Le Comunità rurali nella Sardegna medievale (secoli XI-XV)

«L’esperienza legislativa dei Giudicati e successivamente l’esperienza della legislazione nazionale […], sono state le esperienze giuridicamente più intense della Sardegna, anche se in modi diversi […], e sono più intimamente penetrate nelle consuetudini locali, determinandone spesso la crisi totale, altre volte consentendo, stimolando e condizionando sul lato esterno, quella storia, interna al progresso delle consuetudini originarie, che definisce il più vasto orizzonte culturale delle esperienze autonome e originarie della cultura sarda, pur nei suoi residui arcaici». Così Antonio Pigliaru, professore di Filosofia del diritto nell’Università di Sassari, poneva nel suo La vendetta barbaricina come ordinamento giuridico (1959) il problema del rapporto tra la tradizione consuetudinaria e il sistema giuridico codificato. Pigliaru, ispirandosi alle teorie di Santi Romano, di Widar Cesarini Sforza e di Giuseppe Capograssi sulla pluralità degli ordinamenti, riteneva che la società agro-pastorale sarda avesse elaborato un sistema di norme e al suo interno, un «codice della vendetta», strutturato come un ordinamento giuridico autonomo, che avrebbe regolato le relazioni tra gli individui prescindendo dalle istituzioni dominanti, molto spesso identificate con gli apparati repressivi dello Stato (tribunali, carceri, caserme dei carabinieri). In sostanza Pigliaru ipotizzava che le comunità rurali della Sardegna avessero conservato inalterato nel tempo un patrimonio consuetudinario che affondava le radici negli istituti della normativa statutaria trecentesca e in particolare nella Carta de Logu d’Arborea

Effects of abscisic acid on ethylene biosynthesis and perception in Hibiscus rosa-sinensis L. flower development

The effect of the complex relationship between ethylene and abscisic acid (ABA) on flower development and senescence in Hibiscus rosa-sinensis L. was investigated. Ethylene biosynthetic (HrsACS and HrsACO) and receptor (HrsETR and HrsERS) genes were isolated and their expression evaluated in three different floral tissues (petals, style\u2013stigma plus stamens, and ovaries) of detached buds and open flowers. This was achieved through treatment with 0.1 mM 1-aminocyclopropane-1-carboxylic acid (ACC) solution, 500 nl l21 methylcyclopropene (1-MCP), and 0.1 mM ABA solution. Treatment with ACC and 1-MCP confirmed that flower senescence in hibiscus is ethylene dependent, and treatment with exogenous ABA suggested that ABA may play a role in this process. The 1-MCP impeded petal in-rolling and decreased ABA content in detached open flowers after 9 h. This was preceded by an earlier and sequential increase in ABA content in 1-MCP-treated petals and style\u2013stigma plus stamens between 1 h and 6 h. ACC treatment markedly accelerated flower senescence and increased ethylene production after 6 h and 9 h, particularly in style\u2013stigma plus stamens. Ethylene evolution was positively correlated in these floral tissues with the induction of the gene expression of ethylene biosynthetic and receptor genes. Finally, ABA negatively affected the ethylene biosynthetic pathway and tissue sensitivity in all flower tissues. Transcript abundance of HrsACS, HrsACO, HrsETR, and HrsERS was reduced by exogenous ABA treatment. This research underlines the regulatory effect of ABA on the ethylene biosynthetic and perception machinery at a physiological and molecular level when inhibitors or promoters of senescence are exogenously applied

Chlorophyll a Fluorescence as a Tool in Evaluating the Effects of ABA Content and Ethylene Inhibitors on Quality of Flowering Potted Bougainvillea

Flowering potted plants during the postproduction stage are usually stored in inadequate environmental conditions. We evaluated the effect of the most common storage conditions and treatments on two Bougainvillea cultivars after harvest and during recovery. Flowering potted Bougainvillea plants were treated with 100 mL 2 mM amino-oxyacetic acid (AOA) or 500 ppb 1-methylcyclopropene (1-MCP) prior storage in dark at 14°C for simulating transport or storage conditions and, subsequently, transferred to growth chambers at 20°C in the light for one week for evaluating the recovery ability. The plant stress during the experiments was assessed by ethylene, ABA, and chlorophyll a fluorescence measurements. Ethylene production was affected by temperature rather than treatments. ABA concentration declined in leaves and flowers during storage and was not affected by treatments. Fluorescence parameters appear to be very useful for screening Bougainvillea cultivars resistant to prolonged storage periods

Primordial black holes in the curvaton model: possible connections to pulsar timing arrays and dark matter

We revise primordial black holes (PBHs) production in the axion-curvaton model, in light of recent developments in the computation of their abundance accounting for non-gaussianities (NGs) in the curvature perturbation up to all orders. We find that NGs intrinsically generated in such scenarios have a relevant impact on the phenomenology associated to PBHs and, in particular, on the relation between the abundance and the signal of second-order gravitational waves. We show that this model could explain both the totality of dark matter in the asteroid mass range and the tentative signal reported by the NANOGrav and IPTA collaborations in the nano-Hz frequency range. En route, we provide a new, explicit computation of the power spectrum of curvature perturbations going beyond the sudden-decay approximation.Comment: 25 pages, 11 figure

Melatonin induces proline, secondary metabolites, sugars and antioxidants activity to regulate oxidative stress and ROS scavenging in salt stressed sword lily

Sword lily is regarded as a useful and commercially demanding cut flower crop; hence, assessing its responses to abiotic stress, particularly salt stress, is vital. Melatonin (MT) exhibits stress tolerance in crop plants and is an emerging stress relieving alternative to chemicals. Nevertheless, the possible process underlying the effects of MT under salt stress has yet to be fully elucidated in plants. Herein, the salt stress (SS) mitigation potential of MT was assessed in a commercially important cut flower, sword lily. Melatonin, expressed as MT1, MT2, MT3, and MT4, was administered at concentrations of 0.2, 0.4, 0.6, and 0.8 mM. The results revealed that SS (5 dS m−1) restricted the growth and physiological aspects of sword lily. Furthermore, malondialdehyde (MDA), hydrogen peroxide (H2O2), membrane permeability, endogenous proline, and soluble protein contents were enhanced in SS. MT application improved morphological traits, photosynthetic pigments, and corm traits. The application of MT mitigated the effects of SS stress in Gladiolus grandiflorus plants by improving growth and photosynthetic pigments. MT application under SS improved the reducing and non-reducing sugar and NPK contents of the sword lily. Furthermore, MT improved the levels of secondary metabolites, such as anthocyanins, flavonoids, and ascorbic acid, in sword lily. Moreover, MT supplementation ameliorated salt-induced oxidative stress in the gladiolus, as depicted by a decrease in stress markers (EL, MDA, and H2O2) and an increase in defense-related enzymes (POD, CAT, and SOD) with highest increase in the MT3 treatment under salinity stress. The SOD and CAT enzyme activities were 3–3.6-fold higher in the MT3 under stress than the control. In conclusion, MT applications on cut flowers can be an effective strategy to reduce salt stress and can be used to regulate salinity stress in cut flower production. MT can be used as a safe alternative to other agrochemicals to maintain the growth and flower quality of sword lilies, with beneficial effects during vase life

Spatial and temporal distribution of mineral nutrients and sugars throughout the lifespan of Hibiscus rosa-sinensis L. flower

AbstractAlthough the physiological and molecular mechanisms of flower development and senescence have been extensively investigated, a whole-flower partitioning study of mineral concentrations has not been carried out. In this work, the distribution of sucrose, total reducing sugars, dry and fresh weight and macro and micronutrients were analysed in Hibiscus rosa-sinensis L. petals, stylestigma including stamens and ovary at different developmental stages (bud, open and senescent flowers). Total reducing sugars showed the highest value in petals of bud flowers, then fell during the later stages of flower development whereas sucrose showed the highest value in petals of senescent flowers. In petals, nitrogen and phosphorus content increased during flower opening, then nitrogen level decreased in senescent flowers. The calcium, phosphorus and boron concentrations were highest in ovary tissues whatever the developmental stage. Overall, the data presented suggests that the high level of total reducing sugars prior the onset of flower opening contributes to support petal cells expansion, while the high amount of sucrose at the time of petal wilting may be viewed as a result of senescence. Furthermore, this study discusses how the accumulation of particular mineral nutrients can be considered in a tissue specific manner for the activation of processes directly connected with reproduction

Postharvest application of hydrogen peroxide and salicylic acid differently affects the quality and vase life of cut rose (Rosa hybrida L.) petals and leaves

Rose represents an important product in the market of cut flowers. Its quality is related to visual appearance and is affected by oxidative stress and senescence. To maintain the quality and extend the product vase life, innovative technical solutions to be applied in postharvest are needed. In this work the effectiveness of hydrogen peroxide (H2O2) and salicylic acid (SA), was assessed on cut rose leaves and petals. Several physiological indicators of quality were studied, including chlorophyll content, chlorophyll a fluorescence, color, lipid peroxidation, phenolic compounds and anthocyanins. After 7 days of vase life 73.33% of untreated roses were not marketable anymore, while the percentage was lower in response to treatments (47.06% in SA and 25.53% in H2O2). The application of H2O2 induced a reduction in leaf chlorophyll and in the performance index which, at the end of the vase life decrease by 76% and 49% respectively. Consistently, the lipid peroxidation in leaves treated with H2O2 increased by a 53%. After 4 days of vase life, SA allowed maintaining higher levels of anthocyanins in petals compared to H2O2 and to controls. The results obtained allowed individuating different responses, depending on the treatment applied as well as on the plant organ