Although drought is an increasing problem in agriculture, the contribution of the root-associated bacterial microbiome to plant adaptation to water stress is poorly studied. We investigated if the culturable bacterial microbiome associated with five grapevine rootstocks and the grapevine cultivar Barbera may enhance plant growth under drought stress. Eight isolates, over 510 strains, were tested in vivo for their capacity to support grapevine growth under water stress. The selected strains exhibited a vast array of plant growth promoting (PGP) traits, and confocal microscopy observation of gfp-labelled Acinetobacter and Pseudomonas isolates showed their ability to adhere and colonize both the Arabidopsis and grapevine rhizoplane. Tests on pepper plants fertilized with the selected strains, under both optimal irrigation and drought conditions, showed that PGP activity was a stress-dependent and not a per se feature of the strains. The isolates were capable of increasing shoot and leaf biomass, shoot length, and photosynthetic activity of drought-challenged grapevines, with an enhanced effect in drought-sensitive rootstock. Three isolates were further assayed for PGP capacity under outdoor conditions, exhibiting the ability to increase grapevine root biomass. Overall, the results indicate that PGP bacteria contribute to improve plant adaptation to drought through a water stress-induced promotion ability.
Loess in Northern Italy has been usually considered deposited during the MIS 4-2 period, which corresponds to the last Pleistocene glacial cycle. In particular, no absolute dating evidenced loess depositions older than ca. 89 ka. We investigated two strongly rubified soil profiles in the southern margin of the Alpine range in Lombardy to prove their aeolian origin and age of formation. MethodsWe analysed the granulometry of all genetic horizons of these strongly rubified soils and a total of 8 samples were collected for luminescence dating purpose. ResultsMost of the analysed soil horizons were dominated by silt and were characterized by the s-shaped granulometric curve, typical of loess materials. A particularly high clay content evidenced a strong weathering degree. A deep horizon was particularly clay-rich and it was interpreted as a typical Terra-Rossa horizon. Luminescence dates increased with depth, reaching 122 ka for the deepest loess layer and 453 ka (minimum age) for the Terra-Rossa horizon. ConclusionsThe deepest observed loess layer represents the oldest quantitatively dated aeolian deposition in Northern Italy up to now.
<p>On an unglaciated karst landscape in the Lombard Pre-Alps (Salmezza, Bergamo, Italy), an extremely high pedodiversity occurs across a few hectares on Norian dolostone. The rock is locally enriched in well crystallized sand-grained quartz. The climate of the area is suboceanic, with >1500 mm of annual rainfall, and an average temperature around 6-8&#176;C. Rendzic Leptosols and Phaeozems are developed on the steepest slopes, Podzols, Cambisols and Luvisols on flatter areas, while Rhodic Luvisols/Alisols (Terra-Rossa soils) are found in doline cracks and crevices. The sand-grained quartz content of the parent rock seems to be the main soil differentiating factor: where it is abundant (ca. 10-20% in volume), it is responsible for the genesis of Podzols.</p><p>We sampled and analyzed 9 soil profiles from the Salmezza area, thus characterizing all pedogenic processes active in the area. In particular, we analyzed standard soil chemical properties (pH, organic carbon, base status and Cation Exchange Capacity, dithionite and oxalate-extractable Fe and Al); we performed a total elemental analysis on most samples and on substrate samples, in order to calculate mass balance and element loss and enrichment; we observed thin sections and performed XRD analysis in powder samples and on the clay fraction of most pedogenic horizons as well.</p><p>The parent material is a rather pure dolostone, composed of dolomite, locally enriched in quartz. No other minerals have been observed. Very little amounts of Fe, Al and other elements are thus included in the parent rock (almost completely composed of Ca, Mg and Si), often very close to the analytical detection limit. Ca and Mg were almost completely lost during most soil forming processes in this temperate humid climate, while the enrichment in Si, Fe, Al varies broadly amidst the different soils, thanks to different pedogenic processes. Fe and Al, in particular, were up to 120 times more concentrated in Bt and Bhs horizons than in the parent rock. The ratios between stable elements in rocks and soils verifies important inputs of aeolian materials. The values are, however, different also amidst different soils, so an univocal origin of aeolian materials cannot be hypothesized. The mineralogy of the clay fraction is also strongly modified by pedogenesis, so that each soil type is characterized by a different mineralogical assemblage, making it difficult to detect signatures of specific aeolian origins as well.</p>
<p>The spatial variability of hydrocarbon content and the physical and chemical properties of the soil were assessed by combining traditional soil sampling and proximal geophysical survey with the aim of planning a pilot phytoremediation experiment in an agricultural area west of Milan (Lombardy, Italy).</p><p>The area, an irrigated arable land of about 1 ha, was affected by a refined oil spillage from an underground pipeline in 2015. Contamination surveys were carried out with a continuous core drilling technique using an hydraulic probe (131 cm diameter core). Heavy (C>12) and light (C<12) alkanes and aromatic compounds (benzene, ethylbenzene, styrene, toluene and xilenes) were measured up to three meters depth. Results showed a predominance of heavy hydrocarbons (C>12) with respect to light hydrocarbons (C<12) and aromatic compounds. A map of heavy hydrocarbons soil concentration was obtained using geostatistical techniques.</p><p>In 2019 it was decided to carry out a phytoremediation intervention to reclaim the first meter of contaminated soil where heavy hydrocarbons content ranges from 500 to 5000 mg/kg. The first step of the intervention consists in cultivating a wide variety of vegetal species in experimental plots with different pollution to verify their effectiveness for remediation in the specific environmental condition of that area. For the reclamation of deeper more contaminated layers, enhanced bioremediation have been planned to be used.</p><p>Soil properties, which are crucial for planning phytoremediation activities, were investigated using traditional methods and geophysical surveys. Traditional soil survey was performed describing the 23 drilling cores used to monitor pollutants and opening five profiles; the samples were collected from genetic soil horizons and analysed for organic carbon and the main nutrient (nitrogen, phosphorus and potassium) content, total carbonates, texture and pH in water. The distribution of Eutric Luvisols and Cambisols, developed mainly on sandy or sandy skeletal substrate, was represented in a soil map. A proximal geophysical survey was carried out using an electromagnetic induction (EMI) sensor (GSSI Profiler EMP-400) by acquiring multiple frequencies; soil detailed conductivity maps for each frequency (15000, 9000 and 2000 kHz) were obtained. No significant relationships were found between soil electrical conductivity and hydrocarbon concentration, whereas there are relationships with the main soil characteristics: this allowed detailed maps of soil parameters to be obtained.</p><p>On the base of both the soil spatial characterization (traditional soil map and detailed soil property maps with geophysical approach) and the contaminant distribution (hydrocarbon map distribution using geostatistical approach), homogeneous areas were identified in which to set up experimental phytoremediation plots to test the most suitable species for reclamation, chosen among the most widespread crops in the region and considering their suitability for biomass and bio-oil production.</p>
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.