Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title><jats:sec> <jats:title>Aims</jats:title> <jats:p>Root hairs are one root trait among many which enables plants to adapt to environmental conditions. How different traits are coordinated and whether some are mutually exclusive is currently poorly understood. Comparing a root hair defective mutant with its corresponding wild-type, we explored if and how the mutant exhibited root growth adaptation strategies and how dependent this was on substrate.</jats:p> </jats:sec><jats:sec> <jats:title>Methods</jats:title> <jats:p><jats:italic>Zea mays</jats:italic> root hair defective mutant (<jats:italic>rth3</jats:italic>) and the corresponding wild-type siblings were grown under well-watered conditions on two substrates with contrasting texture and hence nutrient mobility. Root system architecture was investigated over time using repeated X-ray computed tomography.</jats:p> </jats:sec><jats:sec> <jats:title>Results</jats:title> <jats:p>There was no plastic adaptation of root system architecture to the lack of root hairs, which resulted in lower uptake of nutrients especially in the substrate with high sorption capacity. The function of the root hairs for anchoring did not result in different root length density profiles between genotypes. Both maize genotypes showed a marked response to substrate. This was well reflected in the spatiotemporal development of rhizosphere volume fraction but especially in the highly significant response of root diameter to substrate, irrespective of genotype.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusions</jats:title> <jats:p>The most salient root plasticity trait was root diameter in response to substrate. Coping mechanisms for missing root hairs were limited to a shift in root-shoot ratio in loam. Further experiments are required, to elucidate whether observed differences can be explained by mechanical properties beyond mechanical impedance, root or microbiome ethylene production or differences in diffusion processes within the root or the rhizosphere.</jats:p> </jats:sec>

<jats:title>Abstract</jats:title><jats:sec> <jats:title>Purpose</jats:title> <jats:p>Green manuring can increase the plant available fraction of zinc (Zn) in soil, making it a potential approach to increase wheat Zn concentrations and fight human Zn deficiency. We tested whether green manure increases the ability of both the native soil bacteria and inoculated Zn solubilizing bacteria (ZSB) to mobilize Zn.</jats:p> </jats:sec><jats:sec> <jats:title>Methods</jats:title> <jats:p>Wheat was grown in a pot experiment with the following three factors (with or without); (i) clover addition; (ii) soil x-ray irradiation (i.e. elimination of the whole soil biota followed by re-inoculation with the native soil bacteria); and (iii) ZSB inoculation. The incorporation of clover in both the irradiated and the ZSB treatments allowed us to test green manure effects on the mobilization of Zn by indigenous soil bacteria as well as by inoculated strains.</jats:p> </jats:sec><jats:sec> <jats:title>Results</jats:title> <jats:p>Inoculation with ZSB did neither increase soil Zn availability nor wheat Zn uptake. The highest soil Zn availabilities were found when clover was incorporated, particularly in the irradiated soils (containing only soil bacteria). This was partly associated with the stimulation of bacterial activity during the decomposition of the incorporated green manure.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusion</jats:title> <jats:p>The results support that the activity of soil bacteria is intimately involved in the mobilization of Zn following the incorporation of green manure.</jats:p> </jats:sec>

<jats:title>Abstract</jats:title><jats:sec> <jats:title>Aims</jats:title> <jats:p>We studied the regeneration dynamics of woodlands and abandoned old fields in a landscape dominated by <jats:italic>Quercus suber</jats:italic> in its lower limits of rainfall and temperature. Two hypotheses were established: (1) regeneration of <jats:italic>Quercus</jats:italic> species is strongly favored by the presence of tree cover; and (2) growth of <jats:italic>Q. suber</jats:italic> is driven by the climatic variables that represent the lower ecological limit of its leading distribution edge.</jats:p> </jats:sec><jats:sec> <jats:title>Methods</jats:title> <jats:p>We selected woodlands and old fields with and without tree remnants (<jats:italic>n</jats:italic> = 3 per type), and analyzed stand structure, soil parameters and tree growth.</jats:p> </jats:sec><jats:sec> <jats:title>Results</jats:title> <jats:p>Succession was arrested in old fields without tree remnants. By contrast, remnant trees were accelerators of forest recovery in old fields. Tree cover played a fundamental role in <jats:italic>Quercus</jats:italic> recruitment throughout seed dispersal and facilitation that mitigate the effects of summer drought on seedlings. Also, tree cover improved soil parameters (e.g., organic matter) that are important factors for understanding differences in regeneration. Winter/spring precipitation exerted a positive effect on tree growth, as well as temperatures during winter/spring and September.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusions</jats:title> <jats:p>Regeneration dynamics are modeled by the density of tree cover in the cold and dry edge of the distribution area of <jats:italic>Q. suber</jats:italic> where <jats:italic>Q. ilex</jats:italic> is increasing in abundance. Although temperature has a positive effect on the tree growth of <jats:italic>Q. suber</jats:italic>, when demographic processes are considered, decreases in water availability likely play a critical role in <jats:italic>Q. ilex</jats:italic> recruitment. This in turn changes dominance hierarchies, especially in abandoned areas with little or no tree cover.</jats:p> </jats:sec>

<jats:title>Abstract</jats:title><jats:sec> <jats:title>Aim</jats:title> <jats:p>Intercropping often leads to improved productivity of individual species compared to monocultures. We have practically little knowledge of facilitation effects in different intercropping systems and their importance in creating soil legacies that can indirectly affect the succeeding crop in a crop rotation through plant-soil feedback (PSF) effects.</jats:p> </jats:sec><jats:sec> <jats:title>Methods</jats:title> <jats:p>To test this, we used a two-phased field experiment where we combined intercropping and crop rotation. During intercropping, we grew maize, faba bean, and lupine in monocultures or two-species crop combinations. The following season, we grew winter barley on the soil previously used for intercropping to test PSF effects under field conditions.</jats:p> </jats:sec><jats:sec> <jats:title>Results</jats:title> <jats:p>We found evidence for facilitative effects on aboveground biomass production that were species-specific with faba bean and maize biomass benefitting when intercropped compared to their expected biomasses in monocultures. Lupine, in contrast, performed best in monocultures. After the intercropping phase, total soil mineral nitrogen was higher in legume monocultures creating soil legacies but this did not affect soil microbial parameters and barley biomass production in the follow-up rotation phase.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusions</jats:title> <jats:p>We found support for species-specific positive and negative interactions in intercropping. Our results also demonstrated that soil legacies play no significant role under moderately high nutrient environments.</jats:p> </jats:sec>