Reducibility for a class of weakly dispersive linear operators arising from the Degasperis Procesi equation

We prove reducibility of a class of quasi-periodically forced linear equations of the form $$\partial_tu-\partial_x\circ (1+a(\omega t, x))u+\mathcal{Q}(\omega t)u=0,\quad x\in\mathbb{T}:=\mathbb{R}/2\pi\mathbb{Z},$$ where $u=u(t,x)$, $a$ is a small, $C^{\infty}$ function, $\mathcal{Q}$ is a pseudo differential operator of order $-1$, provided that $\omega\in\mathbb{R}^{\nu}$ satisfies appropriate non-resonance conditions. Such PDEs arise by linearizing the Degasperis-Procesi (DP) equation at a small amplitude quasi-periodic function. Our work provides a first fundamental step in developing a KAM theory for perturbations of the DP equation on the circle. Following \cite{Airy}, our approach is based on two main points: first a reduction in orders based on an Egorov type theorem then a KAM diagonalization scheme. In both steps the key difficulites arise from the asymptotically linear dispersion law. In view of the application to the nonlinear context we prove sharp \emph{tame} bounds on the diagonalizing change of variables. We remark that the strategy and the techniques proposed are applicable for proving reducibility of more general classes of linear pseudo differential first order operators

Strobilurin Effects on Nitrogen Use Efficiency for the Yield and Protein in Durum Wheat Grown under Rainfed Mediterranean Conditions

In wheat, the increase in nitrogen use efficiency (NUE) and optimization of the nitrogen doses to be used are both very important aspects for improving sustainable and productive agriculture. The aim of this study was to investigate, under rainfed Mediterranean conditions, the influence of strobilurin treatment and N fertilization on durum wheat N use efficiency for yield (NUEy) and protein (NUEp) and on the contribution of their components, nitrogen uptake efficiency (UPE) and nitrogen utilization efficiency (NUtE). Two durum wheat cultivars (Saragolla and Sfinge) were grown for two years in field conditions under five nitrogen treatments (60 kg ha−1 N60; 90 and 120 kg ha−1 given two and three times; N90, N90T3, N120 and N120T3) comparing a control without strobilurin treatment (ST0) and one application of strobilurin (STaz). In Sfinge, STaz caused a decrease in UPE and NUEp and an increase in NUtE and NUEy. In Saragolla, the opposite behavior was observed. Moreover, strobilurin positively affected the contribution of UPE and negatively that of NUtE to NUEy only in Saragolla. Furthermore, strobilurin determined higher NUEy and NUEp values under most of the N treatments adopted in the drier year. With this study, we supported the hypothesis that in Mediterranean conditions, the possibility of reducing N rate application from 120 to 90 kg ha−1 with a strobilurin-based treatment, even in the absence of fungal diseases, could represent a useful agronomic strategy for durum wheat grown under drought conditions as those predicted under the ongoing climate change

Analysis of gluten proteins composition during grain filling in two durum wheat cultivars submitted to two water regimes

Durum wheat ( Triticum turgidum L. subsp . durum) is one of the major crops in the Mediterranean basin, where water stress often occurs during grain filling which represents a critical stage for the synthesis and accumulation of storage proteins (gliadins and glutenins). The aim of the study is to evaluate, by two-dimensional gel electrophoresis (2DE SDS-PAGE), the storage proteins composition of two durum wheat cultivars (Ciccio and Svevo) cultivated in a growth chamber under two different water regimes (control and water deficit). At milk stage and physiological maturity, gluten proteins have been extracted and separated by 2DE SDS-PAGE. The analysis of the gels was performed by the software ImageMaster 2D Platinum (Amersham). The results showed differences in protein expression within the different gel regions between water regimes and cultivars; under water deficit the rate of protein accumulation was faster for all the protein regions, either at milk and physiological stage. Protein accumulation within high molecular weight (H) region resulted faster in Ciccio than in Svevo mainly in the control treatment. In the low molecular weight region between 48 and 35 kDa (L 48-35), the cultivar Ciccio showed a higher protein expression than Svevo. Furthermore under water deficit a marked increase in H region volume and a decrease in the L 48-35 region was observed only for Svevo; instead in Ciccio no change was observed showing this cultivar a greater stability on changing water regime. Further studies by the use of mass spectrometry are necessary to identify specific peptides relative to drought stress during grain filling as well as to investigate the relationships with technological quality

Effect of Arbuscular Mycorrhizal Fungal Seed Coating on Grain Protein and Mineral Composition of Old and Modern Bread Wheat Genotypes

The effect of arbuscular mycorrhizal fungi (AMF) on yield and quality was investigated on a set of seven bread wheat genotypes with varying years of release, including five old genotypes and two modern varieties. A two-year field trial was conducted in central Italy under rainfed con- ditions. The effect of AM fungal seed coating was proved by assessing the AM fungal root colonization and studied on agronomic and quality traits, and in particular on gluten-forming proteins and grain mineral composition. AMF seed coating led to a general yield improvement in old geno- types (+24%). Concerning the effects on grain quality, while modern genotypes showed an increase in protein content (+16%), in the old ones an improvement of gluten quality was observed, with an increased proportion of HMW-GS from +17% to +92%. The gluten index results were mostly influenced by HMW-GS allelic configuration and amount, showing a significant correlation with gliadin- to-glutenin ratio and HMW-GS to LMW-GS. Concerning mineral uptake, AM fungal treatment de- termined a general increase in P content, which was more marked in the modern group (+44%). Furthermore, AMF significantly increased mean Fe concentration in Verna (+53%) and Bologna (+45%). Finally, phytate content did not increase with AMF, without affecting mineral bioavailability

Irrigation with treated municipal wastewater on artichoke crop: assessment of soil and yield heavy metal content and human risk

Industrial and municipal wastewaters are often used for irrigating agricultural fields in arid and semi-arid countries, representing the most attractive option to alleviate pressure on fresh-water resources. However, the wastewater may contain various potentially toxic elements and organic matters with highly harmful effects on human and animal health. During two growing seasons of globe artichoke, the effects of irrigation with secondary (SWW) and tertiary (TWW) municipal wastewater on heavy metal soil and plant content were evaluated together with the consequent human risk from artichoke head consumption. The heavy metal contents (i.e., Al, Cd, Co, Cr, Cu, Fe, Ni, Pb, Zn, and Mn) of the irrigation water, soil, plant and yield were analyzed. Total and extractable heavy metals were quantified to determine the bioaccumulation factors, and the health risks to adults and children were determined according to hazard indices. The heavy metal contents of the artichoke heads harvested after SWW and TWW irrigation were lower than the international threshold values and low bioaccumulation factors suggested that these heavy metals did not accumulate in the edible part of the artichoke crop. The hazard indices based on the consumption of the artichoke heads remained <1.0 for both adults and children, thus indicating that the health risks involving the different heavy metals are not significant

combined effects of deficit irrigation and strobilurin application on gas exchange yield and water use efficiency in tomato solanum lycopersicum l

Abstract Water is the major factor limiting plant productivity in many regions of the world. The aim of this study was to evaluate the combined effect of deficit irrigation (restitution of 100%, 50% and 0% of plant consumption: WR100, WR50 and WR0, respectively) and strobilurin treatment (no agrochemical added vs azoxystrobin treatment) in two tomato genotypes, IT-22/025, a wild-type plant, and Ikram, a commercial hybrid. Water use efficiency (WUE), physiological, yield and quality parameters and the expression of ERD15, a gene involved in abiotic stress response were evaluated. The two genotypes showed a different behaviour in response to water stress. Stomatal conductance decrease from WR100 to WR50 was in mean 27.5% for IT-22/025 and 44.5% for Ikram. Moreover, in Ikram, water stress decreased transpiration more than assimilation rate, while the opposite occurred in IT-22/025. The ERD15 expression decrease from WR100 to WR50 was higher for IT-22/025. These effects corresponded to higher total fresh fruit yield and WUE for IT-22/025. Strobilurin determined lower stomata conductance, maintaining higher assimilation rate, leading to an increase in WUE in WR0. Finally, strobilurin caused an increase in ERD15 expression only in IT-22/025. This study underlines the possibility to reduce the water used in tomato crop, maintaining acceptable yield and quality, by using agronomic and genetic strategy