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In natural environments, plants are exposed to variable light conditions, but photosynthesis has been mainly studied at steady state and this might overestimate carbon (C) uptake at the canopy scale. To better elucidate the role of light fluctuations on canopy photosynthesis, we investigated how the chlorophyll content, and therefore the different absorbance of light, would affect the quantum yield in fluctuating light conditions. For this purpose, we grew a commercial variety (Eiko) and a chlorophyll deficient mutant (MinnGold) either in fluctuating (F) or non-fluctuating (NF) light conditions with sinusoidal changes in irradiance. Two different light treatments were also applied: a low light treatment (LL; max 650 μmol m−2 s−1) and a high light treatment (HL; max 1,000 μmol m−2 s−1). Canopy gas exchanges were continuously measured throughout the experiment. We found no differences in C uptake in LL treatment, either under F or NF. Light fluctuations were instead detrimental for the chlorophyll deficient mutant in HL conditions only, while the green variety seemed to be well-adapted to them. Varieties adapted to fluctuating light might be identified to target the molecular mechanisms responsible for such adaptations.

Question: In the fall 2018 we observed an atypical pattern with concentric belts of green, yellow, and brown vegetation. What are the causes of the pattern? Localized water depletion, soil spatial heterogeneity and the activity of pathogenic organisms were tested as alternative hypotheses. Location: Banks of a water reservoir, Alento basin in south Italy (40°19′04.50″ N; 15°06′45.35″ E). Methods: Belts were monitored for floristic composition and plant health status. In each zone, 17 soil parameters were analysed (soil texture, pH, electrical conductivity, limestone content, organic C, Olsen P, total N, C/N ratio, cations exchange capacity, Ca2+, Mg2+, Na+, K+, Fe, Cu, Zn, Mn). Soil moisture was monitored by soil probes, positioned at 10cm depth. The incidence of pathogens and parasitic plants was visually estimated. Finally, model simulations were carried out to explore the interactions between biotic and abiotic factors in the formation of the belts. Results: The vegetation survey revealed that the green belt was characterized by a monospecific stand of Xanthium italicum with a plant density >190 individuals per m2. All plants were healthy. In the yellow belt, instead, Xanthium italicum was attacked by the parasitic plant Cuscuta campestris with an incidence >70%. In the brown belt all Xanthium italicum was still standing but dead, with an incidence of Cuscuta campestris attack >94%. No differences in soil chemistry were recorded in the three belts, while soil moisture was slightly lower in the green belt, likely as a result of a higher evapotranspiration rate. The modelling simulation well reproduced the banded vegetation, supporting the role of the parasitic plant in the formation of the pattern. Conclusions: By combining extensive field measurements with detailed modelling work, we revealed, for the first time, the primary role of a parasitic plant in the formation of a regular and ephemeral vegetation pattern.

In the light of unprecedented change in global biodiversity, real-time and accurate ecosystem and biodiversity assessments are becoming increasingly essential. Nevertheless, estimation of biodiversity using ecological field data can be difficult for several reasons. For instance, for very large areas, it is challenging to collect data that provide reliable information. Some of these restrictions in Earth observation can be avoided through the use ofremote sensingapproaches. Various studies have estimated biodiversity on the basis of the Spectral Variation Hypothesis (SVH). According to this hypothesis, spectral heterogeneity over the different pixel units of a spatial grid reflects a higher niche heterogeneity, allowing more organisms to coexist. Recently, the spectral species concept has been derived, following the consideration that spectral heterogeneity at a landscape scale corresponds to a combination of subspaces sharing a similarspectral signature. With the use of high resolution remote sensing data, on a local scale, these subspaces can be identified as separate spectral entities, the so called “spectral species”. Our approach extends this concept over wide spatial extents and to a higher level of biological organization. We applied this method toMODISimagery data across Europe. Obviously, in this case, a spectral species identified by MODIS is not associated to a singleplant speciesin the field but rather to a species assemblage, habitat, or ecosystem. Based on such spectral information, we propose a straightforward method to deriveα- (local relative abundance and richness of spectral species) andβ-diversity (turnover of spectral species) maps over wide geographical areas.

Background Obtaining instantaneous gas exchanges data is fundamental to gain information on photosynthesis. Leaf level data are reliable, but their scaling up to canopy scale is difficult as they are acquired in standard and/or controlled conditions, while natural environments are extremely dynamic. Responses to dynamic environmental conditions need to be considered, as measurements at steady state and their related models may overestimate total carbon (C) plant uptake. Results In this paper, we describe an automatic, low-cost measuring system composed of 12 open chambers (60 × 60 × 150 cm; around 400 euros per chamber) able to measure instantaneous CO2 and H2O gas exchanges, as well as environmental parameters, at canopy level. We tested the system’s performance by simulating different CO2 uptake and respiration levels using a tube filled with soda lime or pure CO2, respectively, and quantified its response time and measurement accuracy. We have been also able to evaluate the delayed response due to the dimension of the chambers, proposing a method to correct the data by taking into account the response time ($${t}_{0}$$ t 0 ) and the residence time (τ). Finally, we tested the system by growing a commercial soybean variety in fluctuating and non-fluctuating light, showing the system to be fast enough to capture fast dynamic conditions. At the end of the experiment, we compared cumulative fluxes with total plant dry biomass. Conclusions The system slightly over-estimated (+ 7.6%) the total C uptake, even though not significantly, confirming its ability in measuring the overall CO2 fluxes at canopy scale. Furthermore, the system resulted to be accurate and stable, allowing to estimate the response time and to determine steady state fluxes from unsteady state measured values. Thanks to the flexibility in the software and to the dimensions of the chambers, even if only tested in dynamic light conditions, the system is thought to be used for several applications and with different plant canopies by mimicking different environmental conditions.

Question: In the fall 2018 we observed an atypical pattern with concentric belts of green, yellow, and brown vegetation. What are the causes of the pattern? Localized water depletion, soil spatial heterogeneity and the activity of pathogenic organisms were tested as alternative hypotheses. Location: Banks of a water reservoir, Alento basin in south Italy (40°19′04.50″ N; 15°06′45.35″ E). Methods: Belts were monitored for floristic composition and plant health status. In each zone, 17 soil parameters were analysed (soil texture, pH, electrical conductivity, limestone content, organic C, Olsen P, total N, C/N ratio, cations exchange capacity, Ca2+, Mg2+, Na+, K+, Fe, Cu, Zn, Mn). Soil moisture was monitored by soil probes, positioned at 10 cm depth. The incidence of pathogens and parasitic plants was visually estimated. Finally, model simulations were carried out to explore the interactions between biotic and abiotic factors in the formation of the belts. Results: The vegetation survey revealed that the green belt was characterized by a monospecific stand of Xanthium italicum with a plant density >190 individuals per m2. All plants were healthy. In the yellow belt, instead, Xanthium italicum was attacked by the parasitic plant Cuscuta campestris with an incidence >70%. In the brown belt all Xanthium italicum was still standing but dead, with an incidence of Cuscuta campestris attack >94%. No differences in soil chemistry were recorded in the three belts, while soil moisture was slightly lower in the green belt, likely as a result of a higher evapotranspiration rate. The modelling simulation well reproduced the banded vegetation, supporting the role of the parasitic plant in the formation of the pattern. Conclusions: By combining extensive field measurements with detailed modelling work, we revealed, for the first time, the primary role of a parasitic plant in the formation of a regular and ephemeral vegetation pattern.

37th European Photovoltaic Solar Energy Conference and Exhibition; 1972-1974, This paper introduces a recently initiated Italian national project on high innovative PV greenhouses considering different scales of experimentation as well as an interdisciplinary approach involving experts in different areas. At small scale, the light transmittance of spectrally selective solar cells devices, which focus different wavelengths on PV modules and plants, will be analyzed in order to obtain the best compromise between electricity production and photosynthesis. At medium and large scale, two greenhouses will be tested: (i) An experimental greenhouse (about 15 m2) equipped with different IoT sensors and innovative PV glasses technologies will monitor the growing environment together the energy production. (ii) Based on the results obtained in the medium scale greenhouse, some PV glasses will be used as envelope material for the renovation of a commercial-size greenhouse (about 100 m2). Both PV greenhouses will be located in a historic environment dating back to the XVIII century, the Botanical garden of Portici, which requires a careful approach to a correct integration with the landscape. Along the two years of the duration of the project is foreseen to finding the best compromise between functional characteristics (energy and food) and aesthetic ones, thus optimizing the integrated system showing the potential of innovative glasses for greenhouses.