Browsing by Author "Sousa, Nadine"
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- Benefits of ectomycorrhizal inoculation of tilia tomentosa seedlings on plant growth and vigor depends on substrate pHPublication . Serafim, Cindy; Ramos, Miguel A.; Yilmaz, Tugce; Sousa, Nadine; Castro, Paula M. L.
- Detection and quantification by real-time PCR of ectomycorrhizal fungi in inoculum formulations for urban trees applicationPublication . Serafim, Cindy; Ramos, Miguel; Castro, Paula Lima; Sousa, NadineBackground: Urban trees are key elements in mitigating the common environmental problems in urban areas, through provisioning crucial ecosystem services such as air quality improvement, decrease of water runoff and microclimate mitigation. Because of their well-known host tree benefits, Ectomycorrhizal Fungi (EcM) may play an important role in urban tree management, improving tree vigor, and thus the extent and resilience of ecosystem services delivered by urban trees under stress. Therefore it is important to develop dedicated EcM-inocula to improve urban tree health and its associated ecosystem service delivery. To support the study of the effect of inoculum application in urban context it is necessary to establish new biotechnology tools and test their efficacy in laboratory trials. The major aims of this work were (i) to isolate EcM species known to associate with the selected tree species chosen (Tilia tomentosa) and (ii) to develop and test (in situ & ex situ) a specific RT-qPCR assays for detection and quantification of ectomycorrhizal RNA. The latter will allow fast, quantitative monitoring of the selected target species over time, space or different environmental conditions and can be directly applied to RNA samples from in-vitro and field experiments. Method: Two key-criteria were used in the fungi species selection: EcM species that are present on healthy urban trees, but absent on the unhealthy ones; and (ii) EcM species from forest/old park trees that are not found on the unhealthy street trees. Fungi were isolated from Northern Portugal and identified by molecular techniques (DNA extraction, PCR, sequencing). For each fungal species selected, a real-time reverse-transcription quantitative PCR (RT-qPCR) assay was developed based on the ITS sequences available in NCBI and UNITED data base enabling specific monitoring and quantification of viable or active EcM of interest during the experiments that will be conducted. Results & Conclusions: Ten new fungal isolates were successfully isolated, comprising the genera Russula, Pisolithus and Paxillus. The standard curves obtained for mycelial quantification of the chosen EcM species satisfy the requirements for real-time PCR, showing high reaction efficiency. Under the conditions established in the present work, mycelium concentration was detectable to levels adequate for biomass in situ quantification.
- Foliar optical traits indicate that sealed planting conditions negatively affect urban tree healthPublication . Yu, Kang; Geel, Maarten Van; Ceulemans, Tobias; Geerts, Willem; Ramos, Miguel Marcos; Sousa, Nadine; Castro, Paula M. L.; Kastendeuch, Pierre; Najjar, Georges; Ameglio, Thierry; Ngao, Jérôme; Saudreau, Marc; Honnay, Olivier; Somers, BenUrban trees play a key role in mitigating environmental problems in cities, but they often face harsh environmental conditions as they generally grow in sealed soils that have small rooting space and low water availability. In this context, rapid monitoring and assessment of tree health status is critical to maintain urban trees and secure the provisioning of urban ecosystem services. Across three European cities we selected 187 Tilia tomentosa trees growing under following planting conditions: (i) sealed, trees planted in small soil pits or strips surrounded by highly sealed surfaces (concrete, pavement or asphalt); and (ii) unsealed, trees planted in roomy soil surfaces (e.g. parks). We measured leaf reflectance and fluorescence and derived a set of optical traits from the measurements. We examined whether these non-destructively measured optical traits differ between planting conditions and whether they correlate with leaf functional traits, e.g. specific leaf area (SLA), leaf water content (LWC) and leaf water per area (LWA). Compared to the unsealed trees, sealed trees showed decreased SLA and LWC while increased LWA. Leaf optical traits differed between the unsealed and sealed trees. Highly sealed soilsaccelerated leaf senescence of the sealed trees compared to the unsealed trees, embodied in the temporal trend of optical traits. Sealed planting conditions negatively affect urban tree health status and phenology. These negative effects can be estimated by leaf optical traits, emonstrating the great potential of optical traits in assessing tree health status. Our findings provide insights into facilitating urban green management using optical traits and remote sensing data.
- Non-invasive monitoring of stress response of urban trees inoculated with EcMPublication . Serafim, Cindy; Ramos, Miguel; Yilmaz, Tugce; Sousa, Nadine; Castro, Paula M. L.
- Non-invasive monitoring of stress response of urban trees inoculated with EcMPublication . Serafim, Cindy; Ramos, Miguel A.; Yilmaz, Tugce; Sousa, Nadine; Castro, Paula M. L.
- Performance of Quercus suber L. at nursery stage - application of two bio-inoculants under two distinct environmentsPublication . Araújo, Giovânia C.; Sousa, Nadine; Ramos, Miguel; Vega, Alberto L.; Castro, Paula M. L.Key message - Despite the fact that the technique of application of bioinoculants improved the quality of Quercus suber L. seedlings produced in nurseries, these benefits are dependent on the ecological conditions of the site and the composition of the applied inoculum, which interferes with the profile of the local fungal community. Context - Quercus suber L. plays a key ecological and socio-economical role in the Iberian Peninsula. Symbiotic ectomycorrhizal fungi-ECM are crucial partners of several tree species, and assessing the efficacy of bioinoculants at nursery stage helps devising tools to increase plant resilience. Aims - The aim of this study was to compare the effects of two inocula formulations of mixed ECM fungi and bacteria on the quality of seedlings produced in two forest nurseries, differing in environmental conditions and forest embedment. Methods - Quercus suber L. seedlings were inoculated with a commercial product containing Pisolithus tinctorius (Pers) Coker Couch - Scleroderma sp., and six bacterial species and with a non-commercial fungal and bacterial dual inoculum (Suillus granulatus (L.) Roussel + Mesorhizobium sp.). Biometric and nutritional parameters and morphological quality indexes were determined on seedlings. The ECMcommunity was assessed by denaturing gradient gel electrophoresis and cloning-sequencing. Results - In both nurseries, the seedling quality index in inoculated was up to 2-fold higher than in non-inoculated seedlings. Plant biomass differed significantly among nurseries. The inoculum influenced the profile of the fungal community. S. granulatus and P. tinctorius persisted for 6 months in the inoculated seedlings. Conclusion- The nursery ecosystem influenced plant growth. Inoculation treatments increased plant performance; however, the dual inoculum resulted in more consistent improvements of Q. suber at nursery stage, highlighting the importance of inocula selection.
- Selection and acclimatization of strains of edible mycorrhizal fungi for improved field persistencePublication . Ramos, Miguel; Sousa, Nadine; Castro, Paula M. L.
- Vegetation reflectance spectroscopy for biomonitoring of heavy metal pollution in urban soilsPublication . Yu, Kang; Geel, Maarten Van; Ceulemans, Tobias; Geerts, Willem; Ramos, Miguel Marcos; Sousa, Nadine; Castro, Paula M. L.; Somers, BenHeavy metals in urban soils may impose a threat to public health and may negatively affect urban tree viability. Vegetation spectroscopy techniques applied to bio-indicators bring new opportunities to characterize heavy metal contamination, without being constrained by laborious soil sampling and lab-based sample processing. Here we used Tilia tomentosa trees, sampled across three European cities, as bio-indicators i) to investigate the impacts of elevated concentrations of cadmium (Cd) and lead (Pb) on leaf mass per area (LMA), total chlorophyll content (Chl), chlorophyll a to b ratio (Chla:Chlb) and the maximal PSII photochemical efficiency (Fv/Fm); and ii) to evaluate the feasibility of detecting Cd and Pb contamination using leaf reflectance spectra. For the latter, we used a partial-least-squares discriminant analysis (PLS-DA) to train spectral-based models for the classification of Cd and/or Pb contamination. We show that elevated soil Pb concentrations induced a significant decrease in the LMA and Chla:Chlb, with no decrease in Chl. We did not observe pronounced reductions of Fv/Fm due to Cd and Pb contamination. Elevated Cd and Pb concentrations induced contrasting spectral changes in the red-edge (690–740 nm) region, which might be associated with the proportional changes in leaf pigments. PLS-DA models allowed for the classifications of Cd and Pb contamination, with a classification accuracy of 86% (Kappa = 0.48) and 83% (Kappa = 0.66), respectively. PLS-DA models also allowed for the detection of a collective elevation of soil Cd and Pb, with an accuracy of 66% (Kappa = 0.49). This study demonstrates the potential of using reflectance spectroscopy for biomonitoring of heavy metal contamination in urban soils.