• Energy Research

Water deficit limiting yields is one of the negative aspects of climate change. However, this applies particularly when emphasis is on biomass production (e.g. for field crops), but not necessarily for plants where quality, not quantity is most relevant. For grapevine development, mild water stress occurring during specific phenological phases is an important factor when producing good quality wines. It induces the production of anthocyanins and aroma precursors and then could offer an opportunity to increase winegrower's income. A multidisciplinary study was carried out in Campania region (Southern Italy), an area well known for high quality wine production. Growth of Aglianico grapevine cultivar, with a standard clone population on 1103 Paulsen rootstocks, was studied on two different types of soil: Calcisols and Cambisols occurring along a slope of 90 m length with 11% gradient. The agro-hydrological model SWAP was calibrated and applied to estimate soil-plant water status during three consecutive seasons (2011-2013). Crop water stress index (CWSI), as estimated by the model, was related to leaf water potential, sugar content of grape bunches and wine quality (e.g. content of tannins). For both soils, the correlations between quality measurements and CWSI were high (e.g. - 0.97** with sugar; 0.895* with anthocyanins in the grape skins). The model was also applied to explore effects of future climate conditions (2021-2051) obtained from statistical downscaling of Global Circulation Models (AOGCM) and to estimate the effect of the climate on CWSI and hence on grape quality. Effects of climate change on grape quality indicate: (i) a resilient behavior of Calcisol to produce high quality wine, (ii) a good potentiality for improving the quality wine in Cambisol. The present study represents an example of multidisciplinary approach in which soil scientists, hydro-pedologists, crop modellers, plant physiologists and oenologists have integrated their knowledge and skills in order to deal with the complex interactions among different components of an agricultural system.

Su una coltura di soia, sono stati misurati i flussi dievapotraspirazione e di fotosintesi apparente mediante la tecnicamicrometereologica del rapporto di Bowen, integrata con lamisurazione dei gradienti della concentrazione di CO2. La coltura,che ha sviluppato una densa vegetazione (LAI massimo = 6.7), hadissipato sotto forma di calore latente la maggior partedell'energia disponibile. A tre mesi dalla semina, il valore mediodiurno del rapporto di Bowen risultato ancora relativamentebasso, e pari a 0.23. I valori di fotosintesi apparente sonorisultati minori di quelli riportati, per la stessa specie, daaltri Autori. Gli andamenti giornalieri dei flussi assimilativisono stati caratterizzati da fenomeni di isteresi, probabilmenteper effetto della maggiore attivit respiratoria nelle orepomeridiane. Il fenomeno si accentuato nel corso della stagionecolturale con l' intensificarsi dei processi di traslocazione degliassimilati above a soybean canopy, evapotranspiration and apparent canopy photosynthesis were monitored by the micrometeorologicaltechnique of the Bowen ratio energy balance (BREB), integrated withthe measurement of the CO2 concentration gradient. The dense canopy(maximum LAI = 6.7) managed to dissipate most of the availableenergy under the form of latent heat and even three months aftersowing, mean daytime Bowen ratio averaged 0.23. Apparent canopy photosynthesis rates were lower than reported elsewhere for soybean; daily trends showed typical hysteretic loops likely due tothe higher afternoon respiration rates. The loops were increasinglymore pronounced as the sink size increased along the season.

The soil salinity increase in the Mediterranean basin is one of the consequences of the climate change. The aim of this study was to evaluate the adaptability of giant reed (Arundo donax L.) to salinity, in conditions of higher temperatures, in order to hypothesise the future use of giant reed under these conditions. The trial was carried out in pots under a permanent metal structure, open on the sides and with a clear PE on the top. Four levels of soil salinity in the range 3.3-15.5 dS m(-1) were imposed. The stem number of the most stressed treatment was about 45% lower than the control and also the stem height was lower than in all other treatments. The green and yellow leaf number decreased as the soil salinity increased, and their sum was significantly lower in the two most stressed treatments. Osmotic potential of the leaf sap was not affected by salinity. Leaf water potential and stomatal conductance in the saline treatments were lower than in the control. Assimilation rate showed similar pattern of stomatal conductance. Intrinsic WUE remained almost stable until July and increased during August under the most stressful conditions. PSII photochemistry was not affected by soil salinity. Biomass yield was not different from the control until to soil ECe 12.0 dS m(-1): only the most stressed treatment (15.5 dS m(-1)) caused yield losses (50%). Tolerance threshold to salinity was 11.2 dS m(-1) and the relative yield losses were 11.6% per dS m(-1).

Given its high biomass and plasticity, Arundo donax L. is a promising ligno-cellulosic crop for cultivation in marginal lands in temperate climates. In order to test for adaptation to salinity, growth parameters of several A. donax clones were evaluated under two salt regimes in hydroponics. Mild NaCl stress (50 mM NaCl, 5.6 mS cm−1 EC, for 10 days) failed to discriminate between ecotypes, while a more severe NaCl treatment (150 mM, 18.8 mS cm−1 EC, for 21 days) enabled the identification of ecotypes maintaining plant growth under high salinity. Among several biometric parameters, 4th leaf width, and shoot and root DW consistently highlighted differences between ecotypes. Gas-exchange parameters also responded to severe NaCl treatment, while the photosystem efficiency was good, regardless of treatment. The results confirm that A. donax can be considered moderately tolerant to NaCl stress, with variation between ecotypes. Our screening protocol identified ecotypes with higher biomass production under severe NaCl treatment and can be useful for preliminary evaluation of NaCl tolerant clones for increasing productivity under salinity. The detected inter-ecotype variability could also be investigated to identify suitable clones for different environments.