Cristian Dal Cortivo | Università degli Studi di Padova (original) (raw)

Papers by Cristian Dal Cortivo

Agronomy, 2021

Late-season N application through foliar spraying is recognized as an efficient agronomic practic... more Late-season N application through foliar spraying is recognized as an efficient agronomic practice for improving grain quality in common wheat, although the major part of N is still supplied by soil fertilization. This study assessed the impact of various N doses entirely applied by repeated foliar sprayings on wheat growth, yield and quality, in comparison with conventional soil fertilization management with a recommended dose of 160 kg N ha􀀀1 as ammonium nitrate (C-M). Doses of 96, 104 and 120 kg N ha􀀀1 as both UAN (urea-ammonium-nitrate) and urea applied by foliar spraying were evaluated in a 2-year field trial in Northern Italy in a silty loam soil with 1.7% organic matter.
Here, it was demonstrated that the canopy greenness was similar in all treatments, with slight grain yield increases by the lowest foliar N dose vs. C-M. The higher N foliar doses mainly improved the grain protein content and both high- and low-molecular-weight glutenin subunits (HMW-GS, LMW-GS), particularly with urea. It is concluded that in our fertile soil, managing N fertilization exclusively through foliar spraying is feasible without compromising grain yield and ameliorating quality at the same time. Improved nutrient use efficiency and beneficial environmental effects are also expected by reducing the nitrogen load on the agricultural fields by 25–40%.

Wood ash as a soil amendment has gained wide spread acceptance in the recent years as a sustainab... more Wood ash as a soil amendment has gained wide spread acceptance in the recent years
as a sustainable alternative to chemical fertilizers, although information regarding the effects
of its application on maize growth and yield in the context of climate change and increasing
drought severity is lacking till date. In the present study, field and pot trials were carried out
at the experimental farm of the University of Padova at Legnaro (NE Italy) in a silty-loam soil
in order to investigate the effects of soil amendment with wood ash (0.1% w/w, incorporated
into the 0.2-m top soil) on the bioavailability of mineral elements and their uptake by maize.
Characteristics analyzed included plant growth, leaf transpiration dynamics, and productivity
in two contrasting hybrids, P1921 (drought sensitive) and D24 (drought tolerant). Wood ash
contained relevant amounts of Ca, K, Mg, P, and S, and hazardous levels of Zn (732 mg kg−1
),
Pb (527 mg kg−1
), and Cu (129 mg kg−1
), although no significant changes in total soil element
concentration, pH, and electrical conductivity were detected in open field. Ash application
led to a general increasing trend of diethylene triamine penta-acetic acid (DTPA)-extractable
of various elements, bringing to higher grain P in D24 hybrid, and Zn and Ni reductions in
P1921 hybrid. Here, the results demonstrated that ash amendment enhanced shoot growth
and the number of leaves, causing a reduction of harvest index, without affecting grain yield
in both hybrids. The most relevant result was a retarded inhibition of leaf transpiration under
artificial progressive water stress, particularly in the drought-tolerant D24 hybrid that could
be sustained by root growth improvements in the field across the whole 0–1.5 m soil profile
in D24, and in the amended top soil in P1921. It is concluded that woody ash can be profitably
exploited in maize fertilization for enhancing shoot and root growth and drought tolerance,
thanks to morphological and physiological improvements, although major benefits are
expected to be achieved in drought tolerant hybrids. Attention should be payed when using
ash derived by metal contaminated wood stocks to avoid any health risk in food uses

Agronomy, 2021

Root characteristics and metal uptake in the maize hybrid Naudi were studied in a pot trial, usin... more Root characteristics and metal uptake in the maize hybrid Naudi were studied in a pot trial, using soil artificially highly polluted with Zn, Cu, Co, Cd, and Pb. The addition of these metals as sulfates decreased the soil pH and increased electrical conductivity. As a result of increased bioavailability in the soil pore water, significantly higher concentrations of metals, particularly Pb, Cu, and Co, were found in the shoot tissues of maize at the 3-4 leaf stage. While the lowest increase was in Cd (0.89 mg kg −1 vs. 0.33 mg kg −1 for controls), Zn reached a critical threshold of 75 mg kg −1 vs. 2.76 mg kg −1. Fresh and dry weights of shoots and roots, as well as root length, were markedly reduced, whereas root diameter, tip density, and the branching index increased considerably. A significant adaptation strategy by maize in the polluted soil was an increased fraction of coarse root length and a decreased fraction of finer roots. We conclude that maize is very sensitive to multiple metal pollution, suggesting its potential use as a test plant to evaluate contaminated soils. As length was the most affected root characteristic, measurement of this parameter could be a way of screening genotypes for tolerance to metal contamination and possibly salinity. There also is future scope for investigating whether K fertilization might mitigate metal phytotoxicity, in view of the negative correlations between the shoot K concentration and concentrations of the supplied metals.

Agronomy, 2020

Tritordeum is a novel hexaploid cereal derived from the cross between a wild Chilean barley speci... more Tritordeum is a novel hexaploid cereal derived from the cross between a wild Chilean barley species (Hordeum chilense Roem. et Schultz) and durum wheat (Triticum turgidum ssp. durum Desf.) that is potentially of great interest for human nutrition. In this study, a commercial and an experimental Tritordeum cultivar were analyzed in comparison with a reference durum wheat under conventional and organic management. We demonstrate that Tritordeum is better adapted to organic farming through an increase in the below-ground rhizosphere community of the Bacteroidetes phylum, which includes many bacteria species known to exert beneficial effects on plants, particularly for root growth. Despite a considerably lower grain yield, Tritordeum had better quality traits than durum wheat, particularly under organic farming vs. conventional management, with respect to total protein contents, high molecular weight glutenin subunits, antioxidant free phenols and nutrients (i.e., calcium, potassium, sulphur, iron, and zinc), depending on the cultivar. We conclude that Tritordeum is a promising cereal in light of its quality traits and adaptability to sustainable crop management practices, such as organic farming, although further improvement in yield potential should be pursued by breeding and by optimising the cultivation method.

Frontiers in Plant Science, 2020

In order to reduce chemical fertilization and improve the sustainability of common wheat (Triticu... more In order to reduce chemical fertilization and improve the sustainability of common wheat (Triticum aestivum L.) cultivation, maintaining at the same time high production and quality standards, this study investigated the effects of three commercial biofertilizers on rhizosphere bacterial biomass, biodiversity and enzymatic activity, and on plant growth and grain yield in a field trial. The wheat seeds were inoculated with the following aiding microrganisms: (i) a bacterial consortium (Azospirillum spp. + Azoarcus spp. + Azorhizobium spp.); and two mycorrhizal fungal-bacterial consortia, viz. (ii) Rhizophagus irregularis + Azotobacter vinelandii, and (iii) R. irregularis + Bacillus megaterium + Frateuria aurantia, and comparisons were made with noninoculated controls. We demonstrate that all the biofertilizers significantly enhanced plant growth and nitrogen accumulation during stem elongation and heading, but this was translated into only small grain yield gains (+1%-4% vs controls). The total gluten content of the flour was not affected, but in general biofertilization significantly upregulated two high-quality protein subunits, i.e., the 81 kDa high-molecular-weight glutenin subunit and the 43.6 kDa low-molecular-weight glutenin subunit. These effects were associated with increases in the rhizosphere microbial biomass and the activity of enzymes such as b-glucosidase, a-mannosidase, b-mannosidase, and xylosidase, which are involved in organic matter decomposition, particularly when Rhizophagus irregularis was included as inoculant. No changes in microbial biodiversity were observed. Our results suggest that seed-applied biofertilizers may be effectively exploited in sustainable wheat cultivation without altering the biodiversity of the resident microbiome, but attention should be paid to the composition of the microbial consortia in order to maximize their benefits in crop cultivation.

Morphological and biochemical changes in maize under drought and salinity stresses in a semi-arid environment, 2019

This study investigated some morphological and biochemical responses of maize to drought and sali... more This study investigated some morphological and biochemical responses of maize to drought and salinity
in open field in Tunisia with the aim of gaining insights into tolerance mechanisms. After seedling
emergence, five treatments were applied until maturity: optimal water supply (control, 100% of maximum
evapotranspiration - ETM); irrigation at 70% ETM (moderate drought) and at 35% ETM (severe
drought); optimal supply of water containing 3 g NaCl L1 (moderate salinity) and 6 g NaCl L1 (severe
salinity). Here, we demonstrated that extreme drought and salinity severely decreased the leaf area
(74% and 55%, respectively) and the above-ground biomass (35% and 31%, respectively) at
silking stage, indicating that the photosynthetic leaf apparatus is highly sensitive and that drought has
a greater effect than salinity. Grain yield losses were also exacerbated under extreme stress conditions,
viz. severe drought (85% versus controls) and severe salinity (73%), while productivity under moderate
salinity approximated that of moderate drought, possibly due to increases in leaf chlorophyll
and carotenoid content and K/Na ratio. The leaf area and its relative water content were positively correlated
with grain yield under both salinity and drought stresses, and may therefore be used as
markers for effective screening of maize genotypes for better stress tolerance.

Wood biochar produces different rates of root growth and transpiration in two maize hybrids (Zea mays L.) under drought stress, 2018

This study investigated the effects of wood-derived biochar (BC) applied at 1% to a C-poor silty-... more This study investigated the effects of wood-derived biochar (BC) applied at
1% to a C-poor silty-loam soil in the drought-tolerant (D24) and in the
drought-sensitive (P1921) Pioneer Hi-Bred maize hybrids in pot and field
trials (NE Italy). D24 had better growth than P1921 under rain-fed conditions
without irrigation and soil amendment. The addition of biochar increased
root growth in D24 (+38% root area) and decreases it in P1921 (−9%) at the
silking stage, while the fraction of finer roots (<250 μm diam.) was reduced
in D24 and increased in P1921. This led both hybrids to maintain the
maximum transpiration at a lower fraction of transpirable soil water (from
82% to 45% in D24, and from 46% to 22% in P1921). There were no
significant variations in plant nutrient contents, productivity and in the
protein and starch contents of the grains, whereas the lipid content was
reduced by biochar, particularly in P1921 (2.6% vs. 3% DW, −13%).
We conclude that biochar can be profitably used to enhance drought
tolerance in maize, possibly due to improvements in the physicochemical
characteristics and the water content of treated soils, although
maximum benefits are expected in drought-tolerant hybrids through
increased root elongation and transpiration.

Frontiers in Plant Science, 2019

Waterlogging is a severe abiotic stressor causing significant growth impairment and yield losses ... more Waterlogging is a severe abiotic stressor causing significant growth impairment and
yield losses in many crops. Maize is highly sensitive to the excess of water, and
against the background of climate change there is an urgent need for deeper
insights into the mechanisms of crop adaptation to waterlogging. In the present study,
changes in maize morphology at the 4–5 leaf stage and the expression of three
candidate genes for flooding tolerance in plants subjected to six continuous days of
waterlogging were recorded in 19 commercial hybrids and in the inbred line B73, with
the aim of investigating the current variability in cultivated hybrids and identifying useful
morphological and molecular markers for screening tolerant genotypes. Here it was
demonstrated that root parameters (length, area, biomass) were more impaired by
waterlogging than shoot parameters (shoot height and biomass). Culm height generally
increased in stressed plants (by up to C24% vs. controls), while shoot biomass was
significantly reduced in only two hybrids. Root biomass was reduced in all the hybrids, by
an average of 30%, and significantly in 7 hybrids, while root length and area were even
more severely reduced, by 30–55% vs. controls, depending on the hybrid. The earlier
appearance of aerial roots seemed to be associated with greater root injuries. In leaves,
the transcript of the PFP enzyme (phosphofructokinase), which is involved in glycolytic
reactions, was markedly up-regulated (up to double the values) in half the waterlogged
hybrids, but down-regulated in the others. The transcript of CYP81D8 (ROS-related
proteins) in waterlogged plants exhibited relevant increases or strong decreases in level,
depending on the hybrid. The transcript of the AOX1A gene, coding for a mitochondrial
respiratory electron transport chain-related protein, was markedly down-regulated in all
the treated hybrids. Expression analysis of these genes under extreme waterlogging only
partially correlate with the shoot and root growth impairments observed, and AOX1A
seems to be the most informative of them.

Industrial pasta is commonly made from mixtures of semolina from different durum wheat varieties,... more Industrial pasta is commonly made from mixtures of semolina from different durum wheat varieties, and there is a very low market presence of mono-varietal pasta from local, short supply chains. In this work, dough rheological properties and pasta quality traits of the new durum wheat cv. Biensur, which has a high HMW/LMW-GS ratio, were evaluated with a view to developing short-chain, mono-varietal pasta production in NE Italy. Chemical and sensory analyses on shortcut pasta, viz. tubetti, made with semolina from cv. Biensur at two drying temperatures revealed that it has good technological characteristics and stability, excellent cooking and sensory properties, and is comparable to the high-quality commercial reference cv. Aureo. We conclude that Biensur provides farmers and traders with new market opportunities and offers improvements to the environmental and economic sustainability of the durum wheat chain.

Sustainability, 2018

This study investigated the effects of a commercial biofertilizer containing the mycorrhizal fung... more This study investigated the effects of a commercial biofertilizer containing the mycorrhizal fungus Rhizophagus irregularis and the diazotrophic N-fixing bacterium Azotobacter vinelandii on root and shoot growth, yield, and nutrient uptake in common wheat (Triticum aestivum L.) in order to improve the sustainable cultivation of this widespread crop. The trials were carried out in controlled conditions (rhizoboxes) and in open fields over two years to investigate the interaction between inoculation and three doses of nitrogen fertilization (160, 120 and 80 kg ha −1) in a silty-loam soil of the Po Plain (NE Italy). In rhizoboxes, efficient root colonization by R. irregularis was observed at 50 days after sowing with seed inoculation, together with improved root tip density and branching (+~30% vs. controls), while the effects of post-emergence inoculation by soil and foliar spraying were not observable at plant sampling. In the open, field spraying at end tillering significantly increased the volumetric root length density (RLD, +22% vs. controls) and root area density (+18%) after about two months (flowering stage) in both years under medium and high N fertilization doses, but not at the lowest N dose. In absence of inoculation, RLD progressively decreased with increased N doses. Inoculation had a negligible effect on grain yield and N uptake, which followed a typical N dose-response model, while straw Zn, P, and K concentrations were seldom improved. It is concluded that medium-high N fertilization doses are required to achieve the target yield and standards of quality (protein contents) in wheat cultivation, while the use of this mixed VAM-PGPR biofertilizer appears to be a sustainable mean for minimizing the adverse effects of chemical N fertilizers on root expansion and for improving the uptake of low-mobility nutrients, which has potentially relevant environmental benefits.

Plant growth regulation, 2018

The maize brachytic2 (br2) gene encodes a protein homologous to the Arabidopsis ABCB1 protein, wh... more The maize brachytic2 (br2) gene encodes a protein homologous to the Arabidopsis ABCB1 protein, which actively transports
chemically diverse substrates across cellular membranes. This includes indole-3-acetic acid (IAA), the most abundant natural
form of auxin, a key regulator of plant growth and tropisms. Defects in auxin transport are responsible for the short stature
of br2 mutants. We describe a novel br2 mutant allele present in NC238, an inbred maize of medium stature and demonstrate
that the mutant allele br2-NC238 is caused by the insertion of a novel transposon in intron IV of the br2 gene. A tall
revertant of NC238 (NC238-rev) appeared spontaneously as a result of excision of the transposon from the br2 gene. This
event yielded two completely isogenic versions of the NC238 inbred, one brachytic (NC238-ref) and one tall (NC238-rev).
The presence of the transposon in br2-NC238 alters normal splicing of the transcript, producing several splicing forms. One
splicing form, ABCB1-T02, was abundantly expressed in NC238-ref, while its expression was very weak in tall NC238-rev
plants. Differences between NC238-rev and NC238-ref were also detected in the expression pattern of auxin transporter
genes. Morphological changes associated with the br2-NC238 mutant allele included reduced length and increased diameter
of the lower internodes. The shortening of plant stature was confirmed in the B73 genetic background by introgression of
the br2-NC238. Our results demonstrate that br2-NC238 reduces plant height without altering other morphological traits,
and might thus be useful in maize breeding programs when reduction of stature is desired.

Molecules, 2018

In an open field trial on two agricultural soils in NW Italy, the impact of two seed-applied bios... more In an open field trial on two agricultural soils in NW Italy, the impact of two seed-applied biostimulants on the rhizosphere bacterial community of young maize plants was evaluated. The 16S rDNA profiling was carried out on control and treated plant rhizosphere samples collected at the 4-leaf stage and on bulk soil. In both soils, the rhizospheres were significantly enriched in Proteobacteria, Actinobacteria, and Bacteriodetes, while the abundances of Acidobacteria, Cloroflexi and Gemmatimonadetes decreased compared with bulk soil. Among the culturable bacteria genera that showed an increase by both biostimulants, most are known to be beneficial for nutrient uptake, such as Opitutus, Chryseolinea, Terrimonas, Rhodovastum, Cohnella, Pseudoduganella and the species Anaeromyxobacter dehalogenans; others are known to be involved in root growth, such as Niastella, Labrys, Chloroflexia and Thermomonas; or in plant defence, such as Ohtaekwangia, Quadrisphaera, Turneriella, and Actinoallomurus. Both biostimulants were also found to stimulate gen. Nannocystis, a potential biocompetitive agent against aflatoxigenic Aspergillus moulds. Under controlled conditions, both biostimulants enhanced the shoot and root biomass at the 4–5 leaf stage. We conclude that the biostimulants do not decrease the biodiversity of the microbial community rhizosphere of young maize plants, but stimulate rare bacterial taxa, some involved in plant growth and pathogen resistance, a result that may have implications in improving crop management.

Journal of the Science of Food and Agriculture, 2018

BACKGROUND: With the increasing demand for high-quality foodstuffs and concern for environmental ... more BACKGROUND: With the increasing demand for high-quality foodstuffs and concern for environmental sustainability,
late-season nitrogen (N) foliar fertilization of common wheat is now an important and widespread practice. This study
investigated the effects of late-season foliar versus soil N fertilization on yield and protein content of four varieties of durum
wheat, Aureo, Ariosto, Biensur and Liberdur, in a three-year field trial in northern Italy.
RESULTS: Variations in low-molecular-weight glutenins (LMW-GS), high-molecular-weight glutenins (HMW-GS) and gliadins
were assessed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). It was found that N applied to the
canopy did not improve protein rate compared with N application to the soil (general mean 138mg g−1), but moderately
increased productivity in the high-yielding varieties Liberdur and Biensur (three-year means 7.23 vs 7.13 and 7.53 vs 7.09 t
ha−1 respectively). Technological quality was mainly related to variety choice, Aureo and Ariosto having higher protein rates
and glutenin/gliadin ratios. Also found was a strong ‘variety × N application method’ interaction in the proportions of protein
subunits within each class, particularly LMW-GS and gliadins. A promising result was the higher N uptake efficiency, although
as apparent balance, combined with higher HMW/LMW-GS ratio in var. Biensur.
CONCLUSION: Late-season foliar N fertilization allows N fertilizer saving, potentially providing environmental benefits in the
rainy climate of the northern Mediterranean area, and also leads to variety-dependent up-regulation of essential LMW-GS and
gliadins. Variety choice is a key factor in obtaining high technological quality, although it is currently associated with modest
grain yield. This study provides evidence of high quality in the specific high-yielding variety Biensur, suggesting its potential as
amono-varietal semolina for pasta production.

Frontiers in Plant Science, 2017

Most crops are routinely protected against seed-born and soil-borne fungal pathogens through seed... more Most crops are routinely protected against seed-born and soil-borne fungal pathogens through seed-applied fungicides. The recently released succinate dehydrogenase inhibitor (SDHI), sedaxane R , is a broad-spectrum fungicide, used particularly to control Rhizoctonia spp., but also has documented growth-enhancement effects on wheat. This study investigates the potential biostimulant effects of sedaxane and related physiological changes in disease-free maize seedlings (3-leaf stage) at increasing application doses (25, 75 and 150 µg a.i. seed −1) under controlled sterilized conditions. We show sedaxane to have significant auxin-like and gibberellin-like effects, which effect marked morphological and physiological changes according to an approximate saturation dose-response model. Maximum benefits were attained at the intermediate dose, which significantly increased root length (+60%), area (+45%) and forks (+51%), and reduced root diameter as compared to untreated controls. Sedaxane enhanced leaf and root glutamine synthetase (GS) activity resulting in greater protein accumulation, particularly in the above-ground compartment, while glutamate synthase (GOGAT) activity remained almost unchanged. Sedaxane also improved leaf phenylalanine ammonia-lyase (PAL) activity, which may be responsible for the increase in shoot antioxidant activity (phenolic acids), mainly represented by p-coumaric and caffeic acids. We conclude that, in addition to its protective effect, sedaxane can facilitate root establishment and intensify nitrogen and phenylpropanoid metabolism in young maize plants, and may be beneficial in overcoming biotic and abiotic stresses in early growth stages.

Journal of Cleaner Production , 2018

A novel procedure for isoflavones extraction from soybean seeds using the “green solvent” water w... more A novel procedure for isoflavones extraction from soybean seeds using the “green solvent” water was set-up for its future industrial up-scaling. The optimized processing flow-scheme proposed here consists of a 1:5 flour weight-to-water volume ratio mixed by vertical stirrers for 6 min. at 40 °C, with a final 12000-rpm centrifugation, and subsequent lyophilization to ensure stability and easy dosage of the extracts. Results showed that preliminary UV-C light flour irradiation for at least 1 h can improve isoflavones extraction and reduce anti-nutritional factors. Principal component analysis (PCA) and discriminant factorial analysis (DFA) highlighted specific operational conditions, such as extraction volume and time, UV time exposure, and centrifugation speed, for preferential extraction of specific isoflavones. The extraction efficiency varied according to variety choice within a range of 40-73%, possibly due to the relative abundance of the most water-soluble malonyl forms of isoflavones. As the extracts showed promising high stability under freezing and lyophilization conditions, it is concluded that, this ecofriendly extraction approach with can be successfully scalable, helping to save time and energy and obviating at disposal problems in the soy nutraceutical chain.

Agriculture, Ecosystems and Environment, Sep 1, 2017

The use of plant growth-promoting rhizobacteria (PGPR) meets the current need to reduce nitrogen ... more The use of plant growth-promoting rhizobacteria (PGPR) meets the current need to reduce nitrogen input in order to attain greater sustainability in the production of crops, particularly cereals. This study investigated whether a commercial bio-fertiliser containing a consortium of PGPR and N-fixing bacteria (Azospirillum spp., Azoarcus spp. and Azorhizobium spp.) affects shoot and root growth, N accumulation and grain yield in common wheat (Triticum aestivum L.).
Trials were conducted in a fertile, silty loam soil, firstly in rhizoboxes, by applying bacteria either as a seed- coating inoculum or by foliar + soil spraying, and then in the field by spraying the canopy at the tillering stage with decreasing levels of N fertilisation (160, 120 and 80 kg/ha) in two consecutive years. Culm height, leaf chlorophyll content, nitrogen accumulation and yield were recorded above ground, while below ground Root Length Density (RLD) patterns were investigated by soil coring and image analysis at the flowering stage. Environmental Scanning Electron Microscope (ESEM) imaging revealed an excellent ability of bacteria to adhere to the surface of intact leaves and roots, and to colonise both leaf mesophyll and root vascular tissues in aseptic conditions. Bacteria increased the number of root tips and ramifications (+65% vs. non-inoculated controls) in sterilised rhizobox soil, regardless of the method of application, and the volumetric root length density in the open field with medium (+29%) and high (+11%) N supply, resulting in greater N accumulation (about +25 kg ha−1). Although the N dose had clear positive effects, no significant variations in grain yield (only + 1–3% vs. non-inoculated controls) or other agronomic parameters could be ascribed to bacteria inoculation.
The conclusion drawn is that the use of a combination of PGPR and N-fixing bacteria offers an opportunity to improve root growth in wheat and increase plant resilience to environmental stresses, and helps to reduce N losses from agricultural ecosystems thereby offering partial fertiliser savings within crop rotations.

Journal of Plant Pathology, May 2017

Blackline disease, caused by Cherry leaf roll virus (CLRV), is considered a serious threat limiti... more Blackline disease, caused by Cherry leaf roll virus (CLRV), is considered a serious threat limiting English walnut (Juglans regia) production in Italy and the EU if walnut species other than J. regia e.g. ‘Paradox’ hybrid (J. regia × J. hindsii), French hybrid (J. regia × J. major or J. regia × J. nigra) or northern California black walnut (J. hindsii) are used as the rootstock. The virus transmissibility by pollen as well as latent infections can result in the spread of CLRV- contaminated propagative material, which is a major means of the virus dispersal by human activities. In 2014 and 2015 to ascertain the presence and the distribution of blackline symptoms in commercial orchards and to provide a description of the symptomatology, visual inspections and analyses were carried out on 1,684 walnut trees in four different intensively managed grafted English walnut orchards in northeast Italy (Veneto Region). Trees with clear blackline symptoms at the scion-rootstock junction, often associated with general decline of the plant, were found only in one commercial orchard in northeast Italy on trees older than ten years of cvs. ‘Tulare’ and ‘Chandler’, grafted onto ‘Paradox’ rootstock. To our knowledge this is the first report of CLRV (blackline) decline and death in a commercial walnut orchard in Italy.

Annals of Botany, Feb 28, 2017

Aims: Oak decline is a complex phenomenon, characterized by symptoms of canopy transparency, bark... more Aims: Oak decline is a complex phenomenon, characterized by symptoms of canopy transparency, bark cracks and root biomass reduction. Root health status is one of the first stress indicators, and root turnover is a key process in plant adaptation to unfavourable conditions. In this study, the combined effects of decline and thinning were evaluated on fine root dynamics in an oak forest adjoining the Italian Pre-Alps by comparison of acute declining trees with non-declining trees, both with and without thinning treatment of surrounding trees. Methods: Dynamics of volumetric root length density (RLD V ) and tip density (RTD V ), root tip density per unit length of root (RTD L ), diameter, branching index (BI) and mycorrhizal colonization were monitored by soil coring over 2 years as possible descriptors of decline. Key results: At the beginning of the experiment, the relationship between canopy transparency and root status was weak, declining trees having slightly lower RLD V (-20 %) and RTD V (-11 %). After a 1 year lag, during which the parameters were almost unaffected, BI and RLD V , together with tip density, tip vitality and mycorrhizal colonization, became the descriptors most representative of both decline class and thinning. Thinning of declining trees increased RLD V (+12 %) and RTD V (+32 %), but reduced tip mycorrhizal colonization and vitality over time compared with non-thinned trees, whereas the opposite occurred in healthy trees, together with a marked decrease in branching. After thinning, there was an initial reduction in the structure of the ectomycorrhizal community, although recovery occurred about 10 months later, regardless of decline severity. Conclusions: Decline causes losses of fine root length, and a moderate recovery can be achieved by thinning, allowing better soil exploration by oak roots. The close correlation between root vitality and mycorrhizal colonization and their deterioration after thinning indicates that decline does not benefit from reduced root competition, excluding the hypothesis of limited water and nutrient availability as a possible cause of the syndrome in this forest.

Italian Journal of Agrometeorology, Dec 2016

In a field trial in Tunisia, the effects of drought and salinity on maize phenology, shoot and ro... more In a field trial in Tunisia, the effects of drought and salinity on maize phenology, shoot and root characteristics, and productivity were examined after the following treatments: two sub-optimal irrigation levels (70% and 35% ETM), with standard water quality; two levels of water salinity (3 and 6 g NaCl L-1) at 100% ETM, compared with optimal water supply (100% ETM, control) and standard quality. We demonstrate here that both drought and salinity greatly change phenology, with the result that both silking and physiological maturity are reached much earlier. The extreme condition is the most severe drought, resulting in 10 and 12 days anticipation respectively, although with compromised yield (-84% vs. controls). Irrigation at 70% ETM turned out to be a sustainable practice, with limited changes in phenology but with a fall in yield of 22%. The vegetative habitus of the plants was very stable towards salinity, although yield losses were considerable, i.e., 25% and 73% at moderate and high salinity, respectively, due to marked reduction of cob fertility. Extreme drought impaired root weight, whereas salinity did not affect this root trait. Principal component and discriminant analyses identified above-ground the number of kernels per ear and kernel weight, and below-ground the number of main roots as the key traits in sustaining maize productivity. We conclude that moderate water or salinity stress allows silking time to be scheduled, for more efficient water management in the sensitive growth stages of maize. Thorough screening of genotypes at below-ground level also seems to be helpful to improve water use efficiency and tolerance to conditions of extreme drought and salinity.

Industrial Crops and Products , Nov 15, 2016

Within a framework of renewed interest in crambe (Crambe abyssinica Hochst ex R.E. Fries) sourcin... more Within a framework of renewed interest in crambe (Crambe abyssinica Hochst ex R.E. Fries) sourcing raw materials for the bio-based industry, the adaptability and productive performances of this oil crop have been evaluated under contrasting Mediterranean environments (i.e., a fertile site in the northern part of Po valley vs. a semi-arid site of southern Sicily) during two consecutive growing seasons, aiming at its pos- sible stable introduction in this area. The trial set in northern Italy compared three commercial varieties of crambe (Galactica, Nebula and Mario) in spring sowing, while in southern Italy only the var. Mario was tested with autumn sowing. Regardless of location and variety, thermal time for maturity was quite stable (1200–1400 ◦C), and the crop provided satisfactory seed yields (grand mean 2.29 Mg hulled seeds/ha), with average oil content of ∼400 g/kg (on dehulled seeds) and ∼52% of erucic acid. Significantly higher seed and oil yields were reached in northern than in southern Italy. Furthermore, crambe thermal use efficiency (THUE) was also higher in the north than in the south, possibly due to better environmental adaptability of the crop. The limited intraspecific variability within crambe was confirmed, with better productive performances showed by the domestic selection Mario. Promising traits were revealed in Nebula, showing greater seed weight, root length density and area, and thinner roots, although the root growth of crambe was generally modest compared with modern high erucic acid rapeseed hybrids. Avail- able crambe varieties could be efficiently included in crop rotations across a wide range of environments within the Mediterranean basin. The short growth cycle represents an outstanding added value for this species, allowing the avoidance of prolonged drought and heat stress typical of late spring/early summer months under the Mediterranean climate. However, increased yields are needed to meet the market requests; nonetheless, the little genetic variability suggests that there is large scope for future breeding improvements, maybe exploiting advanced techniques to improve the existing genetic resources.

Agronomy, 2021

Agronomy, 2020

Frontiers in Plant Science, 2020

Morphological and biochemical changes in maize under drought and salinity stresses in a semi-arid environment, 2019

Wood biochar produces different rates of root growth and transpiration in two maize hybrids (Zea mays L.) under drought stress, 2018

Frontiers in Plant Science, 2019

Sustainability, 2018

Plant growth regulation, 2018

Molecules, 2018

Journal of the Science of Food and Agriculture, 2018

Frontiers in Plant Science, 2017

Journal of Cleaner Production , 2018

Agriculture, Ecosystems and Environment, Sep 1, 2017

Journal of Plant Pathology, May 2017

Annals of Botany, Feb 28, 2017

Italian Journal of Agrometeorology, Dec 2016

Industrial Crops and Products , Nov 15, 2016

The topic of my PhD research addresses the study on the effects that some new sustainable crop ma... more The topic of my PhD research addresses the study on the effects that some new sustainable crop management practices have on enhancing root growth in two globally important cereal crops, wheat and maize. The structure of the thesis consists of five chapters, corresponding to as many manuscripts already published (2 of 5) or on the way to be published in international scientific journals. In detail, in the first and second chapter were studied the application effects of plant growth promoting microorganisms (PGPMs) on common wheat. The aspects taken under study after their inoculation were: the ability of selected endophityc bacteria and mycorrhizal fungi to colonize and interact with plant organs, the effects on root growth, the promotion of shoot development, the nutitional improvement by increasing N fixation and nutrient availability, the effects on grain yield and other agronomic parameters and finally the environmental significance by evaluating the possibility of cutting chemical fertilization. Microscope investigations revealed an excellent ability of bacteria to adhere to the surface of intact leaves and roots, and to colonize both leaf mesophyll and root vascular tissues in aseptic conditions. Also the mycorrhizal fungus was able to colonize wheat roots efficiently. Bacteria increased the number of root tips and ramifications in sterilized rhizobox soil, regardless of the method of application, and the volumetric root length density in the open field with medium and high N supply, resulting in greater N accumulation. Although the N dose had clear positive effects, no significant variations in grain yield or other agronomic parameters could be ascribed to bacteria inoculation. The arbuscular mycorrhizal fungus allowed remarkable increases in volumetric root length density and root area density at flowering stage at medium and high N fertilization rates in both years, but not a low N rate. While inoculation had a negligible effect on grain yield, which followed a typical N dose-response model, improved uptake of N and other nutrients, particularly P and Zn were recorded at any fertilization rate, although only seldom significant. Last three chapters aimed at investigating the potential rooting activity on maize plants of the recently market-introduced seed-applied fungicide Sedaxane®, a novel succinate dehydrogenase complex II inhibitor (SDHI) against soil-borne pathogenic fungi. Laboratory investigations demonstrated that sedaxane has significant auxin-like and gibberellin-like effects, which induced marked morphological and physiological root changes according to an approximate saturation dose-response model. Sedaxane enhanced leaf and root glutamine synthetase (GS) activity resulting in greater protein accumulation, particularly in the shoot, while glutamate synthase (GOGAT) activity remained almost unchanged. Sedaxane also improved leaf phenylalanine ammonia-lyase (PAL) activity, which may be responsible for the increase in shoot antioxidant activity (phenolic acids), mainly represented by p-coumaric and caffeic acids. Under controlled conditions in a greenhouse we evaluated the root growth enhancement side-effect of sedaxane, regardless of the main protective action against pathogenic fungi, in pot-cultivated maize plants subjected to both biotic and abiotic stress conditions in the early phenological stages. The secondary effect of sedaxane on root growth was detectable both in absence and with high Rhizoctonia solani pressure, but it was more evident in the last situation. Significant enhancements in root biomass, length, area and tips quantity were observed, but also shoot parameters, like leaf chlorophyll content and total biomass. Seed-treated plants highlighted positive responses to both adverse growing conditions performed in the experiments reported in the last chapter, a decreasing soil fertility and a drought stress during early phenological stages. Results showed increased growth of shoot, with higher SPAD values, nutrient uptake and antioxidant activity (phenolic acids), as well as a greatly enhanced root growth than controls. Particularly under severe water stress condition, these parameters did not show marked differences from controls, but plants from treated seeds with fungicide were able to maintain a higher rate of transpiration to lower value of transpirable water in the soil.

La coltivazione del noce da frutto in forma promiscua è diffusa in tutta Italia. Fino a pochi ann... more La coltivazione del noce da frutto in forma promiscua è diffusa in tutta Italia. Fino a pochi anni fa l’intera produzione nazionale di noci derivava esclusivamente da un’agricoltura marginale mentre, allo stato attuale, la coltivazione del noce è in espansione soprattutto nel nord del Paese. Nel Veneto, in particolare, questa coltivazione è caratterizzata da grandi aziende con impianti altamente specializzati che stanno facendo fronte all’elevata richiesta del mercato interno del prodotto. Tuttavia, malgrado l’aumento della produzione nazionale, l’Italia è importatrice di noci e in generale di frutta secca. Durante l’estate del 2011 ho svolto il mio Tirocinio pratico applicativo universitario presso un’azienda specializzata nella coltivazione di noci da frutto. Nel corso dell’esperienza ho rilevato l’importanza della difesa fitosanitaria, che è fondamentale per la produzione di nocidi qualità. Le avversità che colpiscono il noce da frutto sono provocate da numerosi patogeni e fitofagi tra i quali spiccano per la loro pericolosità la batteriosi del noce e la carpocapsa. La quasi totalità dei titolari delle aziende produttrici di noci del Veneto fa parte di Organizzazioni di Produttori e aderiscono al Disciplinare di Lotta Integrata regionale che consente l’ottenimento della certificazione di Filiera Controllata. Con questo lavoro ho voluto quindi definire lo stato attuale della lotta integrata del noce da frutto nella regione Veneto, specificando gli interventi attuati nella realtà aziendale sede del mio tirocinio. Le normative vigenti non consentono l’impiego di adeguati mezzi di lotta chimica contro le avversità parassitarie del noce; nel prossimo futuro, considerando l’imminente applicazione di nuove disposizioni legislative, si prevedono ulteriori ripercussioni negative sulla possibilità di attuare efficaci interventi di difesa del noce da frutto.

Growth and metal uptake in alimurgic species of the Veneto region. Metal pollution is a major pr... more Growth and metal uptake in alimurgic species of the Veneto region.

Metal pollution is a major problem for agricultural soils and is receiving increasing attention for the environmental and health risks that it poses. Metals are present in fertilizers, pesticides and contaminated irrigation water and, unlikely organic pollutants, are not degraded by soil microflora. Some elements (e.g., Cd, Pb) are toxic to plants and animals per se, whereas others (e.g., Co, Cu, Zn) are essential at certain amounts for sustaining metabolic functions, becoming noxious only at high rates.
The present study was carried out in controlled environment (pots) and in the open, in sites of the Padova province, and aimed at ascertaining the metal uptake ability of some alimurgiche perennial species belonging to the families Asteraceae (Cichorium intybus L., Sonchus oleraceus L., Taraxacum officinale L. and Tragopogon porrifolius L.) and Polygonaceae (Rumex acetosa L.). These wild herbs are commonly collected as edible plants, and are now object of programs for conservation, protection and enhancement of biodiversity.
The experiment intended to verify the capacity of accumulation of essential (Co, Cu, Zn) and toxic (Cd, Pb) metals in various plant organs when grown on an artificial metal- enriched soil in pots or at sites at risk of pollution, in order to assess the potential food hazard or biofortification on the one hand, and the possible use in green technologies for soil remediation and management.
All species showed a good tolerance to high soil contamination rates, especially at aboveground (biomass and SPAD values), whereas a great reduction of root length was observed in T. officinale e S. oleraceus. All species showed a good metal accumulation, but still below to that of hyperaccumulator plants.
The high translocation of Zn and Cd from roots to shoot (coefficient of translocation of 2.6 and 2.3 respectively) suggests the possible use of these plants in phytoextraction, especially T. porrifolius and C. intybus, while the appreciable accumulation of Pb and Cu in tap-roots (respectively 15.6 and 85,7 mg kg-1) suggests their application to in planta phytostabilization. R. acetosa and T. officinale showed the highest metal uptake per plant (1.5 and 0.6 mg, respectively).
Considering a density of 15-20 plants m-2 for R. acetosa, and 40-60 for T. porrifolius, up to a maximum of 230 g of metals per hectare may be stored in plant tissues.
The soil collected from various sites in Padova (ex-landfill at Roncajette - Ponte San Nicolò, field ditch at Montà, roadside at Legnaro) was generally un-contaminated, with the exception of a high concentration of Pb detected at the roadside in Legnaro. Despite the low metal levels in the landfill soil, leaves of T. officinale were rich in Cd and Pb, and taproots in Cu.
Plants grown in contaminated soil were enriched in essential mineral nutrients such as Zn and, to a lesser extent, Co. However, leaf Pb and Cd often exceeded the maximum thresholds allowed by the EU, thus making the continuative consumption of these species hazardous when they are grown in contaminated environments.

5th European Agroforestry Conference, 2021

Soybean cultivation in Italy has developed since the 80s mainly for animal feeding, thanks to its... more Soybean cultivation in Italy has developed since the 80s mainly for animal feeding, thanks to its high protein content, and for human uses mainly for oil production. Agroforestry practices are becoming increasingly important as a means to improve carbon sequestration and mitigate climate change. Soybean is a crop that could fit well with this new agricultural approach, especially because it is a nitrogen fixing species. Soybean is also increasingly used for nutraceutical production. Isoflavones are the most important nutraceutical compounds, and are used for their antioxidant activity and anticholesterolemic effect.

5th European Agroforestry Conference, 2021

Agroforestry systems (AFS) are receiving renewed attention in temperate regions, as agricultural ... more Agroforestry systems (AFS) are receiving renewed attention in temperate regions, as agricultural systems able to enhance crop resilience towards climate scenarios of increasing mean temperatures and shifting rainfall patterns. The shortening of crop growing cycle and the reduction of grain ripening duration are the main effects of climate change which leads to yield and quality impairments in cereal production (Ren et al., 2019). In silvoarable AFS, among the main factors affecting the development and yield of the cultivated intercrops there are the design and management of the system, which strongly influence the availability of resources such as light, nutrients and water, and the adaptability of the crop to the specific growing conditions (Pardon et al., 2018). Considering that actual quantitative data in temperate AFS is limited, especially with a mature tree component, artificial shading is an interesting experimental tool to mimic the effect of tree rows on the intercrop in order to investigate different shading intensity and dynamics on a limited space, and to isolate the light factor from other potential interactions between the two components of
the AF system (Artru et al., 2017). In this study we investigated the effect of artificial shading with two levels of light reduction on the growth and yield of three varieties of common wheat: two old varieties originated in the NE of Italy, compared with a reference modern variety, in order to evaluate their future implementation in alley cropping AFS.

Proceedings of the 49th Conference of the Italian Society of Agronomy, 2020

Nitrogen application through foliar spraying is widely recognised as an efficient and sustainable... more Nitrogen application through foliar spraying is widely recognised as an efficient and sustainable agronomic practice to improve the protein content in common wheat (Triticum aestivum L.) (Gooding and Davies, 1992). However, up to date, only few studies have investigated the effects of this practice compared to conventional soil fertilisation, although late-season (between booting and anthesis) foliar supply of small doses of nitrogen has become common practice (Readman et al., 2002). In this framework, this study compared growth, yield and grain quality of a bread-making wheat variety fertilised by low N rates entirely applied by foliar applications with UAN (urea ammonium nitrate) or urea, compared to conventional soil fertilisation at a common higher rate.

Proceedings of the 49th Conference of the Italian Society of Agronomy, 2020

Increased summer temperatures due to global warming are expected to greatly damage maize, and the... more Increased summer temperatures due to global warming are expected to greatly damage maize, and the associated drought stress during flowering stage can reduce ovary fertilization and yield (Bassetti and Westage, 1993). An anticipation of sowing date may be a strategy to overcome drought stress during flowering, but it could be limited by initial low temperatures, excess of rainfall and cold return. It is known that sub-optimal temperatures strongly reduce leaf initiation (Warrington and Kanemasu, 1983), photosynthesis activity (Nie et al., 1992) and root development in maize (Barlow and Adam, 1989).
Seed treatment with fungicides is a useful tool to prevent pathogen injury, and some a.i. can also have a positive impact on plant development. Previous study described the positive effects of some fungicides, such as Sedaxane, classified as SDHI (succinate dehydrogenase inhibitor), on root growth and development, playing a biostimulant role (Dal Cortivo et al., 2017).
The aim of this experiment was to evaluate the biostimulant effect of the commercial fungicides Maxim XL and Maxim Quattro, alone or in combination with Vibrance, which contain the a.i. Sedaxane, on root system under three different temperature regimes.

Proceedings of the 49th Conference of the Italian Society of Agronomy, 2020

Under intensive agriculture, crop yield stability has been increasingly reduced in the last decad... more Under intensive agriculture, crop yield stability has been increasingly reduced in the last decades due to the negative impact of natural resources depletion and climate change, particularly extreme temperatures and water scarcity. Agroforestry farming, with the integration of woody vegetation and crops on the same agricultural land, has high potential to improve crop resilience to climate change and provide a more stable provision of agricultural products, while contributing to increase ecosystem services delivery such as enhancing resources use efficiency (Jose et al., 2009). Intercropping with tree species for timber production was largely practiced in the agricultural lands of Italy until the ‘70s, but the intensification of agriculture has led to remove trees in order to boost monoculture practices (Paris et al., 2019). In this study we investigated the impact of row-arranged poplar and oak trees on growth, yield and quality of a winter cereal and a legume crop cultivated in the alley, in order to assess the potential of this alley-cropping system to enhance crop resilience to climate change and ensure more stable yields.

XLVIII Conference of Italian Society for Agronomy , 2019

This study investigated whether a commercial bio-fertiliser containing a consortium of PGPB affec... more This study investigated whether a commercial bio-fertiliser containing a consortium of PGPB affects root and shoot growth and N accumulation in common wheat. Trials were conducted firstly in rhizoboxes, applying bacteria either as a seed-coating inoculum or foliar+soil spraying, and then in the field by spraying bacteria to the canopy at tillering stage with decreasing N fertilisation (160, 120, 80 kg ha-1). Environmental scanning electron microscope (ESEM) imaging revealed their excellent ability to colonise plant surface and both leaf mesophyll and root vascular tissues. Bacteria increased the number of root tips and ramifications (+65% vs. non-inoculated) in sterilised pot soil and the root length density in the open field with medium (+29%) and high (+11%) N supply, resulting in greater N accumulation (about +25 kg ha-1). Although without yield benefits, the rooting power of these bacteria can help to reduce N losses from agro ecosystems and to save chemical fertilisers. Introduction Chemical fertilisers are commonly used to supply essential nutrients to soil-plant systems in a wide range of cultivated crops. However, the use of high amounts of chemical fertilisers, especially nitrogen, has raised environmental concerns in the current agricultural systems of industrialised countries. There is an urgent need to find safe, alternative fertilisation strategies in order to improve the sustainability of agro-ecosystems, especially in cereal cultivation, while at the same time retaining competitive crop yields. One potential method of attenuating the negative environmental impact of chemical fertilisers and pesticides is to apply plant growth promoting rhizobacteria (PGPR) as bio-fertilisers (Pérez-Montaño et al., 2014). These bacteria play a role in plant nutrition by exerting non-symbiotic N fixation, enhancing the availability of nutrients in the rhizosphere, such as phosphorus and iron, and increasing the root surface area through the production of hormones (Kumar et al., 2014). There is growing interest in the use of PGPR with cereals and various studies are demonstrating their beneficial role in the growth and yields of several crop species. However, several factors, such as plant genotype, bacteria species and strain, and agricultural practices may affect plant responses and the success of inoculation (Tahir et al., 2015). Against this background, the aim of this work was to study the effects on common wheat (Triticum aestivum L.) of a mixture of PGP-rhizobacteria and free-living N-fixing bacteria, i.e., Azospirillum spp., Azoarcus spp. and Azorhizobium spp., provided as a commercial formulation (TripleN ® , Mapleton Agri Biotec, Australia) suitable for use on a wide variety of field and tree crops. Effects on the root characteristics of young and mature plants, N accumulation, and yield were examined in controlled and open field experiments at the experimental farm of the University of Padua (NE Italy).

As soil metal contamination is rapidly increasing worldwide, mainly because of human activities, ... more As soil metal contamination is rapidly increasing worldwide, mainly because of human activities, phytomanagement of polluted land is becoming an environmentally sustainable and cost-effective option that can also produce biomass and energy as secondary utilities. Some Asteraceae and Polygonaceae species growing spontaneously as invasive weeds on natural and farmed land, which are considered medical or edible alimurgic species, have been identified to accumulate high above-ground levels of toxic elements, thanks to efficient root-to-shoot translocation. Most of them combine high adaptability to marginal soils with good shoot biomass, and many are metal indicator or hyperaccumulator species. In this study were investigated the shoot and root growth potential, metal uptake and translocation at the flowering stage of wild chicory (Cichorium intybus L.), common sowthistle (Sonchus oleraceus L.), salsify (Tragopogon porrifolius L.), common dandelion (Taraxacum officinale Web.) and garden sorrel (Rumex acetosa L.) in artificially highly Cd-Co-Cu-Pb-Zn-contaminated soil.

In un’ottica di miglioramento della sostenibilità della coltivazione del frumento tenero per l’ot... more In un’ottica di miglioramento della sostenibilità della coltivazione del frumento tenero per l’ottenimento di farine panificabili che possano rientrare nel marketing delle produzioni eco-compatibili, nel corso del 2013-14 è stata svolta una prima sperimentazione per verificare il livello di surrogabilità della concimazione azotata con trattamenti biofertilizzanti a base di micorrize e batteri azotofissatori.

The root systems in sustainable agricultural intensification, 2021