A study was performed to determine the effect of the systemin polypeptide on the bio-protective effect of arbuscular mycorrhizal fungi (AMF) in tomato plants infected with Alternaria solani, Phytophthora infestans or P. parasitica. Before infection, tomato plants were colonized with two different AMF, Glomus fasciculatum or G. clarum. In addition, a group of inoculated plants was treated with systemin, just after emergence. The exogenous application of systemin marginally suppressed the resistance against A. solani leaf blight observed in G. fasciculatum mycorrhizal plants but significantly enhanced it in plants colonized with G. clarum. Systemin induced resistance to P. parasitica in leaves of G. fasciculatum mycorrhizal plants, in which AMF colonization alone was shown to have no protective effect. Conversely, none of the treatments led to resistance to root or stem rots caused by P. infestans or P. parasitica. The above effects did not correlate with changes in the activity levels of beta-1,3-glucanase (BG), chitinase (CHI), peroxidase (PRX), and phenylalanine ammonium lyase (PAL) in leaves of infected plants. However, they corroborated previous reports showing that colonization by AMF can lead to a systemic resistance response against A. solani. Systemic resistance to A. solani was similarly observed in non-mycorrhizal systemin-treated plants, which, in contrast, showed increased susceptibility to P. infestans and P. parasitica. The results indicated that the pattern of systemic disease resistance conferred by mycorrhizal colonization was dependent on the AMF employed and could be altered by the exogenous application of systemin, by means of a still undefined mechanism.

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The potable water in residential hydraulic networks is measured using volumetric meters. However, when the water carries air bubbles or pockets through the pipes, the accuracy of the meter readings is reduced, which can negatively impact the billing that users pay for their water consumption. A check valve accessory exists that reduces the size of these air bubbles to correct the meter readings and improve the service experience. However, the device has only been tested for networks with relative pressures higher than 275.79 kPa. This research proposes to characterize the hydraulic behavior of the accessory through an experimental procedure in which the operating conditions are similar to those found in water networks in Latin America, where the networks have relative pressures lower than 275.79 kPa. The study found that the accessory significantly reduces the coefficient of loss for velocities greater than 1 m/s. The use of the device is suggested in flow regimes with Reynolds numbers close to 20,000 for operating conditions of temperatures close to 25 °C and residential pipes with an internal diameter of 20.9 mm and a flow velocity between 1.3 m/s and 1.78 m/s. This condition allows it to operate with minimal local energy loss and a low coefficient of loss, providing an improved service experience.