The impact of winter flooding with saline water on foliar carbon uptake and the volatile fraction of leaves and fruits of lemon (Citrus limon) trees

We investigated the consequences of recurrent winter flooding with saline water on a lemon (Citrus limon (L.) Burm.f.) orchard, focussing on photosynthesis limitations and emission of secondary metabolites (isoprenoids) from leaves and fruits. Measurements were carried out immediately after flooding (December), at the end of winter (April) and after a dry summer in which plants were irrigated with optimal quality water (September). Photosynthesis was negatively affected by flooding. The effect was still visible at the end of winter, whereas the photosynthetic rate was fully recovered after summer, indicating an unexpected resilience capacity of flooded plants. Photosynthesis inhibition by flooding was not due to diffusive limitations to CO2 entry into the leaf, as indicated by measurements of stomatal conductance and intercellular CO2 concentration. Biochemical and photochemical limitations seemed to play a more important role in limiting the photosynthesis of flooded plants. In young leaves, characterised by high rates of mitochondrial respiration, respiratory rates were enhanced by flooding. Flooding transiently caused large and rapid emission of several volatile isoprenoids. Emission of limonene, the most abundant compound, was stimulated in the leaves, and in young and mature fruits. Flooding changed the blend of emitted isoprenoids, but only few changes were observed in the stored isoprenoids pool.

Climatic signals of tree-ring in Quercus gussonei (Borz\uec) Brullo in the Mediterranean region

Change in growth is among the primary response of trees to environmental variation. Tree-rings contain a wealth of information related to the climatic conditions. A dendroclimatic study on Quercus gussonei (Borz\uec) Brullo was carried out in the Nature Reserve of \u201cBosco della Ficuzza, Rocca Busambra, Bosco Del Cappelliere, Gorgo Del Drago\u201d (southern Italy). Q. gussonei is an endemic deciduous oak and thermophilous form of Quercus cerris L. that is found only in Sicily, although with clear sign of decline. The knowledge of ecology of this species should help to establish criteria for forest conservation in the Mediterranean region. For definining the ecological character and understanding the potential causes of the oak decline, we collected cores from ten trees with an increment borer. Precipitation and temperature data were obtained from a meteorological station located nearby from the stand. Annual ring widths, earlywood and latewood analyses were used in order to investigate and better understand the climatic dynamics influencing the oaks\u2019 growth. We determined the stable isotope discrimination of carbon (D13C) in the wood in order to investigate wateruse efficiency variations and the expression of possible plant adaptive traits. Climate-growth relationship, for the chronology 1951-2008, were analyzed using response, correlation and moving correlation functions. Our finding mostly highlight relationships between tree-rings width and climate data. Furthermore, D13C in treerings was used to identify long-term adjustments in water-use efficiency

Relationship between recruitment and mother plant vitality in the alien species Acacia cyclops A. Cunn. ex G. Don

Acacia cyclops is a widespread invader in Mediterranean-climate regions. However, although its naturalization in the Mediterranean Basin dates back only a few years ago, and the invasion process has not been studied hitherto. We investigated seedlings recruitment strategy adopted by A. cyclops in a small island (Lampedusa, Italy) where its natural regeneration was strictly confined under mother plants canopy. Healthy plants (DCP), plants at incipient senescence (SCP) and dead plants (DP) were distinguished according to vitality and canopy status. Living plants were also characterized in relation to leaf C and N isotope composition. Regeneration pattern (seedlings and saplings abundance) was related to the microclimatic differences (soil temperature, air temperature and humidity, soil nutrients, light) observed between canopies and adjacent open areas, and among canopy types. Living canopies ensure milder conditions, reducing extreme values as well as fluctuations between night and day. However, beneath canopies (DP, SCP and DCP) seedlings may benefit from significantly higher soil nutrients content than in the outside, while light availability was much higher under DP. Saplings to seedlings ratio was found to be around 12 under DP, while under SCP it was slightly higher than 1, and just less than 0.5 under DCP. Moreover, saplings growth was significantly higher under SCP and DP, suggesting a prominent role of light in driving seedlings recruitment. Stable isotope analyses of C and N provided ecophysiological information in relation to changes in canopies structure. Thus, while seedling stage appears to be more nutrient-limited, subsequent sapling stage is much more light-limited. Although the species is not yet displaying an invasive spreading on the island, our study provides clear evidence that senescent canopies are better facilitators than healthy in preserving the invasive potential of A. cyclops. This finding suggests some best practices in order to gradually reduce the presence of the alien species within its pristine nuclei of introduction

Temperature responses of Rubisco from Paniceae grasses provide opportunities for improving C3 photosynthesis.

Enhancing the catalytic properties of the CO2-fixing enzyme Rubisco is a target for improving agricultural crop productivity. Here, we reveal extensive diversity in the kinetic response between 10 and 37 °C by Rubisco from C3 and C4 species within the grass tribe Paniceae. The CO2 fixation rate (kcatc) for Rubisco from the C4 grasses with nicotinamide adenine dinucleotide (NAD) phosphate malic enzyme (NADP-ME) and phosphoenolpyruvate carboxykinase (PCK) photosynthetic pathways was twofold greater than the kcatc of Rubisco from NAD-ME species across all temperatures. The declining response of CO2/O2 specificity with increasing temperature was less pronounced for PCK and NADP-ME Rubisco, which would be advantageous in warmer climates relative to the NAD-ME grasses. Modelled variation in the temperature kinetics of Paniceae C3 Rubisco and PCK Rubisco differentially stimulated C3 photosynthesis relative to tobacco above and below 25 °C under current and elevated CO2. Amino acid substitutions in the large subunit that could account for the catalytic variation among Paniceae Rubisco are identified; however, incompatibilities with Paniceae Rubisco biogenesis in tobacco hindered their mutagenic testing by chloroplast transformation. Circumventing these bioengineering limitations is critical to tailoring the properties of crop Rubisco to suit future climates

Laparoscopic right hemicolectomy: a SICE (Società Italiana di Chirurgia Endoscopica e Nuove tecnologie) network prospective study on the approach to right colon lymphadenectomy in Italy: is there a standard?—CoDIG 2 (ColonDx Italian Group)

Background: Colon cancer is a disease with a worldwide spread. Surgery is the best option for the treatment of advanced colon cancer, but some aspects are still debated, such as the extent of lymphadenectomy. In Japanese guidelines, the gold standard was D3 dissection to remove the central lymph nodes (203, 213, and 223), but in 2009, Hoenberger et al. introduced the concept of complete mesocolic excision, in which surgical dissection follows the embryological planes to remove the mesentery entirely to prevent leakage of cancer cells and collect more lymph nodes. Our study describes how lymphadenectomy is currently performed in major Italian centers with an unclear indication on the type of lymphadenectomy that should be performed during right hemicolectomy (RH). Methods: CoDIG 2 is an observational multicenter national study that involves 76 Italian general surgery wards highly specialized in colorectal surgery. Each center was asked not to modify their usual surgical and clinical practices. The aim of the study was to assess the preference of Italian surgeons on the type of lymphadenectomy to perform during RH and the rise of any new trends or modifications in habits compared to the findings of the CoDIG 1 study conducted 4 years ago. Results: A total of 788 patients were enrolled. The most commonly used surgical technique was laparoscopic (82.1%) with intracorporeal (73.4%), side-to-side (98.7%), or isoperistaltic (96.0%) anastomosis. The lymph nodes at the origin of the vessels were harvested in an inferior number of cases (203, 213, and 223: 42.4%, 31.1%, and 20.3%, respectively). A comparison between CoDIG 1 and CoDIG 2 showed a stable trend in surgical techniques and complications, with an increase in the robotic approach (7.7% vs. 12.3%). Conclusions: This analysis shows how lymphadenectomy is performed in Italy to achieve oncological outcomes in RH, although the technique to achieve a higher lymph node count has not yet been standardized. Trial registration (ClinicalTrials.gov) ID: NCT05943951

Effects of Arbuscular Mycorrhizal Fungi on the Vegetative Vigor of Ailanthus altissima (Mill.) Swingle Seedlings under Sustained Pot Limitation

In order to invade new ecosystems, invasive alien plants need to cope with different microbial communities. Whilst the ability to avoid antagonists is well recognized, the opportunity to establish mutualistic associations is less known, even in widespread invasive species such as Ailanthus altissima (Mill.) Swingle. We sought to evaluate whether the beneficial effects of arbuscular mycorrhizal fungi (AMF) on Ailanthus seedlings are maintained over time, under prolonged pot limitation. We compared three-month-, three-year- and four-year-old mycorrhizal seedlings grown in natural forest soil (NT) with seedlings grown in sterilized (ST) and non-mycorrhizal (NM) soils, in pots of 3.4 L (22 x 15 cm). Growth parameters and leaf traits were assessed, including carbon (13C) and nitrogen (15N) stable isotope compositions. NT seedlings showed relatively higher vigor in the early stage but, subsequently, the benefits provided by AMF were lost. Interestingly, mycorrhizal seedlings consistently showed about 2‰ 13C enrichment, relatively to the other treatments. Negative linear relationships between leaf 13C and N content were found. Higher photosynthesis rates and WUE are the likely causes of the early enhanced growth in mycorrhizal seedlings. The symbiotic relationship between AMF and Ailanthus could be driven by resource availability. Greater insights into such aspects could provide an improved perspective on the ecological limits of Ailanthu

Self-Organizing Deep Learning (SO-UNet)—A Novel Framework to Classify Urban and Peri-Urban Forests

Forest-type classification is a very complex and difficult subject. The complexity increases with urban and peri-urban forests because of the variety of features that exist in remote sensing images. The success of forest management that includes forest preservation depends strongly on the accuracy of forest-type classification. Several classification methods are used to map urban and peri-urban forests and to identify healthy and non-healthy ones. Some of these methods have shown success in the classification of forests where others failed. The successful methods used specific remote sensing data technology, such as hyper-spectral and very high spatial resolution (VHR) images. However, both VHR and hyper-spectral sensors are very expensive, and hyper-spectral sensors are not widely available on satellite platforms, unlike multi-spectral sensors. Moreover, aerial images are limited in use, very expensive, and hard to arrange and manage. To solve the aforementioned problems, an advanced method, self-organizing–deep learning (SO-UNet), was created to classify forests in the urban and peri-urban environment using multi-spectral, multi-temporal, and medium spatial resolution Sentinel-2 images. SO-UNet is a combination of two different machine learning technologies: artificial neural network unsupervised self-organizing maps and deep learning UNet. Many experiments have been conducted, and the results showed that SO-UNet overwhelms UNet significantly. The experiments encompassed different settings for the parameters that control the algorithms