Study on analytical characteristics of Nicotiana tabacum L., cv. Solaris biomass for potential uses in nutrition and biomethane production.

In order to limit the smoking tobacco sector crisis, a new non-GMO Nicotiana tabacum L. cv. Solaris was proposed as oil seed crop. Residues of oil extraction were successfully used in swine nutrition. The aim of this study was to explore the full potential of this innovative tobacco cultivar as multitasking feedstock non interfering with the food chain. In the triennium 2016-2018, samples from whole plant, inflorescence and stem-leaf biomass were collected in three experimental sites and analysed for chemical constituents, including fibre fractions, sugars and starch, macro-minerals and total alkaloids. The KOH soluble protein content and the amino-acid profile were also investigated as well as the biochemical methane potential. All the analyses were performed according to official methods and results were compared with values reported in literature for conventional lignocellulosic crops and agro-industry residues. The average protein content, ranging from 16.01 to 18.98 g 100 g-1 dry matter respectively for stem-leaf and whole plant samples, and their amino-acid profile are consistent with values reported for standard grass plant. These findings suggest the potential use of cv. Solaris in industrial food formulations. Moreover, considering the average content of both fibre available for fermentations (72.6% of Neutral Detergent Fibre) and oils and fats (7.92 g 100 g-1 dry matter), the whole plant biomass of cv. Solaris showed good attitude to anaerobic fermentation, confirmed by the biochemical methane potential of whole plant (168 Nm3 t-1 organic matter). Similarly, results allow to define the cv. Solaris biomass as a good quality forage apt to ensiling for its chemical composition. The low total alkaloids content of cv. Solaris, in average 0.3 g 100 g-1 dry matter, was previously reported not to affect growth performances and welfare traits of dairy heifers. These are the first results showing the multitasking potential use of cv. Solaris biomass, that could allow the recovery of tobacco cultivation know-how especially in marginal areas.

Variation in Ecophysiological Traits and Drought Tolerance of Beech (Fagus sylvatica L.) Seedlings from Different Populations.

Frequency and intensity of heat waves and drought events are expected to increase in Europe due to climate change. European beech (Fagus sylvatica L.) is one of the most important native tree species in Europe. Beech populations originating throughout its native range were selected for common-garden experiments with the aim to determine whether there are functional variations in drought stress responses among different populations. One-year old seedlings from four to seven beech populations were grown and drought-treated in a greenhouse, replicating the experiment at two contrasting sites, in Italy (Mediterranean mountains) and Germany (Central Europe). Experimental findings indicated that: (1) drought (water stress) mainly affected gas exchange describing a critical threshold of drought response between 30 and 26% SWA for photosynthetic rate and Ci/Ca, respectively; (2) the Ci to Ca ratio increased substantially with severe water stress suggesting a stable instantaneous water use efficiency and an efficient regulation capacity of water balance achieved by a tight stomatal control; (3) there was a different response to water stress among the considered beech populations, differently combining traits, although there was not a well-defined variability in drought tolerance. A combined analysis of functional and structural traits for detecting stress signals in beech seedlings is suggested to assess plant performance under limiting moisture conditions and, consequently, to estimate evolutionary potential of beech under a changing environmental scenario.