Ethylene and Chitosan Affected the Seed Yield Components of Onion Depending More on the Dose than Timing of Application

(1) Background: the production of onion seeds is limited by the competition between seeds and the vegetative organs and by scape lodging. However, information on the effects of plant growth regulation on onion seed production is scarce. Aim of the present study was to evaluate the seed yield components and germination ability of onion seeds as affected by the timing and dose of an ethylene application, a plant growth regulator able to modulate shoot–flower competition; and chitosan, an elicitor of plant defense mechanisms able to increase its tolerance to various stresses. (2) Methods: Onion was treated with ethylene at the recommended dose (100% RD) of a commercial product, at 150% RD in two contrasting phenological phases or untreated (control), or ‘with’ or ‘without’ chitosan, and the seed yield components and germination trend were measured. (3) Results: 100% RD at an early phase of growth did not influence the seed yield and increased the thousand seed weight (TSW) by 3.2%. The application of 150% RD decreased the seed yield by 33.5%, and this occurred irrespective of the timing of application. Such decreases were due to a reduction in the number of seeds per flower. The application of chitosan did not affect the crop at 100% RD and increased the seed yield and slightly increased, but not significantly, the TSW under 150% RD. Germination of the fresh seed was 92%, and 17 months of aging reduced it by 14%, with no effects of the treatments on the germination pattern. (4) Conclusions: the ethylene application mostly affected TSW but not the yield, whereas high doses of ethylene reduced yields irrespective of the timing of application. Such a result may have been due to a delay in the flowering onset that occurred in a relatively dry month. Chitosan sustained its yield when the yield potential was reduced by 150% RD, and such a result was likely due to physical protection from the transpiration since the synthetic fungicides applied did not likely allow the pathogens to infections. These results have implications for establishing the timing and dose of application of plant growth regulators and elicitors in seed onions to sustain the seed quality

Prevalence of hypertension in a large cohort of Italian hemodialysis patients: results of a cross-sectional study

Background: Hypertension is very common among patients receiving hemodialysis; however, little is known about its prevalence and control following the publication of the Kidney Disease Outcomes Quality Initiative (KDOQI) recommendations. Methods: This was a multicenter, observational, prospective, cross-sectional study aimed at evaluating the prevalence of hypertension and its awareness in a large sample of hemodialysis patients in Italy, and assessing possible relationships between high blood pressure (BP) values and traditional and nontraditional cardiovascular risk factors. Predialysis hypertension was defined as systolic BP (SBP)/diastolic BP (DBP) ≥140/90 mm Hg, and postdialysis hypertension as SBP/ DBP ≥130/80 mm Hg or the use of antihypertensive medications. Results: We collected data for 4,022 patients (men/ women 2,478/1,544, mean age 67.14 ± 14.08 years) from 77 dialysis centers. Of these, 2,832 patients (70.3%) were defined as having predialysis hypertension. At logistic regression analysis, diabetes, months on dialysis, serum albumin levels and treatment with erythropoiesis-stimulating agent (ESA) were independent factors predicting predialysis hypertension. Antihypertensive agents were used in 57.7% of the patients, leading to adequate BP control in only 40% of them. Factors independently predicting inadequate BP control were diabetes, ESA therapy, high serum cholesterol and higher Kt/V values. Conclusions: Hypertension is highly prevalent in this Italian hemodialysis population; achievement of adequate BP control is inadequate. It is unclear whether this may reflect suboptimal diagnosis or treatment of hypertension or, more likely, the allowance of higher predialysis BP values to try to avoid abrupt BP falls during the dialytic session