Biology subjects

Lozano, Y. M.

Publications and source records attributed to Lozano, Y. M..

4 recordsLinked to original sources

bioRxiv2022

Legacy effect of microplastics on plant-soil feedbacks

Microplastics are a complex contaminant suite that are now understood to affect plants and soil biota and the processes they drive. However, the role of microplastic in plant-soil feedbacks, a key feature in plant-soil interactions, is still unknown. We address this here, using soil from a previous experiment, which has been conditioned with 12 different microplastic types including fibers, films, foams, and fragments. To evaluate the feedback effect, we grew a native and a range-expanding plant species with inocula extracted from each one of these soils. At harvest, plant biomass and root morphological traits were measured. Films gave rise to a positive feedback on shoot mass (higher mass with soil inocula conditioned with microplastics than without), likely via negative effects on harmful soil biota. Foams and fragments also caused positive feedback on shoot mass likely via effects on enzymatic activities and mutualistic soil biota. Fibers led to negative feedback on root mass as they may promote the abundance of soil pathogens. Microplastics also have a legacy effect on root traits: Daucus had thicker roots probably for promoting mycorrhizal associations while Calamagrostis had reduced root diameter probably for diminishing pathogenic infection. Microplastic legacy on plants is species-specific and may affect plant biomass primarily via root traits. Microplastics, as a function of their shape and polymer type, have a feedback effect on plant performance.

ecology↗

bioRxiv2020

Microplastic shape, concentration and polymer type affect soil properties and plant biomass

Microplastics are an increasing concern in terrestrial systems. These particles can be incorporated into the soil in a wide range of shapes and polymers, reflecting the fact that manufacturers produce plastics in a variety of physical and chemical properties matching their intended use.Despite of this, little is known about the effects that the addition into the soil of microplastics of different shapes, polymer type and concentration levels may have on soil properties and plant performance. To fill this gap, we selected four microplastic shapes: fibers, films, foams and fragments; and for each shape we selected three microplastics made of one of the following polymers: polyester, polyamide, polypropylene, polyethylene, polyethylenterephthalat, polyurethane, polystyrene and polycarbonate. In a glasshouse experiment, each microplastic was added to a soil from a dry grassland at a concentration of 0.1%, 0.2%, 0.3% and 0,4%. A carrot (Daucus carota) plant grew in each pot during four weeks. At harvest, shoot and root mass, soil aggregation and microbial activity were measured. Our results showed that all microplastic shapes increased shoot and root masses. As concentration increased, microfibers increased plant biomass probably as fibers may hold water in the soil for longer. In contrast, microfilms decreased biomass with concentration, likely because they can create channels in the soil that promote water evaporation affecting plant performance. All microplastic shapes decreased soil aggregation, probably since microplastics may introduce fracture points in the aggregates affecting their stability and also due to potential negative effects on soil biota. The latter may also explain the decrease in microbial activity with, for example, polyethylene films. Similar to plant biomass, microfilms decreased soil aggregation with increasing concentration. Our study tested the microplastic shape mediation and dissimilarity hypotheses, highlighting the importance of microplastic shape, polymer type and concentration when studying the effects of microplastics on terrestrial systems.

ecology↗

bioRxiv2020

Effects Of Microplastics And Drought On Ecosystem Functions And Multifunctionality

O_LIMicroplastics in soils have become an important threat for terrestrial systems, which can be exacerbated by drought as microplastics may affect soil water content. Thus, the interaction between these two factors may alter ecosystem functions such as litter decomposition, stability of soil aggregates, as well as functions related to nutrient cycling. Despite this potential interaction, we know relatively little about how microplastics, under different soil water conditions, affect ecosystem functions and ecosystem multifunctionality. C_LIO_LITo address this gap, we carried out a controlled-environment study using grassland plant communities. We applied the two factors microplastic fibers (absent, present) and soil water conditions (well-watered, drought), in all possible combinations in a factorial experiment. At harvest, we measured multiple ecosystem functions linked to nutrient cycling, litter decomposition, and soil aggregation and as terrestrial systems provide these functions simultaneously, we also assessed ecosystem multifunctionality. C_LIO_LIOur results showed that the interaction between microplastic fibers and drought affected ecosystem functions and multifunctionality. Overall, drought had negatively affected nutrient cycling by decreasing potential enzymatic activities and increasing nutrient leaching, while microplastic fibers had a positive impact on soil aggregation and nutrient retention by diminishing nutrient leaching. Microplastic fibers also impacted enzymatic activities, soil respiration and ecosystem multifunctionality, but importantly, the direction of these effects depended on soil water status (i.e., they decreased under well watered conditions, but tended to increase or had similar effects under drought conditions). Litter decomposition had a contrary pattern. C_LIO_LISynthesis and applications. As soil water content is affected by climate change, our results suggest that areas with sufficiency of water would be negatively affected in their ecosystem functioning as microplastics increase in the soil; however, in areas subjected to drought, microplastics would have a neutral or slightly positive effect on ecosystem functioning. C_LI

ecology↗

bioRxiv2019

Root trait responses to drought depend on plant functional group

O_LIDrought can strongly modify plant diversity and ecosystem processes. As droughts are expected to intensify in the future, it is important to better understand plant responses to drought. We expect that roots traits constitute an overlooked but powerful predictor of plant responses as roots are in direct contact with the soil environment, taking up nutrients and water.\nC_LIO_LIHere, we determine which root traits are sensitive to drought, the magnitude of that response, whether their predictive power and relationships with shoot biomass are affected by drought and whether all these responses depend on plant functional group. To do so, we conducted a glasshouse experiment with 24 plant species grown in pots (10 replicates per species), which represent three different functional groups: grasses, herbs and legumes. All replicates were well watered during the first month and then half of the replicates were kept under drought (30 % water holding capacity (WHC)) with the other half serving as control (kept at 70% WHC). After two months of the treatment, leaf and root traits were measured.\nC_LIO_LILeaf traits had a strong but more uniform response to drought compared to root traits. Root trait response was variable and differed by plant functional group. Most grasses had increased root diameter, specific root surface area (SRSA) while decreased root tissue density (RTD) with drought. Production of thicker roots with a low tissue density could allow grasses to achieve greater nutrient and water acquisition through mycotrophy and would be linked to an increase in the reserve of non-structural carbohydrates needed for osmoregulation. Herbs had decreased SRSA and specific root length (SRL) while increase root carbon allocation. Reduction of root elongation or sacrifice of fine roots would be compensated by an increase in root carbon allocation, which allow herbs to improve water uptake. Legumes did not alter root morphological traits but promote an early flowering in order to scape drought.\nC_LIO_LIOur results identify changes in root morphological traits as mechanisms to likely face drought, a response that is species-specific and differed among functional groups.\nC_LI

ecology↗