Contrasting responses of naturalized alien and native plants to native soil biota and drought: biomass and mycorrhizal colonization data.

This data set contains the raw data of an experimental project in which we examined the interactive effects of drought and presence of a soil community on the competition between native and alien grassland plant species.In our greenhouse pot experiment, we first established pots with either living or sterilized soil collected from a grassland patch near the University of Konstanz. We subsequently established competition treatments by growing ten different alien and native grassland species in absence of competition, in intraspecific competition, or in interspecific competition. For the interspecific competition treatment, we only established the combinations of alien and native plant species. Initial leaf area values were estimated for each plant, by combining initial leaf number and measurements of the width and length of the longest leaf. Soil moisture was maintained at 20% (w/w) until the fifth week of the experiment, when we started a drought treatment of four subsequent weeks, by maintaining soil moisture at 10% (w/w) in half of the pots. Plants in total were grown for 50 days, after which shoots (for all pots) and roots (for plants grown in absence of competition) were harvested, dried and weighed. Based on these data, total biomass and biomass allocation (root weight ratio) were also determined for plants grown in absence of competition. The corresponding data are found in the ‘Biomass’ tab of the file “Alien_Native_Biomass_Mycorrhizal_colonization.xlsx”.As multiple plant species positively responded to the presence of a living soil community, we used root systems of plants grown in absence of competition to examine whether colonization by arbuscular mycorrhizal fungi (AMF) explained differences in plant responses sterilized and living soil. Mycorrhizal presence and absence data, based on microscopical analysis with 100 observations per root system, following root staining using an Ink-vinegar solution, are presented in the ‘Mycorrhizal_colonization’ tab of the file “Alien_Native_Biomass_Mycorrhizal_colonization.xlsx”.

本数据集包含一项实验研究的原始数据，该实验旨在探究干旱胁迫与土壤群落存在与否，对本土与外来草原植物物种间竞争的交互影响。
本研究于温室开展盆栽实验：首先从康斯坦茨大学附近的草原斑块采集土壤，分别制备活体与灭菌土壤基质并装入花盆。随后设置竞争处理，将10种不同的外来与本土草原植物分别种植于无竞争、种内竞争或种间竞争环境中；其中种间竞争处理仅包含外来与本土植物物种的组合。
通过统计初始叶片数量，并测量最长叶片的长宽，估算每株植物的初始叶面积。实验前5周维持土壤含水量为20%（重量比，w/w）；自第5周起启动为期4周的干旱处理，将半数花盆的土壤含水量降至10%（重量比，w/w）。
所有植物均培养50天后收获：对所有花盆的地上部分进行取样，对无竞争组种植的植物采集根系样品，经烘干后称重。基于上述数据，还计算了无竞争组植物的总生物量及根重比（root weight ratio）。相关数据详见文件"Alien_Native_Biomass_Mycorrhizal_colonization.xlsx"的"Biomass"工作表。
鉴于多数植物物种对活体土壤群落呈现正向响应，本研究利用无竞争组种植的植物根系，探究丛枝菌根真菌（arbuscular mycorrhizal fungi, AMF）定殖情况是否可解释植物在灭菌与活体土壤中的响应差异。采用墨水-醋酸溶液对根系染色后，通过镜检对每个根系系统开展100次观测，得到菌根定殖与否的数据，相关结果详见上述Excel文件的"Mycorrhizal_colonization"工作表。