DOI: 10.5061/dryad.4qrfj6qgz
title: Data for: Caloric restriction extends lifespan in a clonal plant

description: When subjected to dietary caloric restriction (CR), individual animals
 often outlive well-fed conspecifics. Here, we address whether CR also
 extends lifespan in plants. Whereas caloric intake in animals comes from
 ingestion, in plants it derives from photosynthesis. Thus, factors that
 reduce photosynthesis, such as reduced light intensity, can induce CR. In
 two lab experiments investigating the aquatic macrophyte Lemna minor, we
 tracked hundreds of individuals longitudinally, with light intensity – and
 hence, CR – manipulated using neutral-density filters. In both
 experiments, CR dramatically increased lifespan through a process of
 temporal scaling. Moreover, the magnitude of lifespan extension accorded
 with the assumptions that (a) light intensity positively relates to
 photosynthesis following Michaelis-Menten kinetics, and (b) photosynthesis
 negatively relates to lifespan via a power law. Our results emphasize that
 CR-mediated lifespan extension applies to autotrophs as well as
 heterotrophs, and suggest that variation in light intensity has
 quantitatively predictable effects on plant aging trajectories.
description: # Caloric restriction extends lifespan in a clonal plant
 [https://doi.org/10.5061/dryad.4qrfj6qgz](https://doi.org/10.5061/dryad.4qrfj6qgz) Authors: Chmilar SL, Luzardo AC, Dutt P, Pawluk A, Thwaites VC, and Laird RA. Journal: Ecology Letters Contact: [s.chmilar@uleth.ca](mailto:s.chmilar@uleth.ca); [robert.laird@uleth.ca](mailto:robert.laird@uleth.ca) We investigated whether caloric restriction (CR) results in lifespan extension in plants by examining the effect of light intensity on the lifespan on individual *Lemna minor* (duckweed) fronds. We conducted two related experiments; data from Experiment 1 can be found in data file "CR_daily_surv_and_repro"; data from Experiment 2 can be found in data file "CR2_daily_surv_and_repro". In addition to these main data files, we conducted ancillary experiments to determine the effect of treatment on light intensity, and temperature. These data can be found in data files "CR_PAR" and "CR_temperature", respectively. We also included the effects of light intensity on plant size in our supplementary information file. These data can be found in data file "CR_size_and_shape" for Experiment 1, and data file "CR2_size_and_shape" for Experiment 2. ## Description of the data and file structure Description of column headers in data file "CR_daily_surv_and_repro" (Experiment 1) * id: focal frond ID number * position: randomized location on growth shelves (tray-row-column) * light.treatment: treatment group of light intensity (7 total). Number indicates the denominator of the fraction of light intensity relative to the 'full light' treatment, which had the maximum light intensity. L01 = 1/1 intensity ('full light' treatment); L02 = 1/2 intensity; L04 = 1/4 intensity; L08 = 1/8 intensity; L16 = 1/16 intensity; L32 = 1/32 intensity; L00 = 0 intensity ('no light' treatment) * date.birth: date that focal frond detached from parent (MMM-DD-YYYY) * date.last.repro: date last offspring detached from focal frond (MMM-DD-YYYY) * Status.on.Jan.03.2022: status of remaining fronds at experiment termination on Jan 03, 2022. Fronds were considered 'alive' on this date if (1) they were not previously considered dead [i.e., did not have a 2-week period during which no visible offspring were attached to them], and (2) they produced new offspring in the following 2 weeks, during which they were exposed to 'full light' conditions. Of the 31 fronds that remained on Jan 03, 2022, 19 were found to be alive (0/2 in the L16 treatment, 3/11 in the L32 treatment, and 16/18 in the L00 treatment), and the others determined to be dead, retroactive to their date of last reproduction. * \[all remaining columns in MMM.DD.YYYY format]: Number of daughters that detached from focal frond on date implied by column header Description of column headers in data file "CR2_daily_surv_and_repro" (Experiment 2) * id: focal frond ID number * position: randomized location on growth shelves (tray-row-column) * light.treatment: treatment group of light intensity (2 total). Number indicates the denominator of the fraction of light intensity relative to the 'full light' treatment, which had the maximum light intensity. 1 = 1/1 intensity ('full light' treatment); 4 = 1/4 intensity * exclude: whether fronds were excluded from statistical analyses (due to factors such as frond contamination) * date.birth: date that focal frond detached from parent (MMM-DD-YYYY) * date.last.repro: date last offspring detached from focal frond (MMM-DD-YYYY) * offspring.attached.at.death: Number of offspring remaining attached to focal frond once it was considered dead * \[all remaining columns in MMM.DD.YYYY format]: Number of daughters that detached from focal frond on date implied by column header Description of column headers in data file "CR_PAR" * treatment: treatment group of light intensity (7 total). Number indicates the denominator of the fraction of light intensity relative to the 'full light' treatment, which had the maximum light intensity. L01 = 1/1 intensity ('full light' treatment); L02 = 1/2 intensity; L04 = 1/4 intensity; L08 = 1/8 intensity; L16 = 1/16 intensity; L32 = 1/32 intensity; L00 = 0 intensity ('no light' treatment) * shelf: the shelf on which measurement was taken. S2 = shelf 2; S4 = shelf 4 * frond.ID: the ID of focal frond from Experiment 1 whose light filter was used for measurement * PAR: the photosynthetically active radiation (PAR) measured under the filter (in μmol m^−2 s^−1). Measurments were obtained using a Hobo Micro Station data logger and PAR sensor (Hoskin Scientific, Edmonton, AB, Canada) Description of column headers in data file "CR_temperature" * treatment: treatment group of light intensity (7 total). Number indicates the denominator of the fraction of light intensity relative to the 'full light' treatment, which had the maximum light intensity. L01 = 1/1 intensity ('full light' treatment); L02 = 1/2 intensity; L04 = 1/4 intensity; L08 = 1/8 intensity; L16 = 1/16 intensity; L32 = 1/32 intensity; L00 = 0 intensity ('no light' treatment) * shelf: the shelf on which measurement was taken. S2 = shelf 2; S4 = shelf 4 * temperature: the measured temperature of medium within the experimental set-up after equilibration (in degrees celsius). Measurments were obtained using a ‘lollipop’ thermometer (cat. no. 15079712, Fisher Scientific, Waltham, MA, USA) Description of column headers in data files "CR_size_and_shape" (plants in Experiment 1), and "CR2_size_and_shape" (plants in Experiment 2) * id: focal frond ID number * position: randomized location on growth shelves (tray-row-column) * treatment: treatment group of light intensity (7 total). Number indicates the denominator of the fraction of light intensity relative to the 'full light' treatment, which had the maximum light intensity. L01 = 1/1 intensity ('full light' treatment); L02 = 1/2 intensity; L04 = 1/4 intensity; L08 = 1/8 intensity; L16 = 1/16 intensity; L32 = 1/32 intensity; L00 = 0 intensity ('no light' treatment) * exclude: whether fronds were excluded from statistical analyses (due to factors such as frond damage) * note: a note on why the frond was excluded * CSM: Continuous symmetry measurement * CSM.forced: Continuous symmetry measurement, where the line of bilateral symmetry is forced through the point furthest from the centroid * Area.mm: Frond area (in mm^2) * Perimeter.mm: Frond perimeter (in mm) Note: 'NA' values indicate missing data. This could be due to frond death, contamination with microorganisms, or damage to the frond during surface area measurement. ## Code/Software R software is required to run the script. The code file "Lemna_Caloric_Restriction_Part1_2024_04_25" includes the analysis of Experiment 1, and the ancillary experiments. This includes the packages: emmeans, multcomp, multcompView, and devEMF. The code file "Lemna_Caloric_Restriction_Part2_2024_04_25" includes the analysis of Experiment 2. This includes the package: devEMF.