Codes and datasets for "Increased microbial respiration induced by root exudates does not persist after repeated droughts".

This figshare item offers codes and dataset of figures and tables from paper with title "Increased microbial respiration induced by root exudates does not persist after repeated droughts".The abstract of this paper is:Root exudates play an important role in ecosystem carbon (C) cycling. Drought has been shown to alter the quality and quantity of root exudation, increasing microbial respiration and potentially priming the decomposition of soil organic matter (SOM). However, it is not clear whether and how these responses persist or change after repeated drought. Here, we tested how repeated drought affects root exudation of different plant species, and what the implications are for the microbial respiration triggered by these root exudates. We hypothesised that repetitive drought reduces root exudation and the respiration triggered by these root exudates more in forbs and legumes than in grasses. We exposed three common temperate grassland plant species that represent three functional groups, the grass Lolium perenne (L. perenne), the forb Ranunculus acris (R. acris) and the legume Trifolium pratense (T. pratense) to four treatments, namely well-watered (Control), and plants that experienced drought once (Drought 1), twice (Drought 2) and three-times (Drought 3). We then collected their root exudates and analysed the soil microbial respiration they triggered. Our results showed that three repeated droughts reduced total root exudation released by R. acris and T. pratense but did not change specific root exudation rates. The total amounts of root exudate-induced respiration were also reduced in R. acris and T. pratense after repeated droughts, but specific root exudate-induced respiration rates were not affected. R. acris and T. pratense reduced total root exudation after one and two drought and maintained this level after these events. We also observed a decreasing root carbon/nitrogen (C/N) ratio of R. acris with increasing number of droughts, potentially leading to decreased root exudation and failure of R. acris’s ability to resist drought. L. perenne showed an insensitive response to drought events likely because of its resilience to repeated droughts. Our findings suggest that plant investment in root exudation and the microbial activity they trigger may not persist after repeated drought events.