Physiological and Biochemical Adaptive Traits in Leaves of Four Citrus Species Grown in an Italian Charterhouse

Citrus trees are a very important crops that are cultivated worldwide, but not much knowledge is known about the ecophysiological responses to climatic changes in trees under natural conditions. The aim of this study was to investigate their adaptive capacity in response to seasonal phenological and environmental changes. The trial included Citrus trees (sweet orange, bitter orange, lemon, mandarin) growing under non-regular cropping conditions in a Monumental Charterhouse in Tuscany, in a subtropical Mediterranean climate with hot summer conditions. During a 1-year field trial, we determined the variations in chlorophyll fluorescence parameters and leaf biochemical traits (content of chlorophylls and carotenoids, total phenolic content (TPC), total antioxidant capacity (TAC), and total non-structural carbohydrates). In all Citrus spp., interspecific mean values of photochemical efficiency peaked during the summer, while a marked photoinhibition occurred in the winter in concomitance with higher interspecific mean values of leaf TPC, TAC, and non-structural carbohydrates. The trees showed the pivotal role played by photosynthetic acclimation as a survival strategy to tolerate abiotic stress in the climate change hotspot of Mediterranean environment. This study is included in a wider project aimed at a new valorization of Citrus trees as genetic resource and its by-products with added-value applications for innovative functional foods

An initial comparison of the content of bitter substances in Cynara Scolymus L. plants obtained from rooted of shoots and micropropagation

Cynaropicrin, a sesquiterpene, is the main bitter compound in globe artichoke and is important for the organolectic and nutritional quality of the fresh product and leaf extracts. Artichoke plants of the late variety "Grato 1" obtained from rooted offshoots and by micropropagation were compared with respect to the bitter content in the young leaves and heads. The bitter content, expressed as cynaropicrin (% of dry weight), was determined by an alkalimetric method. The results show a bitter content ranging from 6.82 to 9.63%; the leaves of the micropropagated plants had 29% less bitter content than the plants traditionally propagated by rooted offshoots

Recycling Cigarette Filters as Plant Growing Substrate in Soilless System

Two massive wastes are cigarette butts (CB) and stone wool (SW), both representing a threat to the environment. Although the cellulose acetate filters (CAF) in CB are long‐term degradable, SW soilless substrates are not. Here, a soilless substrate for growing ornamental plants was manufactured with CAF and compared to commercial SW substrate. CB treatment consisted of a washing in boiling water with a dramatic reduction of pollutants in CAF. Then, cleaned filters were separated, dried, carded to fibers, and subsequently compacted into plugs. The trace pollutants in recycled CAF substrate did not negatively affect the germination of Spartium junceum L. and Lavandula angustifolia Miller seeds as well as the root development of Salvia officinalis L. and Salvia rosmarinus Schleid. stem cuttings. Plants grown in recycled CAF showed a differential species‐ dependent change of pigments in comparison with those in SW, without compromising their photosynthesis performance. Overall, the results demonstrated that these plants can be well established and grow in recycled CAF, as comparable to SW substrate. This study highlights a novel and promising solution in CAF recycling by turning this litter into an efficient soilless substrate for growing ornamental plants, thus limiting the use of SW and indirectly decreasing its industrial waste flow

Antioxidant activity and phenolic compounds in the edible parts of early and late italian artichoke (Cynara scolymus L.) varieties

The content of total phenolic compounds (TPC) and chlorogenic acid (CA) and the antioxidant activity in the methanolic extracts of edible parts of three early and two late Italian artichoke (Cynara scolymus L.) varieties were determined and compared. TPC content was determined by the Folin-Ciocalteu reagent and the antioxidant activity by the DPPH method. CA quantification was carried out by HPLC and GC/MS using CA methyl ester as internal standard. Results showed that artichoke varieties differ considerably in their TPC (7.31-13.05 mg/g fresh weight) and CA (1.36-2.46 mg/g fresh weight) content, as well as in their antioxidant activity. No significant correlation was observed between TPC content and DPPH scavenging activity. Boiling the inner bracts of the heads led to a 46% loss of CA

The role of Euglena gracilis paramylon in modulating xylem hormone levels, photosynthesis and water-use efficiency in Solanum lycopersicum L.

-1,3-glucans such as paramylon act as elicitors in plants, modifying the hormonal levels and the physiological responses. Plant hormones affect all phases of the plant life cycle and their responses to environmental stresses, both biotic and abiotic. The aim of this study was to investigate the effects of a root treatment with Euglena gracilis paramylon on xylem hormonal lev- els, photosynthetic performance and dehydration stress in tomato (Solanum lycopersicum). Paramylon granules were processed to obtain the linear fibrous structures capable to interact with tomato cell membrane. Modulation of hor- mone levels (abscisic acid, jasmonic acid and salicylic acid) and related phys- iological responses such as CO 2 assimilation rate, stomatal and mesophyll conductance, intercellular CO 2 concentration, transpiration rate, water-use efficiency, quantum yield of photosystem II and leaf water potential were investigated. The results indicate a clear dose-dependent effect of paramy- lon on the hormonal content of xylem sap, photosynthetic performance and dehydration tolerance. Paramylon has the capability to enhance plant defense capacity against abiotic stress, such as drought, by modulating the conduc- tance to CO 2 diffusion from air to the carboxylation sites and improving the water-use efficiency

Trichoderma harzianum T6776 modulates a complex metabolic network to stimulate tomato cv. Micro-Tom growth

Background and aims Trichoderma harzianum 6776 is a novel and beneficial tomato fungal isolate. To investigate the mechanisms underlying the T. harzianum 6776- tomato interaction, several physiological and biochemical responses were explored on dwarf tomato plants, cv. Micro-Tom. Methods Growth of treated and untreated plants was evaluated by measuring the height and biomass production of plants. The leaf pigment content and sugar partitioning in plant organs were evaluated by biochemical analysis. The photosynthetic parameters were measured by a miniaturized PAMfluorometer and a portable gas-exchange system. The hormonal analysis in root and xylem sap was performed by gas cromatographymass spectrometry (GC-MS). Results T. harzianum 6776 positively affected plant growth, increasing the leaf pigment content andimproving the photosynthetic activity at both stomatal and non-stomatal levels. Differences in pigment composition and photosynthetic performance were reflected in the carbohydrate content and their partitioning. In the absence of a pathogen, root and xylem vessel stress and growth-related hormone balance were affected by the interaction with T. harzianum 6776, with an increase in jasmonic and indoleacetic acids and a decrease in salicylic acid content. Conclusions This study shows the complex connection between increased hormone accumulation and transport, altered sugar partitioning and enhanced photosynthetic efficiency induced by T. harzianum 6776, and how growth promotion is the result of the combination of these drastic changes in Micro- Tom plants