DOI: 10.71615/bexis.31834
title: Number of seedlings germinated as obtained in a common garden experiment under ambient light and temperature conditions for 219 grassland species common in the experimental grassland plots of the Biodiversity Exploratories

description: During the last two decades, the research on plant functional traits has advanced rapidly. However, so far, research has focused on traits of adult plants, while research on seedling traits is scarce. Seedling traits, however, could play an important role during plant establishment from seeds and they are essential to understand the full plant life cycle. <br>We studied the seedling traits: the number of seeds that germinated, the number of weeks until 50% of seeds had germinated (= T50), the date when the first seeds had germinated, and the number of weeks until the first seed had germinated. For this, we examined 219 temperate grassland species which were sown as single species in a microcosm experiment. The experiment was conducted in an open greenhouse with ambient light and temperature conditions (UFZ Field Station Bad Lauchstädt, Saxony-Anhalt, Germany) between November 2020 and July 2021. We obtained data for 213 species, which germinated successfully.<br>The microcosm experiment was part of the project SeedDiv within the framework of the DFG-funded joint project Biodiversity Exploratories (https://www.biodiversity-exploratories.de).
description: Study design: Species were selected from the species inventories of the grassland experimental plots of the Biodiversity Exploratories (EPs) including all species, that occurred between 2008 and 2019 on more than three plots irrespective of their cover abundances or on fewer plots with a cover-abundance &gt;1% resulting in 233 species. When possible, seeds were bought commercially from local suppliers preferentially from provenances in or close to the Exploratory regions. Seeds of some species, where it was not possible to buy seeds, we collected ourselves in the summer of 2020. (For seed sources see data set ID 31927). Seeds were stored at room temperature (at approx. 22°C) until they were prepared for the experiment.<br><br>The microcosm experiment was carried out in a greenhouse with open windows and a glass roof that closes during rain at the field station of the Helmholtz Centre for Environmental Research, UFZ in Bad Lauchstädt (51.3923°, 11.8759°, 117 m a.s.l.). The experiment was sown between the 16th and 24th of November 2020. Sowing in late autumn guaranteed cold stratification and/or short days, which are necessary for several species to induce germination. All species were separately sown with 50 seeds in pots of 11 x 11 cm size (12 cm depth) with five replicates per species resulting in 1054 microcosms. The pots were arranged in five blocks each with one replicate per species. <br>Pots were filled with commercial potting substrate (Fruhstorfer Erde®, Type P70, Industrie-Erdenwerke Archut GmbH, Lauterbach, Germany) mixed with 25 vol% mineral sand. The mixture contained 66.35 mg kg⁻¹ plant-available phosphorus, and 283.80 mg kg⁻¹ plant-available potassium (both determined with the CAL method). Soil carbon concentration was 65.2 mg g-1, and total soil nitrogen concentration was 1.3 mg g-1. The pH (measured in a CaCl2 solution) was 7.0. Seeds were gently pressed on the soil surface and covered with a thin layer of mineral sand to avoid loss through wind. Pots and trays were watered regularly as needed. | Sampling design: Seedlings were counted weekly from the beginning of December 2020 until the end of July 2021. | Sample preparation: T50, i.e. the time (week) when 50% of the seedlings, which emerged until the end of the experiment had germinated, and the time (week), when the first seedling had emerged (Week1stgerm) were calculated in R with the germinationmetrics package (Aravind et al. 2023). | Sample analysis: The final number of seedlings that emerged per pot (FinalNo) and the date of the first seedling (Date1stgerm) were extracted from the weekly counting. | Equipment: R package germinationmetrics (Aravind et al. 2023) | Data preparation: The data set does contain the values of all measurements after checking the raw data for plausibility. | Data references: Aravind, J.; Vimala Devi, S.; Radhamani, J.; Jacob, S. R.; Kalyani Srinivasan (2023): germinationmetrics: Seed Germination Indices and Curve Fitting. Version R package version 0.1.8. Online verfügbar unter https://github.com/aravind-j/germinationmetricshttps://cran.r-project.org/package=germinationmetrics.