BG3.16

The role of forest biodiversity in supporting ecosystem functioning is remarked to be context-dependent, and changes in environmental conditions could alter the shape of biodiversity-ecosystem functioning (BEF) relationships. However few studies have explored the processes underlying shifts in BEF relationships along abiotic gradients, which limits our ability to predict how the BEF relationship will respond to the rapid future changes in environmental conditions caused by climate change. In this study, we sought to test (i) how a water limitation gradient shapes the functional composition and diversity of forests, (ii) how functional composition and diversity of trees relate to forest productivity, and (iii) if functional diversity is more strongly related to productivity in the Mediterranean or temperate climate. To address these points, we created a functional trait data set covering traits of most of the tree species within the Italian peninsula, using forest surveyed data sets from the National Forest Inventory. We found that functional composition varied with water limitation as tree communities tended to have more `conservative` resource strategies (e.g., low specific leaf area and high wood density) under increased water limitation. Functional diversity´s response was highly variable, however, increased water limitation has been found to enhance also functional diversity in the temperate domain. Biodiversity positively influenced forest productivity through a combination of mass ratio and niche complementary effects in Italian forests, but the relative importance of these effects is dependent on the functional trait and bioclimate considered. Niche complementary effects showed a more predominant effect on productivity in the Mediterranean compared to temperate forests. Overall, our results suggest that biodiversity plays an important role in driving forest productivity under more environmental stressed conditions by promoting beneficial interactions between species and complementarity in resources.

How to cite: Lammerant, R., Rita, A., Borghetti, M., and Muscarella, R.: The importance of functional diversity in forest productivity is driven by environmental stress in Italy, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8856, https://doi.org/10.5194/egusphere-egu22-8856, 2022.

Investigating the responses of plant anatomical traits of trees to drought-rewatering cycles helps us to understand their responses to climate change; however, such work has not been adequately reported. In this study, Ginkgo biloba L. saplings were subjected to moderate, severe, extreme and lethal drought conditions by withholding water according to PLCs (the percentage loss of hydraulic conductivity) and rewatering on a regular basis. Samples of phloem, cambium, and xylem were collected to quantify their cellular properties, including cambium and phloem cell vitality, xylem growth ring width, pit aspiration rates and pit membrane thickness, using light microscopy and transmission microscopy. The results showed that the mortality rate of G. biloba saplings reached 90% at approximately P₈₈ (xylem water potential inducing 88% loss of hydraulic conductivity). The onset of cambium and phloem cell mortality might be in accordance with that of xylem embolism. Close negative correlations between xylem water potential and PLC and between xylem water potential and cambium and phloem mortality suggested that xylem hydraulic traits are coupled with anatomical traits under declining xylem water potential. Cambium and phloem cell vitality as well as xylem growth ring width decreased significantly with increasing drought conditions. However, xylem pit membrane thickness, cambial zone width and cambial cell geometry were not affected by the drought-rewatering cycles. The tracheid radial diameter, inter-tracheid cell wall thickness and tracheid density decreased significantly during both drought conditions and rewatering conditions. In addition to hydraulic traits, cambium and phloem cell vitality can be used as anatomical traits to evaluate the mortality of G. biloba under drought. Future work is proposed to observe the dynamics of pit aspiration rates under drought-rewatering cycles in situ to deepen our understanding of the essential role of bordered pits in the “air seeding” mechanism.

Key words: cambium and phloem cell vitality, xylem vulnerability curves, xylem growth ring width, pit membrane thickness, pit aspiration rate, tree mortality, lethal water potential under drought

https://academic.oup.com/treephys/advance-article-abstract/doi/10.1093/treephys/tpab174/6485193

How to cite: Li, S.: Hydraulic traits are coupled with plant anatomical traits under drought-rewatering cycles in Ginkgo biloba L., EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1016, https://doi.org/10.5194/egusphere-egu22-1016, 2022.

Resin is a natural defensive substance produced by trees in response to injury and infection and is a sustainable and valuable non-timber forest product. Resin tapping is a traditional activity that besides increasing the economic profit of forest plantations, it provides ecosystem services and promotes the development of rural areas. However, the effect of resin tapping on tree growth remains elusive. Furthermore, there is evidence connecting resin production with climatic conditions, but tree-growth responses to climatic conditions and stand characteristics in resin-tapped and non-tapped trees remains unclear. Our aim is to understand if resin tapping affects tree growth, and how tree age, edaphoclimatic conditions and stand characteristics interplay. A dendrochronological study was conducted in six Pinus pinaster stands across a latitudinal gradient from North to the Centre of Portugal. The stands that had been resin-tapped for 5 to 7 years, presented different climate conditions and characteristics, i.e. different cambial ages. When tree-growth (tree ring-width; TRW) on tapped and untapped trunk sides was compared during the resin-extraction period, there was a slight enhancement of growth in the resin-tapped side of the youngest populations (<30 years) and no changes in older populations (>40 years). Annual resin-tapping impact (RTI), calculated as the ratio between TRW during resin harvesting years and the 5-year average TRW before tapping, was below (above) 1 in the younger (older) stands. Among other stand characteristics, RTI was negatively correlated with tree competition. Climatic conditions did not have a major influence on tree growth in response to resin tapping. In conclusion, the effect of resin extraction on growth is age dependent, with younger trees being more negatively affected. Our results seem to indicate that the co-production of resin and timber should be performed in pine populations older than 40 years.

How to cite: Moura, M., Campelo, F., Nabais, C., and García-Forner, N.: Resin harvesting’s effect on maritime pine growth varies with tree age, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1103, https://doi.org/10.5194/egusphere-egu22-1103, 2022.

Nowadays, about 50% of the global yield loss is due to climate change. Increasing Vapor Pressure Deficit (VPD) and drought are among the principal environmental stressors, affecting stomatal regulation and reducing plant photosynthesis and biomass accumulation. Recent studies have revealed that the extent of plant acclimation is closely related to the anatomical traits of the leaves, which change with environmental conditions. It is not yet clear how the interaction between these environmental factors affects plant morpho-physiological development and plant capacity of acclimation under changing conditions. To fill this gap, in this study we used a high-throughput phenotyping facility (at the IPK-Gatersleben, Germany) to grow two lettuce cultivars (Lactuca sativa L. var. capitata) with green and red leaves under different VPDs (low and high) and watering regimes (well-watered, WW, and low watered, LW regimes). Two trials were performed: the first trial was conducted at a VPD of 0.7 kPa (low VPD) and the second at 1.4 kPa (high VPD), both with WW and WD conditions. After 12 days of cultivation in the phenotyping chamber, the environmental conditions were switched, and plants were kept for 5 days at the opposite VPD to evaluate their acclimation ability. RGB imaging was applied to track changes in morphological parameters, near-infrared camera (NIR) was used to estimate plant-water relationships, and FLUO made it possible to evaluate changes in photosystem II reflecting optimal/stressful conditions. At the end of the experimental trials, the leaf samples were characterized in terms of stomatal and mesophyll traits by light microscopy. A specific focus was d­edicated to exploring how stomata regulation and water use efficiency affect carbon gain and biomass allocation in pre-acclimated lettuces to different environmental conditions (VPDs) and hence undergoing sudden changes in the VPD. To test the influence of the different independent factors: i) VPD, ii) cultivar (C), iii) water (W) on the dependent variables, a three-way analysis of variance (ANOVA) was performed. Additionally, correlation plots and the principal component analysis were performed to explore correlations between morpho-anatomical and phenotypic data points. The results showed that WW plants at low VPD developed a morpho-anatomical structure in terms of mesophyll organization, stomatal and vein density which more efficiently guided acclimation to sudden changes in the environmental conditions and which was not detected by image-based phenotyping alone. Therefore, we emphasized the need to complement high-throughput phenotyping with the analysis of anatomical traits to unravel the mechanisms of crop acclimation under sudden fluctuation in environmental conditions due to climate change. Such an approach can help improving knowledge on how stomatal regulation and carbon allocation affect productivity in warmer areas and drier climates, with high impact also for the design of cultivation protocols for sustainable indoor farming.

How to cite: Amitrano, C., Junker, A., D'agostino, N., De Pascale, S., and De Micco, V.: Combination of high-throughput phenotyping with plant anatomical trait measurements to understand lettuce morpho-physiological acclimation under changing VPDs and watering regimes., EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2548, https://doi.org/10.5194/egusphere-egu22-2548, 2022.

Space exploration always has fascinated scientists, and in the last decades, the interest in this goal has increased exponentially. However, the realization of crewed space exploration missions or the permanence of human settlements on orbital stations or planetary habitats requires Life Support Systems (LSS) based on the interaction among abiotic and biotic elements, resembling terrestrial ecosystems. As on Earth, plants in Space would be involved in air regeneration through photosynthesis, water recovery, waste processing and food production, providing the astronauts with renewed resources and fresh food.

The extraterrestrial environment may be considered one the most extreme for organisms’ survival because of several Space factors constraining biological life (e.g., altered gravity, fluid-dynamic and microgravity interaction, modified pressure, temperature). Among them, ionizing radiation influences severely plant growth and metabolic processes.  Our study explores the response of tomato (Solanum lycopersicum L. ‘Microtom’), one of most widely cultivated crops, to different doses of sparsely ionizing radiation (IR), with two main goals: 1) to evaluate the morpho-functional mechanisms conferring radioresistance to guarantee their ecological role in closed, controlled environments; 2) to assess the possibility to use IR as a “biostimulant” to produce plant-derived functional food richer in functional compounds.

Different doses of X-rays (0.3, 1, 10, 20, and 30 Gy, 6 MV energy), were delivered on dry seeds (DS) and germinated seeds (GS) and compared to not-irradiated controls, to define a dose-response curve and check possible negative/positive outcomes on seedlings. After the irradiation treatments, seeds/seedlings were transferred to a climatic chamber and cultivated under controlled environmental conditions of light, temperature, relative humidity and photoperiod. For our study, we adopted a multidisciplinary approach that merges anatomical analyses with measurements of photosynthetic efficiency and biochemical traits, including polyphenols and other antioxidant compounds linked with the nutritional value of derived food. The growth and photosynthetic performance of DS and GS plants were followed during the whole plant life cycle, while anatomical traits and fruit antioxidant properties were determined at full maturity of the specific organs.

The results showed that the outcomes of radiation are dose-specific and dependent on the irradiated target stage, being SS plants more high-performing in photosynthetic activity and antioxidant content in fruits than SGs. Furthermore, some doses of X-rays act as a booster of bioactive compounds in fruits of both SS and SG plants. The outcomes of this research will be helpful to optimize crop production in Space and controlled environment agriculture systems. Moreover, the fine analysis of the relations between anatomical, eco-physiological and biochemical traits will furnish valuable insights to understand mechanisms of plant acclimation to stress, useful to manage cultivation factors to improve resource use optimization in controlled environments cultivations on Earth in line with sustainable development goals.

How to cite: Arena, C., Vitale, E., Costanzo, G., De Francesco, S., Amitrano, C., Pugliese, M., Arrichiello, C., Ametrano, G., Muto, P., and De Micco, V.: A coin with two faces: understanding effects of ionizing radiation in space farming - the case of Solanum lycopersicum L. ‘Microtom’, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3097, https://doi.org/10.5194/egusphere-egu22-3097, 2022.

Koprowski et al. 2015 investigated the effect of N, P, K elements contained in wastes from the Forest Wastewater Treatment (FWT) zone, entering a forest area from a potato starch factory. It was found that the use of starch causes a reduction in the photosynthetic efficiency and growth of Scots pine. The study extends the tree ring analysis of Scots pine by cell wood anatomy. It was examined how cell parameters like cell wall thickness (CWT), lumen diameter (LD) and ring width (RW) responded to fertiliser supply in different years. Three sites were distinguished at the FWT zone. Site 1 and 2 were located in the FWT zone, whilst Site 3 was a control site situated outside this zone. Trees growing at Site 1 were fertilised, whilst trees growing at Site 2 were unfertilised despite being located within the FWT zone. The amount of water supplied and the concentration of elements varied over the years, which, in combination with the supply of fertiliser, clearly influenced the cellular structure of the growths, as was seen in the microscopic examination. For anatomical analyses, one of the most representative and highly correlated trees from each site was selected: site 1 - 0.78, site 2 - 0.74, site 3 - 0.77. The analysis was based on growth years 1961-2011. Preliminary climatic studies confirm a negligible effect of precipitation and temperature on observed variations in cell parameters at these sites. Thus the results obtained seem to depend mainly on fertilisation and water supply.

How to cite: Waszak, N., Campelo, F., Robertson, I., Puchałka, R., Boularbach, A., and Koprowski, M.: Effect of potato starch application on wood cell parameters of Scots pine (Pinus Sylvestris L.), EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4331, https://doi.org/10.5194/egusphere-egu22-4331, 2022.

The success of future long-term manned missions in Space is strictly related to the development and setup of sustainable closed artificial ecosystems, defined as Bioregenerative Life Support Systems (BLSSs). In these BLSSs, the cultivation of higher plants represents the core element, given its role in primary resources (e.g., oxygen, water) regeneration and in fresh food production, also helping to counteract the emergence of Space-induced diseases in astronauts. However, Space farming may be constrained by Space ionizing radiation for its influence on plant growth and biomass production, depending on radiation properties and plant intrinsic factors (e.g., type of radiation, dose, plant species, cultivar, developmental stage at the time of irradiation). 

This study aimed to evaluate the effects of the different types and doses of low and high-LET (Linear Energy Transfer) radiation on morpho-anatomical traits and antioxidant content of Brassica rapa L. subsp. sylvestris var. esculenta microgreens. Dry seeds were exposed to different doses (0-control, 0.3, 1, 10, 20, and 30 Gy) of X-rays (the reference Low-LET radiation) at Istituto Nazionale Tumori - IRCCS - Fondazione G. Pascale, and to two types of Heavy Ions, namely ¹²C and ⁵⁶Fe (to simulate the High-LET radiation) at different doses (0-control, 0.3, 1, 10, 20, and 25 Gy) at GSI Helmholtzzentrum für Schwerionenforschung GmbH. After the irradiation, seeds were sowed and microgreens were cultivated in a growth chamber under controlled environmental conditions, monitoring germination and survival, as well as growth performances. At the harvest, morpho-biometric traits, such as stem elongation, fresh and dry biomass, and total leaf area were measured. Leaf functional anatomical traits (e.g., lamina thickness, localization of phenolics, stomatal frequency) were quantified through light and epifluorescence microscopy and digital image analysis. The antioxidant charge of microgreens was evaluated considering antioxidant capacity, and polyphenols, chlorophylls, and carotenoid content. Results highlighted that the responses of microgreens, from irradiated seeds, were dose and radiation-type specific. This study furnished useful insights to evaluate plant radio-resistance at early stages of development, namely seedling establishment, that is a very critical phase in the plant life cycle. Gained information is useful to support the decision actions about the choice of suitable species to be cultivated in the BLSSs in Space and the definition of the shielding requirements for Space cultivation facilities.

Part of the results presented here is based on the experiment Bio_08_DeMicco, which was performed at the SIS18 at the GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany) in the frame of FAIR Phase-0.

How to cite: De Francesco, S., Amitrano, C., Costanzo, G., Vitale, E., Tinganelli, W., Durante, M., Pugliese, M., Arrichiello, C., Ametrano, G., Muto, P., De Micco, V., and Arena, C.: Different types of ionizing radiation induce morpho-anatomical and antioxidant responses in Brassica rapa L. microgreens, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5623, https://doi.org/10.5194/egusphere-egu22-5623, 2022.

Forests are known to play a key role in the ecosystem health. In fact, they provide a wide range of ecosystem services, such as carbon sequestration for climate change mitigation, nutrient cycle regulation, and biodiversity conservation. For these reasons, the reforestation of degraded sites is listed as a nature based solution. On the other hand, forests represent the main wood source available to meet global needs and could play a fundamental role in the transition of a traditional linear economy towards a circular economy. This implies an economy where raw materials and their value are employed as efficiently as possible, converting the under-valued forest residues into value-generating market forest waste use. In this context, the reforestation of exploited soils for soil requalification could offer the owners an economic yield beyond that by wood, also considering the valorisation of the abundant waste material (e.g. leaf material). To this purpose, and in order to avoid the impacting abandonment phenomenon, our reforestation approach innovatively aims at identifying a specific forest management type, capable of achieving these goals.

A mixed-species plantation in Central Italy was of our interest. It consists of three different associations: particular ancillary species, namely Alnus cordata, Elaeagnus umbellata (both N-fixing species), and Corylus avellana, are in association with valuable species, such as Populus alba and Juglans regia planted on a former agricultural land. The relationship between the chemical and biological topsoil (0-10 cm) properties was evaluated, as well as the leaf antiradical capability of both the valuable species, observing that they vary among different intercropping systems. The lignin and cellulose content, both in soil and leaves, was assessed, along with soil total organic carbon, soil total nitrogen, soil fluorescein diacetate hydrolase activity. Furthermore, Populus alba and Juglans regia leaves were investigated for their phenol content, and for their anti-radical activity by means of DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS [2, 2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid)] assays. Data acquired highlight that the leaf material represents an important source of bioactive compounds and that the different associations have a notable influence both on the soil properties and on leaves phenol content and anti-radical capacity. The accessory N-fixing species seems to play a key role since, when Elaeagnus umbellata occurs, a marked decrease in leaf phenol content and the antiradical activities of both the investigated species is observed, while Alnus cordata positively affect phenols in Populus alba leaves, augmenting their radical scavenging capability.

Therefore, it is possible to consider a specific forest management as a tool for soils requalification and, at the same time, a source of income in a circular economy perspective.

How to cite: Danise, T., Guggenberger, G., Pacifico, S., Curcio, E., Innangi, M., and Fioretto, A.: Forests and forestry: intercropping effects on soil properties and leaves compounds in a circular economy perspective, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7682, https://doi.org/10.5194/egusphere-egu22-7682, 2022.

The increase in atmospheric CO₂ may lead to greater carbon uptake by plants and a subsequent increase in forest biomass stock. However, there are no direct field-based studies that assess this hypothesis in the Amazon forest, where the naturally low phosphorus (P) availability in the soil might reduce the assumed increase in biomass stock. Here, we evaluated the response of Inga edulis Mart. seedlings, a native N-fixing tree species, to elevated CO₂ and P addition in a set of open-top chambers (OTCs) with a CO₂ enriched atmosphere of 200 ppm above the ambient concentration, installed in the understory of a forest in the central Amazon. Inside each OTC (four controls with ambient CO₂ - aCO₂, and four treatments with +200ppm CO₂ - eCO₂), six pots were installed with seeds of I. edulis, three in natural soil and three in fertilized soil with P concentration of 600mg/kg, resulting in 12 pots for each treatments (aCO₂; eCO₂; eCO₂+P; +P). After two years (November 2019 - September 2021), we measured the total aboveground biomass, stem diameter at the base (mm), plant height (cm), stem density (g.cm^-3), leaf area (cm²), specific leaf area (SLA, cm².g^-1), thickness (µm), stomatal density, and chlorophyll content index (CCI). Irrespective of +P, SLA was significantly lower under eCO₂, but none of the other parameters analysed showed a strong response to eCO₂. Under +P treatment the number of leaves, leaf area, height, and total biomass increased significantly compared to control, but increased less than under eCO₂+P. Height was also higher under +P when compared to eCO₂. However, eCO₂ in combination with P addition (eCO₂+P) had major effects on aboveground biomass and leaf area, leading to a significant and strong increase of total leaf area (377%), aboveground plant biomass (373%), number of leaves (187%), total height (164%), and also a decrease in the CCI compared to controls and eCO₂ (except for the number of leaves, which was different only compared to the control), suggesting that the response to eCO₂ is limited by P availability. No significant changes were observed in stomatal density, leaf thickness, stem density, and stem diameter. Our findings suggest a directional shift of photosynthetic tissue under eCO₂ towards greater resource conservation through higher investment of dry mass per area (lower SLA), increasing protection against herbivores, pathogens, and mechanical damage. Despite the total biomass also increased under +P (203%), the biomass allocation to leaves and trunk resulted in a greater accumulation of biomass under eCO₂+P (373%). Nevertheless, the eCO₂+P supply provided a clear change in the resource use strategy, with plants investing mainly in light-capture-related traits, and more resistant leaves. These results showed an effect of eCO₂ when P limitation was alleviated, indicating, that in the future the role of this ecosystem as a carbon sink may be highly limited by the availability of P. However, we still need to understand whether these responses from seedlings in an understory forest will be effectively maintained in the canopy, through the full-ecosystem AmazonFACE experiment.

How to cite: Aleixo, I. F. and the AmazonFACE team: The role of elevated CO2 and phosphorus addition in aboveground biomass and functional traits of Inga edulis Mart. seedlings in a Central Amazon understory, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8936, https://doi.org/10.5194/egusphere-egu22-8936, 2022.

Forest dieback phenomena occur all over the world and have been mainly attributed to extreme droughts and heatwaves. These phenomena are more pronounced in the Mediterranean basin, causing a significant impact on the structure, composition, and productivity of forests. Understanding the response of Mediterranean forests to extreme climate events is of paramount importance to assess their vulnerability to such phenomena. The present study combined both radial growth data and remotely sensed indices (i.e., Normalized Difference Vegetation Index, NDVI) to analyse the vegetation status of selected deciduous forest stands impacted by the summer 2017 heatwave. We surveyed several sites of the Southern Apennines mountains range in order to: I) investigate the growth response of forest vegetation in terms of resilience and resistance and II) characterize their ability to recover after extreme climatic events. Overall, we observe a significant reduction in radial growth after 2017 in all studied stands. Moreover, the vegetation shows clear signs of "recovery" that are strictly dependent on species-specific and site-specific conditions. In this study we will highlight how these stands responded to the heatwave occurred in the 2017 and how these events can affect the future vegetation dynamics either in terms of growth and evolution of Mediterranean ecosystems.

How to cite: Italiano, S. S. P., Rita, A., Borghetti, M., Colangelo, M., Cantiani, M., Lapolla, A., and Ripullone, F.: Survey on the vulnerability and resilience of southern Italian forests to extreme climate events, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9200, https://doi.org/10.5194/egusphere-egu22-9200, 2022.

For Space exploration, the realization of long-term manned missions requires the possibility to grow plants in extra-terrestrial environments. Indeed, life support in Space will be based on the in situ regeneration of resources (e.g. air, water and food) needed by the crew that can be achieved in plant-based closed artificial ecosystems. At the same time the cultivation of edible plants can be useful to integrate astronauts’ diet with fresh food directly produced onboard of Space platforms.

In this context the production of microgreens is gaining popularity as easy ‘vegetal systems’ that can be grown in a few days, in small volume, providing high nutritional values.

 However, one of the main constraints for the in-orbit production of fresh food of vegetable origin is the establishment of scientific requirements for a flight apparatus dedicated to the production of such species.

In this study we used a multidisciplinary approach to understand the effects of the environmental factors on morpho-functional and biochemical aspects of different species of microgreens.

To do so, we set-up various growth chamber experiments to test different type of substrate, nutritional solutions, light intensities and VPDs (vapour pressure deficits) on Brassica oleracea var. sabauda cv. Vertus and Raphanus raphanistrum subsp. sativus cv. Saxa microgreens. In additional experiments, we evaluated the effect of different light qualities (red, blue and optimum spectrum) on the biometric, qualitative and anatomical parameters of Petroselinum crispum.

More specifically, once obtained the optimum light spectrum, we tested two type of substrates (cellulose sponge and coconut fiber) and two nutritional solutions (quarter strength throughout the cycle vs. half strength for the first half of the cycle followed by osmotic water during the second half). Then, using the quarter strength nutrient solution throughout the cycle and the coconut fiber substrate, we tested two different light intensities of an optimum light spectrum (300 µmol photons m^-2s^-1 vs. 150 µmol photons m^-2s^-1) and two different VPD levels (low VPD of 0.3 KPa and high VPD of 1.2 kPa).

To understand the best combination of environmental factors on microgreens growth in small controlled artificial systems, we compared the biomass production, morphological traits, visual quality parameters (through the leaf colorimetry coordinates) and biochemical traits including chlorophylls, anthocyanins, ascorbic acids, and soluble sugars content. Microgreens were then collected and subjected to the preparation for microscopy analyses to detect possible environmental factor-induced modifications to the anatomical structure.

The overall analysis showed that the microgreens-response is strictly influenced by environmental factors. Results suggested that the possible occurrence of positive outcomes (increments in antioxidant and biomass production) in microgreens can be severely influenced by environmental conditions: such a phenomenon should be taken into account in the design of plant-based modules for crop production in Space.The outcomes of this study will also be helpful to optimize microgreens production in controlled environment agriculture systems on Earth.

How to cite: Amitrano, C., El Nakhel, C., Rouphael, Y., Paradiso, R., Proietti, S., Battistelli, A., Caputo, R., and De Pascale, S.: The analysis of morpho-functional and nutritional traits of microgreens to define growth requirements in Space cultivation systems., EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9974, https://doi.org/10.5194/egusphere-egu22-9974, 2022.

Xylem is a multifunctional tissue that allows water transport, mechanical support, and storage of nutrients. These functions are provided by different cells, with different anatomy among species but also within individual trees. For the latter, it is well established that such anatomical disposition does not remain fixed but it is subject to a suite of adaptations induced by physiological constraints driven by both ontogenetic development and environmental characteristics.

For these reasons, in this study, we assessed 1) the spatial distribution of xylem conduits and their aggregation inside Fagus sylvatica L. tree-rings, and 2) the systematic variation of tip-to-base conduit widening and conduit packing occurring during tree growth.

In order to achieve these goals, we quantified the axial and radial xylem conduit patterns through measurement of conduit anatomical characteristics inside every tree-ring along complete radial series taken at different stem heights in eight Fagus sylvatica L. trees, sampled from two different sites in the Italian Apennines.

Our results showed a significant effect of the distance from the tree base and a weak effect of cambial age on the nearest neighbour distance among xylem conduits, suggesting that conduits were closer to each other near the apex, and became progressively more distant toward the base. However, point pattern profiles clearly highlighted a lack of aggregation between conduits along the stems.

In addition, the axial scaling of conduits (β) follows a power trajectory according to the theoretical prediction, while the xylem conduits packing exponent (α) was lower than the predicted Sperry’s packing rule. Furthermore, no consistent trend was found for the scaling exponent (β) during tree ontogeny, confirming that tip-to-base conduit widening is an adaptation, favored by natural selection to minimize the increase in hydraulic resistance when the individual stem grows longer and conductive path length increases.

How to cite: Pericolo, O., Rita, A., Tumajer, J., Ripullone, F., Gentilesca, T., Saracino, A., Nola, P., and Borghetti, M.: Tip-to-base conduit widening and spatial distribution of xylem conduits along the stem of Fagus sylvatica L., EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11434, https://doi.org/10.5194/egusphere-egu22-11434, 2022.