Papers by Stefano Mancuso
Plants, 2022
Few phytoremediation studies have been conducted under semi-arid conditions where plants are subj... more Few phytoremediation studies have been conducted under semi-arid conditions where plants are subjected to drought and/or salinity stress. Although the genus Salix is frequently used in phytoremediation, information regarding its tolerance of drought and salinity is limited. In the present study, Salix acmophylla Boiss. cuttings from three sites (Adom, Darom and Mea She’arim) were tested for tolerance to salinity stress by growing them hydroponically under either control or increasing NaCl concentrations corresponding to electrical conductivities of 3 and 6 dS m−1 in a 42-day greenhouse trial. Gas exchange parameters, chlorophyll fluorescence and concentration, and water-use efficiency were measured weekly and biomass was collected at the end of the trial. Root, leaf and stem productivity was significantly reduced in the Adom ecotype, suggesting that Darom and Mea She’arim are the more salt-tolerant of the three ecotypes. Net assimilation and stomatal conductance rates in salt-treate...
A technique was developed (1) to digitise grapevine leaves, (2) to split the images obtained in t... more A technique was developed (1) to digitise grapevine leaves, (2) to split the images obtained in the three components of the RGB (red, green and blue) colour system, obtain the fractal spectrum for each colour component of the leaf and (3) to calculate 15 different fractal parameters. The system, consisting of a scanning device, a personal computer and the code written in the C language, was then tested to characterize and identify 12 Sangiovese-related grapevine accessions. The results enabled us to distinguish between all accessions with a better discrimination than that obtained in previous studies with molecular markers or elliptic Fourier analysis. More, all the fractal parameters calculated for leaves of Sangiovese R10 grown in very different environments did not show any significant modification, revealing that fractal features can be considered environment-independent. The fractal analysis approach proposed, on the basis of the results obtained, gives the opportunity to verif...
Vitis: Journal of Grapevine Research, Jul 30, 2015
Advances in horticultural science, 2002
A b s t r a c t : The recent demand for quality foods and the necessity to develop low-input, env... more A b s t r a c t : The recent demand for quality foods and the necessity to develop low-input, envir o n m e n t a l l y friendly agronomic techniques has encouraged the use of cover cropping in vineyards, olive groves, and tree plantations for both fruit and timber. Research has indicated both positive and negative effects of cover crops when used with tree cultivation. Several cover crop species have been recognized as suitable for varying climates, soils and usage. Sward management was conducted in dif f e rent climates and agronomic conditions with subsequent contrasting results. These results will help to identify the most suitable cover crop for the various environments and tree species.
Arboriculture & Urban Forestry, 2000
The purpose of this study was to evaluate the effects of two different nursery production methods... more The purpose of this study was to evaluate the effects of two different nursery production methods and backfill compositions on tree performance after transplanting in the urban landscape.
Applied Sciences, 2020
Poplar and willow demonstrate great potential for the phytoextraction of trace elements (TEs) fro... more Poplar and willow demonstrate great potential for the phytoextraction of trace elements (TEs) from soils. In most cases, these species are managed as short-rotation coppice, producing high woody biomass yields, which could provide a valuable contribution toward reducing greenhouse gas emissions in the atmosphere. In the current study, we compared the TE extraction and CO2 sequestration rates in a four-year field trial in Southern Italy of two arboreal species (willow and poplar). The results show that, once established in the study area, willow extracted more Cd and Cu and less Pb than poplar. The two species demonstrated the same average Ni and Zn extraction rates. Greater biomass yields in poplar suggest that this species was able to fix greater amounts of CO2 (28.7 Mg ha−1 yr−1) than willow (24.9 Mg ha−1 yr−1). We argue that the choice of the species to be used in phytoextraction should first be made considering the TE-specific affinity and phytoextraction rates. For TEs whose ex...
Environment Control in Biology, 2016
Salinity is one of the most severe factors that limits the yield of filed, because most of crops ... more Salinity is one of the most severe factors that limits the yield of filed, because most of crops employed in agriculture is salt sensitive. This losses in yield is mainly due to drought and high salinity of field and this situation will be worst with global climatic changes. In particular the toxicity of Na is due to its ability to inhibit enzyme function directly by binding to inhibitory sites or indirectly by displacing K from activation sites. Plants have evolved a wide range of mechanisms to adapt and mitigate this kind of abiotic stress. Here we reviewed sensing and signaling mechanisms of salt stress and the tolerance strategies in plants.
Planta, 2003
Gaseous transport through lenticels is widely accepted to be the main pathway for oxygen supply t... more Gaseous transport through lenticels is widely accepted to be the main pathway for oxygen supply to the parenchymatous tissues of the wood. Circumstantial evidence exists that the oxygen required for respiration by these living cells can be obtained from the transpiration stream. However, there has been no functional confirmation of this role. To address this problem and to quantify the contribution of the different pathways to the oxygen supply of the sapwood, we have developed a three-electrode miniaturized oxygen-selective sensor to be implanted into the sapwood for long-term determination of the oxygen concentration. In spring, during the active growing season, the oxygen concentration of the sapwood of young olive (Olea europaea L.) trees changed from 80-90 micromol O(2) l(-1) around midday to 20-30 micromol O(2) l(-1) in the night. These concentrations correspond to a deficit of oxygen for the sapwood between 65-70% and 88-90% of an aqueous solution saturated with air. In the d...
Tree Physiology, 1999
Electrical impedance parameters were measured in shoots and leaves of Olea europaea L. for 18 mon... more Electrical impedance parameters were measured in shoots and leaves of Olea europaea L. for 18 months to determine seasonal variations in intracellular and extracellular resistances and in the state of membranes; these factors were related to rooting ability. Double-and single-DCE (ZARC) models were used as equivalent circuits for shoots and leaves, respectively. Seasonal variations were observed in all of the impedance parameters measured. Intracellular resistance of the shoots increased during the winter resting period, whereas intracellular resistance of the leaves decreased. Relaxation times for both leaves and shoots decreased during the winter. Close relationships were found between rooting ability and intracellular and extracellular resistances and relaxation times of shoots and leaves.
Plant, Cell & Environment, 2000
Plant, Cell & Environment, 2011
This work investigates the role of cytosolic Na + exclusion in roots as a means of salinity toler... more This work investigates the role of cytosolic Na + exclusion in roots as a means of salinity tolerance in wheat, and offers in planta methods for the functional assessment of major transporters contributing to this trait. An electrophysiological protocol was developed to quantify the activity of plasma membrane Na + efflux systems in roots, using the microelectrode ion flux estimation (MIFE) technique. We show that active efflux of Na + from wheat root epidermal cells is mediated by a SOS1-like homolog, energized by the plasma membrane H +-ATPase. SOS1-like efflux activity was highest in Kharchia 65, a salt-tolerant bread wheat cultivar. Kharchia 65 also had an enhanced ability to sequester large quantities of Na + into the vacuoles of root cells, as revealed by confocal microscopy using Sodium Green. These findings were consistent with the highest level of expression of both SOS1 and NHX1 transcripts in plant roots in this variety. In the sensitive wheat varieties, a greater proportion of Na + was located in the root cell cytosol. Overall, our findings suggest a critical role of cytosolic Na + exclusion for salinity tolerance in wheat and offer convenient protocols to quantify the contribution of the major transporters conferring this trait, to screen plants for salinity tolerance.
Plant and Cell Physiology, 2010
Polyamine (PA) levels in plants increase considerably under saline conditions. Because such an in... more Polyamine (PA) levels in plants increase considerably under saline conditions. Because such an increase is believed to be benefi cial for stress resistance, exogenous application of PAs has often been advocated as a means of ameliorating the detrimental effects of salinity. Results, however, are rather controversial, ranging from a signifi cant amelioration to being ineffective or even toxic. The reasons for this controversy remain elusive. The ability of a root to retain K + in the presence of NaCl was used as a physiological indicator to evaluate the ameliorative effects of PA. Pre-treatment with 1 mM Spm 4 + (spermine), Spd 3 + (spermidine) or Put 2 + (putrescine) prevented salt-induced K + leak only in the mature root zone of hydroponically grown maize and Arabidopsis. In contrast, in the distal elongation root zone, PA pre-treatment resulted in an even larger NaCl-induced K + effl ux, with the effect ranging from Spm 4 + > Spd 3 + = Put 2 +. A similar sequence has been also reported for H + pump inhibition, measured for both root zones. It appears that PAs affect cell membrane transporters in a highly specifi c way, with a relatively narrow 'window' in which amelioration is observed. We suggest that the ameliorative affect of PAs is the result of a complex combination of factors which might potentially include PA transport and accumulation in the cell cytosol, their metabolization and the functional expression of the specifi c target proteins or signaling elements.
Plant and Cell Physiology, 2006
The effect of anoxia on the energy economy of root cells was studied by measuring heat production... more The effect of anoxia on the energy economy of root cells was studied by measuring heat production, ethanol and ATP production, K + fluxes and electrical activity in two Vitis species, V. riparia and V. rupestris, that differ in their tolerance to anoxia. Anoxia triggered a marked decrease of metabolic activity (measured by microcalorimetry) and of ATP levels in both species. In V. riparia after the first 2 h of anoxia, the decrease in the rate of heat production was not associated with a further significant decrease in ATP content, whereas in V. rupestris the ATP level continued to decrease until very low values were reached. The concomitant increase in the rate of ethanol production did not compensate for the decreased aerobic ATP supply. In V. rupestris, anoxia typically led to energy deficit and ATP imbalance, together with the subsequent disruption of ion homeostasis and cell death. In V. riparia, the strong decrease in K + membrane permeability together with the fast down-regulation of the electrical signals allowed the cells to avoid severe ion imbalances during prolonged anoxic episodes.
Plant and Cell Physiology, 2011
The effect of a hypoxic pre-treatment (HPT) on improving tolerance to prolonged anoxia conditions... more The effect of a hypoxic pre-treatment (HPT) on improving tolerance to prolonged anoxia conditions in two contrasting Vitis species (V. riparia, anoxia tolerant; V. rupestris, anoxia sensitive) was evaluated. The energy economy of root cells was studied by measuring heat production, the activity of pyruvate decarboxylase (PDC) and alcohol dehdrogenase (ADH), ethanol and ATP production, and K + fluxes. The results showed that HPT is an effective tool in order to maintain a sustainable metabolic performance in both the species under anoxia conditions, especially in sensitive species such as V. rupestris. Our results showed that the improved tolerance was mainly driven by: (i) an enhanced activity of key enzymes in alcohol fermentation (ADC and PDC); (ii) the capability to maintain a higher level of respiration, evidenced by a lesser decrease in heat development and ATP production; and (iii) the maintenance of a better ion homeostasis (highlighted by measurement of K + fluxes) and K + channel functionality.
Journal of Solid State Electrochemistry, 2000
The electrochemical behaviour of a Cu/CuSe electrode was studied in order to de®ne its selectivit... more The electrochemical behaviour of a Cu/CuSe electrode was studied in order to de®ne its selectivity towards cupric ions, Nerstian response, limit of detection and response time. The chalcogenide electrode was prepared by cathodic deposition of Se and subsequent formation of a thin layer of CuSe on a copper substrate. A Cu/CuSe microelectrode was prepared using copper wire 75 lm in diameter. The dimensions and response time (<0.5 s) allowed use of this electrode in the``vibrating probe method'' with the aim of measuring net in¯uxes as well as euxes of copper(II) ions in Olea europaea roots. The electrode potential was measured along the root at a distance of 5 lm from the surface for 5 s, and then again for 5 s at a distance of 55 lm, moving the microelectrode with respect to the root surface by steps with a frequency of 0.1 Hz. The potentials measured at the two extremes of vibration were then converted to copper(II) concentrations. Substitution of these values in Fick's law yields the¯ux, assuming the diusion constant D for copper ions in aqueous solutions. The results enabled us to detect copper(II)¯uxes as small as 0.05 pmol cm)2 s)1. Copper(II) in¯ux showed marked spatial and temporal features: it was highest at about 1.5 mm from the root apex and exhibited an oscillatory pattern in time. Key words Copper selenide á Copper(II) uptake á Microelectrode á Olea europaea á Vibrating probe
Journal of Experimental Botany, 2011
Mechanical stimulation of trigger hairs on the adaxial surface of the trap of Dionaea muscipula l... more Mechanical stimulation of trigger hairs on the adaxial surface of the trap of Dionaea muscipula leads to the generation of action potentials and to rapid leaf movement. After rapid closure secures the prey, the struggle against the trigger hairs results in generation of further action potentials which inhibit photosynthesis. A detailed analysis of chlorophyll a fluorescence kinetics and gas exchange measurements in response to generation of action potentials in irritated D. muscipula traps was used to determine the 'site effect' of the electrical signal-induced inhibition of photosynthesis. Irritation of trigger hairs and subsequent generation of action potentials resulted in a decrease in the effective photochemical quantum yield of photosystem II (F PSII) and the rate of net photosynthesis (A N). During the first seconds of irritation, increased excitation pressure in photosystem II (PSII) was the major contributor to the decreased F PSII. Within ;1 min, non-photochemical quenching (NPQ) released the excitation pressure at PSII. Measurements of the fast chlorophyll a fluorescence transient (O-J-I-P) revealed a direct impact of action potentials on the charge separation-recombination reactions in PSII, although the effect seems to be small rather than substantial. All the data presented here indicate that the main primary target of the electrical signalinduced inhibition of photosynthesis is the dark reaction, whereas the inhibition of electron transport is only a consequence of reduced carboxylation efficiency. In addition, the study also provides valuable data confirming the hypothesis that chlorophyll a fluorescence is under electrochemical control.
Journal of Experimental Botany, 2010
Proteins and traces of polysaccharide are the only polymeric colloids consistently transported in... more Proteins and traces of polysaccharide are the only polymeric colloids consistently transported in the xylem sap of plants. The hypothesis that such proteins could have physical inhibitory effects on xylem water transport was investigated. Ovalbumin, with a molecular weight of 45 kDa and a molecular diameter of 5.4 nm, is an inert, watersoluble protein that is midway along the size range of endogenous xylem sap proteins. Solutions of ovalbumin conjugated to a fluorescent marker and supplied to transpiring shoot explants of tobacco (Nicotiana tabacum L.) and olive (Olea europaea L.) were shown by confocal laser scanning microscopy to accumulate specifically at wallbased pit membranes that connect neighbouring xylem conduits. In addition, pressure-induced perfusion of microfiltered ovalbumin solutions, at concentrations similar to those of endogenous xylem sap proteins, through the xylem of tobacco stem or olive twig segments resulted in the retention of c. 40% of the ovalbumin and reductions in the axial hydraulic conductance of the xylem. Smaller molecules such as Texas Red 3000 (MW 3 kDa) and Alexafluor 488-cadaverin conjugates (MW 0.64 kDa) did not show similar characteristics. The partial reduction in xylem hydraulic conductance appeared to be related to the accumulation of ovalbumin at xylem pit membranes and the consequent fouling of trans-membrane water-conducting pores with smaller diameters than those of the ovalbumin molecules. Potential implications of these novel findings for whole-plant water relations are considered.
Journal of Experimental Botany, 2005
Although oscillations in membrane-transport activity are ubiquitous in plants, the ionic mechanis... more Although oscillations in membrane-transport activity are ubiquitous in plants, the ionic mechanisms of ultradian oscillations in plant cells remain largely unknown, despite much phenomenological data. The physiological role of such oscillations is also the subject of much speculation. Over the last decade, much experimental evidence showing oscillations in net ion fluxes across the plasma membrane of plant cells has been accumulated using the non-invasive MIFE technique. In this study, a recently proposed feedback-controlled oscillatory model was used. The model adequately describes the observed ion flux oscillations within the minute range of periods and predicts: (i) strong dependence of the period of oscillations on the rate constants for the H 1 pump; (ii) a substantial phase shift between oscillations in net H 1 and K 1 fluxes; (iii) cessation of oscillations when H 1 pump activity is suppressed; (iv) the existence of some 'window' of external temperatures and ionic concentrations, where nondamped oscillations are observed: outside this range, even small changes in external parameters lead to progressive damping and aperiodic behaviour; (v) frequency encoding of environmental information by oscillatory patterns; and (vi) strong dependence of oscillatory characteristics on cell size. All these predictions were successfully confirmed by direct experimental observations, when net ion fluxes were measured from root and leaf tissues of various plant species, or from single cells. Because oscillatory behaviour is inherent in feedback control systems having phase shifts, it is argued from this model that suitable conditions will allow oscillations in any cell or tissue. The possible physiological role of such oscillations is discussed in the context of plant adaptive responses to salinity, temperature, osmotic, hypoxia, and pH stresses.
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Papers by Stefano Mancuso