Barley shoot biomass responds strongly to N:P stoichiometry and intraspecific competition, whereas roots only alter thei
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Barley shoot biomass responds strongly to N:P stoichiometry and intraspecific competition, whereas roots only alter their foraging Amit Kumar & Richard van Duijnen & Benjamin M. Delory & Rüdiger Reichel & Nicolas Brüggemann & Vicky M. Temperton Received: 19 February 2020 / Accepted: 28 June 2020 # The Author(s) 2020
Abstract Aims Root system responses to the limitation of either nitrogen (N) or phosphorus (P) are well documented, but how the early root system responds to (co-) limitation of one (N or P) or both in a stoichiometric framework is not well-known. In addition, how intraspecific competition alters plant responses to N:P stoichiometry is understudied. Therefore, we aimed to investigate the effects of N:P stoichiometry and competition on root system responses and overall plant performance. Methods Plants (Hordeum vulgare L.) were grown in rhizoboxes for 24 days in the presence or absence of competition (three vs. one plant per rhizobox), and fertilized with different combinations of N:P (low N + low P, low N + high P, high N + low P, and high N + high P).
Results Shoot biomass was highest when both N and P were provided in high amounts. In competition, shoot biomass decreased on average by 22%. Total root biomass (per plant) was not affected by N:P stoichiometry and competition but differences were observed in specific root length and root biomass allocation across soil depths. Specific root length depended on the identity of limiting nutrient (N or P) and competition. Plants had higher proportion of root biomass in deeper soil layers under N limitation, while a greater proportion of root biomass was found at the top soil layers under P limitation. Conclusions With low N and P availability during early growth, higher investments in root system development can significantly trade off with aboveground productivity, and strong intraspecific competition can further strengthen such effects.
Responsible Editor: Boris Rewald. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s11104-020-04626-w) contains supplementary material, which is available to authorized users.
Keywords Root system responses . Vertical root distribution . Specific root length . Nutrient stoichiometry . Intraspecific competition
A. Kumar (*) : R. van Duijnen : B. M. Delory : V. M. Temperton (*) Ecosystem Functioning and Services, Institute of Ecology, Faculty of Sustainability, Leuphana University Lüneburg, Universitätsallee 1, 21335 Lüneburg, Germany e-mail: [email protected]
Introduction
e-mail: [email protected] e-mail: [email protected] R. Reichel : N. Brüggemann Forschungszentrum Jülich GmbH, Institute of Bio- and Geosciences, Agrosphere (IBG-3), 52425 Jülich, Germany
Nutrient foraging capacity of roots determines plant performance under both heterogeneous soil nutrient availability and belowground competition with neighbors (Stibbe and Märländer 2002; Soleymani et al. 2011; Bennett et al. 2016; Reiss and Drinkwater 2018). Given that nutrient foraging by roots i
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