting the carbon assimilation measurements for each *H.
 circinnatus* plant with light response curves using the Mitscherlich
 function. * LCP (light compensation point): a dependent variable,
 estimated by fitting the carbon assimilation measurements for each *H.
 circinnatus* plant with light response curves using the Mitscherlich
 function (μmol / (s * m^2)). * Shoot mass: a dependent variable, measured
 as shoot dry mass of *H. circinnatus* (g). * inflorescence number: a
 dependent variable, measured as the number of *H. circinnatus* 
 inflorescences at the time of harvest. Blank cells represent unavailable
 data. ## Code/software Microsoft Excel / Google Sheets ## Access
 information Mean annual rainfall (1990-2020) provided by the Israel
 Meteorological Service Archives.