Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title><jats:sec> <jats:title> Aims</jats:title> <jats:p> Increased subsoil water extraction through breeding of ‘designer’ root system architecture (RSA) may improve crop performance and resilience in the face of climate change (i.e. changing seasonal rainfall patterns). However, in many dryland environments, root systems face both water and nutrient scarcity (e.g. phosphorus (P)), with both resources often heterogeneously distributed in space and time. Under these conditions, interactions among RSA, nutrient distribution and soil water will determine crop performance, but remain poorly understood.</jats:p> </jats:sec><jats:sec> <jats:title>Methods</jats:title> <jats:p>We grew two sorghum (<jats:italic>Sorghum bicolor</jats:italic>) genotypes defined by contrasting RSA (narrow or wide nodal root angle) in prepared soil cores with heterogeneous distributions of P and water along the soil profile. Plant growth and water use, shoot biomass, P uptake and root distribution were quantified in response to the different water × P combinations.</jats:p> </jats:sec><jats:sec> <jats:title>Results</jats:title> <jats:p>Soil P placement and soil water distribution interactively determined plant growth and development in a genotype-dependent manner. The two sorghum genotypes shared common responses to P and water availability though varied for root and shoot traits and their relative responses to combined P and water stress.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusions</jats:title> <jats:p>Plant responses to the different water × P combinations were illustrative of the occurrence of spatio-temporal trade-offs between root architecture and efficient soil resource capture. The results suggest that the relative ability of crop root systems to effectively exploit soil profiles with greater resource availability will not necessarily be important for crop productivity in heterogeneous soil systems. Local environmental constraints should be considered when deploying genotypes with selected root architectural traits.</jats:p> </jats:sec>

<jats:title>Abstract</jats:title><jats:sec> <jats:title>Background and aims</jats:title> <jats:p>A synergistic response of aboveground plant biomass production to combined nitrogen (N) and phosphorus (P) addition has been observed in many ecosystems, but the underlying mechanisms and their relative importance are not well known. We aimed at evaluating several mechanisms that could potentially cause the synergistic growth response, such as changes in plant biomass allocation, increased N and P uptake by plants, and enhanced ecosystem nutrient retention.</jats:p> </jats:sec><jats:sec> <jats:title>Methods</jats:title> <jats:p>We studied five grasslands located in Europe and the USA that are subjected to an element addition experiment composed of four treatments: control (no element addition), N addition, P addition, combined NP addition.</jats:p> </jats:sec><jats:sec> <jats:title>Results</jats:title> <jats:p>Combined NP addition increased the total plant N stocks by 1.47 times compared to the N treatment, while total plant P stocks were 1.62 times higher in NP than in single P addition. Further, higher N uptake by plants in response to combined NP addition was associated with reduced N losses from the soil (evaluated based on soil δ<jats:sup>15</jats:sup>N) compared to N addition alone, indicating a higher ecosystem N retention. In contrast, the synergistic growth response was not associated with significant changes in plant resource allocation.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusions</jats:title> <jats:p>Our results demonstrate that the commonly observed synergistic effect of NP addition on aboveground biomass production in grasslands is caused by enhanced N uptake compared to single N addition, and increased P uptake compared to single P addition, which is associated with a higher N and P retention in the ecosystem.</jats:p> </jats:sec>

<jats:title>Abstract</jats:title><jats:sec> <jats:title>Background</jats:title> <jats:p>Plants condition the biotic composition of their rhizosphere. In turn, this plant legacy on the soil biota may affect the performance of plants recruiting in their vicinity. Unravelling how plant-soil legacies drive plant recruitment is key to understand vegetation dynamics and plant community assembly. Studies on the topic usually focus on the effects of soil microbiota as a whole, while the relative role of different guilds of soil organisms in the plant recruitment processes is not usually dissected.</jats:p> </jats:sec><jats:sec> <jats:title>Aims</jats:title> <jats:p>Here, we used soils of Mediterranean woody plant species to test whether arbuscular mycorrhizal fungi (AMF) and small-size microbiota (&lt; 50 µm) (MB) affect the germination success and growth of eight herbaceous plants.</jats:p> </jats:sec><jats:sec> <jats:title>Results</jats:title> <jats:p>We documented a significant increase in seedling emergence probability when small-sized MB was present and no effect of AMF. In contrast, the aboveground plant biomass decreased with the presence of MB and increased with that of AMF. Interestingly, those plants growing in the absence of MB and in soils from woody plants associated with higher AMF richness developed higher aboveground biomass.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusion</jats:title> <jats:p>This study brings new evidence on how soil microbial communities can determine the performance of their associated herb community, and also, how the effects of different microbial guilds may change across the plant ontogeny. Given these results, the differential effect of soil microbial functional guilds should be considered to better understand plant soil legacies and feedbacks, potentially driving plant recruitment and community assembly.</jats:p> </jats:sec>