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The Crassulacean Acid Metabolism (CAM) is a photosynthetic pathway typical of species of water-limited environments. In facultative species, CAM may be induced by different factors, water stress being the major. This work aimed to study metabolic and anatomical changes in young and mature leaves of Portulacaria afra (L.) Jacq. under progressive water stress and recovery. Young and mature leaves were selected for measurements of titratable acidity, chlorophyll a fluorescence, functional leaf characteristics, and morphological and cytological traits. As water stress increased, leaf water content, titratable acidity and maximum PSII photochemical efficiency (Fv/Fm) decreased in both young and mature leaves compared to control until a minimum value after 60 days. In contrast specific leaf area (SLA) raised during the stress. Mature leaves showed an higher water loss and a lower leaf dry matter content (LDMC) compared to young leaves. Microscopy analyses showed that the severe morpho-anatomical changes due to water deficit were reversible in both leaf types, since plasmolysis was not grave. After rewatering, a recovery of all parameters was observed in both young and mature leaves. Our data suggest that severe water stress induced a CAM-idling metabolism in both kinds of leaves. The full recovery of Fv/Fm at the end of rewatering indicated that P. afra is able to overcome the water stress and that the observed metabolic and cytological modification represent a strategy to face the stress period.

Climate change is intensifying the need to improve the use efficiency of farm resources and to increase crop yield and quality, especially in high profitability crops as grapevine. The achievement of these challenges requires the realization of a continuous crop monitoring in the field to identify and forecast possible anomalies in plant growth and health status due to short- and long-term environmental constrictions (e.g. climate change). Several indicators are currently used to evaluate plant growth, based on in situ data collection or remote sensing. In this study, we propose a multiscale approach to assess and interpret plant growth indicators in vineyard systems. We not only monitor plant growth and eco-physiology in-vivo during cultivation, but also reconstruct past eco-physiological behavior by transferring the approach of dendro-sciences, typical of the forest science domain, to viticulture. More specifically, we extract anatomical and stable isotope traits (linked with hydraulic and resource efficiency parameters) from tree-ring series to evaluate plant plasticity to past fluctuations in environmental conditions and to changes in the vineyard management. We also check whether the reconstructed eco-physiological behavior corresponds with the indexes obtained from the retrospective analysis of space-borne and UAVs data.

In many crops, including grapevine, the distribution of reflecting dust on foliage is a practice potentially leading to the mitigation of environmental stresses such as excessive light and limited water supply. This study aimed to evaluate whether the presence of dust on the leaves may affect PSII photochemical efficiency and gas-exchange measurements, thus leading to biased results. The study was conducted in a winery located at Benevento (Italy) on Vitis vinifera L. subsp. vinifera ‘Falanghina’ where the application of basalt dust was tested on the canopy to alleviate the effects of water stress. The results showed that there is no difference in PSII photochemistry or gas-exchange parameters measured in the presence of dust or after cleaning the leaves. Therefore, we conclude there is no need to remove dust from leaves before performing the ecophysiological investigations, thus fastening and simplifying the data collection.

The coordination of leaf hydraulic-related traits with leaf size is influenced by environmental conditions and especially by VPD. Water and gas flows are guided by leaf anatomical and physiological traits, whose plasticity is crucial for plants to face environmental changes. Only a few studies have analysed how variations in VPD levels influence stomatal and vein development and their correlation with leaf size, reporting contrasting results. Thus, we applied microscopy techniques to evaluate the effect of low and high VPDs on the development of stomata and veins, also analysing leaf functional traits. We hypothesized that leaves under high VPD with a modified balance between veins and stomata face higher transpiration. We also explored the variability of stomata and vein density across the leaf lamina. From the results, it was evident that under both VPDs, plants maintained a coordinated development of stomata and veins, with a higher density at low VPD. Moreover, more stomata but fewer veins developed in the parts of the lettuce head exposed to light, suggesting that their differentiation during leaf expansion is strictly dependent on the microclimatic conditions. Knowing the plasticity of hydraulic-related morpho-functional traits and its intra-leaf variability is timely for their impact on water and gas fluxes, thus helping to evaluate the impact of environmental-driven anatomical variations on productivity of natural ecosystems and crops, in a climate change scenario.

The increasing irregularity in precipitation patterns and frequency of extreme drought events in the Mediterranean area is challenging the sustainability of grapevine production, especially in some areas of southern Italy. Here, being the grapevine mostly rainfed-cultivated, there is a strong demand for cultivation techniques aiming to improve water use efficiency and water stress tolerance.Pruning techniques and training system can have an effect on the hydraulic architecture of vines, thus on their hydraulic behavior that is strictly coordinated with photosynthetic efficiency and ultimately contribute to determine yield and grape quality.In this study, we aimed to evaluate whether and to what extent a change in pruning technique can influence the efficiency and safety of water flow in vines. In order to pursue this objective, we combined the dendro-sciences approach, analysing tree-ring width and anatomical features of vines subjected to an abrupt change in the pruning technique. The study was conducted within the GREASE project, funded by the Campania Region through the Rural Development Programme 2014-2020, within the framework of the optimization of agricultural practices for improving grapevine resources-use efficiency for the sustainable management of vineyards.The study was conducted in a vineyard of Vitis vinifera L. subsp. vinifera ‘Greco’ (Feudi di San Gregorio farm) located in southern Italy (Avellino) at a site where the pruning technique was changed in 2004 following the method by Simonit & Sirch (Simonit 2014 Manuale di potatura della vite Ed IA; Sun et al 2008 Am J Bot 95:1498-1505). This method applies pruning cuts oriented in a way to drive vine natural tendency in the branching, to reduce injuries stress, in order to modulate the hydraulic pathway to reduce resistances to flow. Wood cores were extracted by the vines trunk, tree-rings were dated and widths were measured according to dendro-chronological techniques using WinDENDRO software. Then the cores were subjected to thin sectioning to obtain tree-ring series that were analysed through microscopy and subjected to digital image analysis. Wood anatomical traits, linked with hydraulic conductivity and vulnerability, were quantified in each year. The tree-ring series were then annually separated and d13C was measured in each year, in order to obtain information on intrinsic water use efficiency. The overall wood anatomical and stable isotope parameters were integrated to reconstruct and interpret past eco-physiological vine behaviour in response to the change in pruning technique also taking into account the inter-annual environmental variability.The analysis of wood anatomical functional traits linked with carbon stable isotopes of grapevine tree-ring series confirmed that vineyard management technique can severely affect the vine water use, thus affecting plant growth, productivity and ultimately plant ability to adapt to changing environmental conditions.All these interactions and their effects on water use should be taken into account when designing management practices in vineyards for sustainable production.

Mediterranean trees and shrubs form intra-annual density fluctuations (IADFs) in tree rings as a sign of their plasticity in wood formation in response to intraseasonal variations of environmental conditions. Different species show a different aptitude to form IADFs, due to their diverse ability to cope with climate stressors, since the occurrence of IADFs may affect plant hydraulics. Dendroecology and quantitative wood anatomy were used to characterise IADFs in Pinus pinea and Arbutus unedo co-occurring at a Mediterranean site in Italy. The relations between climate parameters (i.e. temperature and precipitation) and intra-annual tree-ring traits (i. e. IADF frequency and conduit size) were analysed to highlight the main triggers for IADF formation and their functional role.Data showed that both species are characterised by a high plastic response to climate and formed a high frequency of L-IADFs (occurrence of earlywoodlike conduits in latewood). The two species, although forming the same type of IADFs, showed different sensitivity to environmental factors. Pinus pinea showed a high dependence of tracheid size on temperature, while Arbutus unedo was more sensitive to precipitation in spring and autumn. Arbutus unedo promptly developed more than one IADF per year in response to rainfall events following drought periods.The overall results were useful to compare the aptitude of the two species in forming IADFs and to highlight the factors priming their formation. This is useful to understand wood growth reactions to environmental drivers and to evaluate the adaptive capabilities in these two species, and thus to predict forest reactions after climate changes.

Agroforestry applications in viticulture are considered a promising strategy to improve vine water status by mitigating the threats of increasing drought due to climate change. The analysis of δ¹³C is often used in viticulture to understand vine water use. In this study, the analysis of δ¹³C was performed on the must of Falanghina grapevines growing in different pedoclimatic conditions. The aim was to compare the results obtained by the application of two different methodologies, using the whole must or extracted sugars as the matrix. The results showed that the δ¹³C values obtained by applying the two methodologies were comparable in all analyzed vineyards independently from the pedoclimatic conditions. Indeed, the proposed method of extraction of the δ¹³C on the must as a whole can be both cost- and time-saving for the analysis. This is valuable, considering that the δ¹³C of must is becoming more and more used as indicator of vines’ water use. Therefore, the possibility to utilize a simplified method of extraction would enhance the application of the δ¹³C at a larger scale to evaluate vine adaptation in the context of climate-change-driven increases in drought.

Mixed forests of Quercus ilex L. and Pinus pinea L. are widely found throughout the Mediterranean Basin, being representative of two co-existing functional types: evergreen-sclerophyllous drought-resistant species and Mediterranean-adapted drought-avoidant conifers. Their contrasting physiological strategies to cope with water deficit influence all the processes regulating their growth such as wood formation, leading to peculiar tree-ring anatomical features such as intra-annual density fluctuations (IADFs). Intra-annual density fluctuations are abrupt changes in wood anatomical traits within a tree ring, appearing as latewood-like cells within earlywood or earlywood-like cells within latewood, and are frequently found in Mediterranean species as a response to seasonal climate changes. In this study, we characterized the anatomical traits and composition of carbon and oxygen stable isotopes in IADFs occurring in tree rings of Q. ilex and P. pinea trees co-existing at a same site in Southern Italy, in order to link their xylem hydraulic properties with the related physiological mechanisms. The relationships between IADF occurrence and seasonal mean temperature and total precipitation were investigated, with the aim of assessing whether they can be used as indicators of species-specific responses to intra-annual climate fluctuations. Results show that IADF period of formation is during autumn months for both species. The influence of climate on IADF occurrence was found to be an indicator of species-specific response to climate: an increased stomatal conductance associated to the formation of a wood safer against embolism was found in Q. ilex, while a tighter stomatal control associated to a more efficient wood with regard to hydraulic conductivity occurred in P. pinea. Moreover, the assessment of the influence of climate on IADF occurrence indicates that, with rising temperatures, Q. ilex would form fewer IADFs compared with P. pinea. Other study cases are desirable to assess the suggested forecasts and to link the plasticity of the species to form IADFs with their effective adaptive capability to compete for resources, and to explain how it may influence future population development.

Projected changes in drought occurrence in the Mediterranean region are raising concerns about the adaptive capability of rainfed crops, such as grapevine, to in- creasing aridity. Cultivation management, especially the techniques in uencing the hydraulic pathway, can play a role in plant adaptation to drought for the con- sequent changes in wood anatomical functional traits. The aim of this study was to assess the effect of grafting on wood anatomy in tree-ring series of Vitis vini- fera L. ‘Piedirosso’ grapevine cultivated in a volcanic area in Southern Italy. Tree- ring anatomy was analysed in vines grown on their own roots or grafted onto 420A rootstock. results showed that grafted vines had a higher occurrence of wood traits linked with safety of water transport if compared with non-grafted vines. Grafting induced the formation of tree rings with higher incidence of latewood also characterised by narrower and more frequent vessels if compared with non-grafted vines. This study suggested a different regulation of water ow in the grafted and non-grafted vines. Such ndings support the analysis of wood anatomy as a tool to drive decisions linked with plant cultivation management. In this speci c case, our results encourage to further explore the change from a traditional cultivation with own-rooted grapevines towards grafted models inducing better xylem adaptation to increasing drought. Projected changes in drought occurrence in the Mediterranean region are raising concerns about the adaptive capability of rainfed crops, such as grapevine, to in-creasing aridity. Cultivation management, especially the techniques influencing the hydraulic pathway, can play a role in plant adaptation to drought for the con-sequent changes in wood anatomical functional traits. The aim of this study was to assess the effect of grafting on wood anatomy in tree-ring series of Vitis vinifera L. Piedirosso' grapevine cultivated in a volcanic area in Southern Italy. Tree-ring anatomy was analysed in vines grown on their own roots or grafted onto 420A rootstock. Results showed that grafted vines had a higher occurrence of wood traits linked with safety of water transport if compared with non-grafted vines. Grafting induced the formation of tree rings with higher incidence of latewood also characterised by narrower and more frequent vessels if compared with non-grafted vines. This study suggested a different regulation of water flow in the grafted and non-grafted vines. Such findings support the analysis of wood anatomy as a tool to drive decisions linked with plant cultivation management. In this specific case, our results encourage to further explore the change from a traditional cultivation with own-rooted grapevines towards grafted models inducing better xylem adaptation to increasing drought.

The aim of this work was to assess the possible coordination mechanisms between leaf functional anatomical traits and physiological acclimation of potted Callistemon citrinus plants when subjected to two saline iso-osmotic solutions using NaCl or CaCl2. Digital image analysis was applied to quantify anatomical parameters with a specific focus on the occurrence of signs of structural damage as well as on alterations, such as the occurrence of shrunk tissues and accumulation of phenolic compounds. Morpho-anatomical analyses were accompanied by measurements of leaf gas exchange and chlorophyll fluorescence emission. Results showed that C. citrinus plants, when irrigated with the CaCl2 solution, induced a leaf morpho-anatomical structure which did not allow the maintenance of high photosynthetic performance under such conditions, compared to both controls and plants treated with the iso-osmotic solution of NaCl. Data collected seem to suggest a close relationship between anatomical traits and eco-physiological strategies in maintaining the photosynthetic efficiency under saline stress conditions and highlight the fundamental role of leaf anatomy in imposing the limits of plant physiology.

Callistemon citrinus and Viburnum lucidum are appreciated and widespread ornamental shrubs for their abundant flowering and/or brilliant foliage. The intrinsic tolerance to drought/salinity supports their use in urban areas and in xeriscaping. Despite adaptive responses of these ornamental species to sodium chloride (NaCl) have been extensively explored, little is known on the effects of other salt solution, yet iso-osmotic, on their growth, mineral composition and metabolism. The present research was aimed to assess responses at the biochemical, physiological and anatomical levels to iso-osmotic salt solutions of NaCl and CaCl2 to discriminate the effects of osmotic stress and ion toxicity. The two ornamental species developed different salt-tolerance mechanisms depending on the salinity sources. The growth parameters and biomass production decreased under salinization in both ornamental species, independently of the type of salt, with a detrimental effect of CaCl2 on C. citrinus. The adaptive mechanisms adopted by the two ornamental species to counteract the NaCl salinity were similar, and the decline in growth was mostly related to stomatal limitations of net CO2 assimilation rate, together with the reduction in leaf chlorophyll content (SPAD index). The stronger reduction of C. citrinus growth compared to V. lucidum, was due to an exacerbated reduction in net photosynthetic rate, driven by both stomatal and non stomatal limitations. In similar conditions, V. lucidum exhibited other additional adaptive response, such as modification in leaf functional anatomical traits, mostly related to the reduction in the stomata size allowing plants a better control of stomata opening than in C. citrinus. However, C. citrinus plants displayed an increased ability to retain higher Cl- levels in leaves than in roots under CaCl2 salinity compared to V. lucidum, thus, indicating a further attempt to counteract chloride toxicity through an increased vacuolar compartmentalization and to take advantages of them as chip osmotica.

Intra-annual density fluctuations (IADFs) in tree rings are generally considered structural anomalies caused by deviations from the “normal course” of xylogenesis during the growing season. This definition is based on the bias that, under “normal conditions”, cambial activity stops once a year. Each tree ring can thus be dated to one calendar year, which is one of the principles of dendrochronology. The formation of IADFs can be triggered directly by environmental changes, especially in precipitation and temperature, that affect cambial activity and cell differentiation. It can also be the result of limited photosynthesis, due to defoliation induced by biotic or abiotic constraints. Often indicated with alternative terms, IADFs were first described in the 1930s, and recently reported for many trees and shrubs from different ecosystems throughout the world, particularly for Mediterranean species. Different types of IADFs have been detected; their formation and structural properties depend on many factors including tree genotype, age, size, rooting depth, habitat, soil, climate, photosynthetic activity, and allocation strategies. Whether IADFs affect the adaptive capability of plants remains, however, unclear. We provide an overview of the main anatomical features of IADFs and their occurrence in tree rings from various environments and climatic regimes. We propose a simplified way of classifying them and discuss the hypotheses about their functional role and the factors triggering their formation. To understand the ecological role of IADFs better, we recommend a multidisciplinary approach, involving wood anatomy, dendroecology, and stable isotopes, which has already been applied for Mediterranean species. We conclude by considering that IADFs appear to be the “rule” rather than “anomalies” in some ecosystems where they help plants cope with fluctuating environmental conditions. Moreover, their anatomical structure represents a valuable proxy of past climatic conditions at a sub-seasonal resolution and may be relevant to adapt hydraulic functioning of living trees to changing climatic conditions.

Proximal sensors in controlled environment agriculture (CEA) are used to monitor plant growth, yield, and water consumption with non-destructive technologies. Rapid and continuous monitoring of environmental and crop parameters may be used to develop mathematical models to predict crop response to microclimatic changes. Here, we applied the energy cascade model (MEC) on green- and red-leaf butterhead lettuce (Lactuca sativa L. var. capitata). We tooled up the model to describe the changing leaf functional efficiency during the growing period. We validated the model on an independent dataset with two different vapor pressure deficit (VPD) levels, corresponding to nominal (low VPD) and off-nominal (high VPD) conditions. Under low VPD, the modified model accurately predicted the transpiration rate (RMSE = 0.10 Lm&minus, 2), edible biomass (RMSE = 6.87 g m&minus, 2), net-photosynthesis (rBIAS = 34%), and stomatal conductance (rBIAS = 39%). Under high VPD, the model overestimated photosynthesis and stomatal conductance (rBIAS = 76&ndash, 68%). This inconsistency is likely due to the empirical nature of the original model, which was designed for nominal conditions. Here, applications of the modified model are discussed, and possible improvements are suggested based on plant morpho-physiological changes occurring in sub-optimal scenarios.

In this century, one of the main objectives of agriculture is sustainability addressed to achieve food security, based on the improvement of use efficiency of farm resources, the increasing of crop yield and quality, under climate change conditions. The optimization of farm resources, as well as the control of soil degradation processes (e.g., soil erosion), can be realized through crop monitoring in the field, aiming to manage the local spatial variability (time and space) with a high resolution. In the case of high profitability crops, as the case of vineyards for high-quality wines, the capability to manage and follow spatial behavior of plants during the season represents an opportunity to improve farmer incomes and preserve the environmental health. However, any field monitoring represents an additional cost for the farmer, which slows down the objective of a diffuse sustainable agriculture. Satellite multispectral images have been widely used for production management in large areas. However, their observation is limited by the pre-defined and fixed scale with relatively coarse spatial resolution, resulting in limitations in their application. In this paper, encouraged by recent achievements in convolutional neural network (CNN), a multiscale full-connected CNN is constructed for the pan-sharpening of Sentinel-2A images by UAV images. The reconstructed data are validated by independent multispectral UAV images and in-situ spectral measurements. The reconstructed Sentinel-2A images provide a temporal evaluation of plant responses using selected vegetation indices. The proposed methodology has been tested on plant measurements taken either in-vivo and through the retrospective reconstruction of the eco-physiological vine behavior, by the evaluation of water conductivity and water use efficiency indexes from anatomical and isotopic traits recorded in vine trunk wood. In this study, the use of such a methodology able to combine the pro and cons of space-borne and UAVs data to evaluate plant responses, with high spatial and temporal resolution, has been applied in a vineyard of southern Italy by analyzing the period from 2015 to 2018. The obtained results have shown a good correspondence between the vegetation indexes obtained from reconstructed Sentinel-2A data and plant hydraulic traits obtained from tree-ring based retrospective reconstruction of vine eco-physiological behavior.

Intra-annual density fluctuations (IADFs) are anomalies of tree rings where wood density is abruptly altered after sudden changes in environmental conditions. Their characterisation can provide information about the relationship between environmental factors and eco-physiological processes during tree growth. This paper reports about the variability of anatomical traits and stable carbon isotopic composition along tree rings as resulting from the application of two different methodological approaches: (a) the separation of each ring into different regions (earlywood, latewood and IADF) and the comparison of anatomical and isotopic parameters measured in those specific sectors and (b) the analysis of such features in continuum along ring width. Moreover, different parameters of vessels (i. e. ecd-equivalent circle diameter, elongation, sphericity and convexity of vessel lumen) were considered to identify those more appropriate for the representation of intra-annual anatomical variations. The analysis was conducted on Arbutus unedo L. growing on the Elba Island (Italy); tree rings of this species form IADFs with features clearly responsive to the environmental conditions experienced during plant growth. Results showed that the first approach, although more suitable to obtain data for subsequent statistical comparisons and for the calculation of correlations with environmental parameters, suffers from elements of subjectivity due to the size and position of the selected tree-ring regions. The in continuum method allows a clearer identification of the variation of tree-ring properties along ring width. Regarding anatomical parameters, shape indexes were not suitable indicators of intra-annual variability. The overall analysis suggested that using both methodologies in synergy helps to gain complete information and avoid misleading interpretations of IADFs in tree rings. © 2011 Springer-Verlag.

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Summary: Woody species in Mediterranean ecosystems form intra-annual density fluctuations (IADFs) in tree rings in response to changes in environmental conditions, especially water availability. Dendrochronology, quantitative wood anatomy and high-resolution isotopic analysis (using a laser ablation technique) were used to characterize IADFs in Arbutus unedo shrubs grown on two sites with different water availability on the island of Elba (Italy). Our findings show that IADF characterization can provide information about the relationship between environmental factors and tree growth at the seasonal level. At the more xeric site, IADFs mainly located in the early and middle parts of the annual ring, showed a decrease in vessel size and an increase in δ13C as a result of drought deficit. Opposite trends were found at the more mesic site, with IADFs located at the end of the ring and associated with a lower δ13C. Moreover, at the first site, IADFs are induced by drought deficit, while at the second site IADFs are linked with the regrowth in the last part of the growing season triggered by favourable wet conditions. This combined approach is a promising way for dating problematic wood samples and interpreting the phenomena that trigger the formation of IADFs in the Mediterranean environment. © The Authors (2010). Journal compilation © New Phytologist Trust (2010).

It is the current opinion that sustainable future in space is based on affordable initiatives. Reused rocket is a dream come true but, in addition to the drastic reduction of flight expenses, new efforts should reduce costs of experiments in Space. The use of refurbished hardware can be a valid but challenging solution for researchers that have to reach their scientific goals, accepting all technical constraints of hardware originally designed for satisfying requirements of a different experiment. In 2017, ASI (Agenzia Spaziale Italiana) promoted YiSS (Youth ISS Science), a call for educational and scientific experiments to be performed on ISS during the VITA (Vitality, Innovation, Technology and Ability) mission, with astronaut Paolo Nespoli. A requirement of the call was to select the Experiment Unit within a set of nine all of which were previously used for other experiments in microgravity. The EUs were designed, developed and flight-certified by Kayser Italia. Among the 13 projects submitted for the competition, MULTITROP (MULTITROPism: interaction of gravity, nutrient and water stimuli for root orientation in microgravity) was the winner. The project was ideated by scientists of the Department of Agricultural Sciences of the University of Naples Federico II, in collaboration with students from the University and a High School. In addition to the educational aims of enhancing young people's interest in Space biology, the experiment had a scientific goal in plant Space biology. It aimed to disentangle the role of gravity from the other two stimuli for root orientation: hydrotropism and chemotropism. ASI has funded and coordinated the programme, also providing access to the Space resources thanks to a bilateral agreement with NASA. MULTITROP was performed in a BIOKON container equipped with two Experiment Units previously flown for the YING (Yeast In No Gravity) experiment, supported by ESA (European Space Agency) in 2009. The hardware was refurbished and re-adapted by Kayser Italia to fulfil the new mission requirements. So far, pre-flight and in-flight phases have been successfully completed while the post-flight one is still in progress. Students enthusiastically took part in laboratory activities and dissemination events. One lesson learned was that to plan a new experiment with refurbished HW, scientists should evaluate not only the HW details but also the specific environmental conditions expected during the pre-flight and flight operations. Within the scenario of using refurbished HWs, the possibility to control common environmental parameters should be always ensured in order to limit biological constraints.