The objective of this study was to investigate the effect of exogenous selenium (Se) supply (0, 2, 4, 8, 16 μM) on the growth, lipid peroxidation and antioxidative enzyme activity of 100 mM NaCl-stressed melon (Cucumis melo L.) seedlings. Salt stress significantly reduced the growth attributes including stem length, stem diameter, dry weight and increased antioxidative enzyme activity [superoxide dismutase (SOD), peroxidase (POD), catalase (CAT)]. Moreover, the plant exhibited a significant increase in electrolyte leakage and malondialdehyde (MDA) content under NaCl stress. Se supplementation not only improved the growth parameters but also successfully ameliorated the adverse effect caused by salt stress in melon seedlings. However, the mitigation of NaCl-stressed seedlings was different depending on the Se concentration. At lower concentrations (2–8 μM), Se improved growth and acted as antioxidant by inhibiting lipid peroxidation and increasing in SOD and POD enzymes activity under salt stress. At higher concentrations (16 μM), Se exerted diminished beneficial effects on growth. Whereas CAT activity was enhanced. The result indicated that Se supplementation had a positive physiological effect on the growth and development of salt-stressed melon seedlings.
In this study, LAMP markers linked to shelf-life in melon (Cucumis melo L.) were developed by converting a cleaved amplified polymorphic sequences (CAPS) marker (C2). The CAPS-PCR fragments from the long-shelf-life melon (0-3) and short-shelf-life melon (Nat-2) were cloned and sequenced to construct LAMP primers. A single nucleotide polymorphism (SNP) was identified between 0-3 and Nat-2. LAMP primers were designed to detect the SNP. In the LAMP reaction to detect long-shelf-life melon, the turbidity of the templates using 0-3, F1, homozygous long-shelf-life F2 lines and heterozygous long-shelf-life F2 lines started to increase after 40 min. In contrast, the turbidity of Nat-2 and homozygous short-shelf-life F2 lines did not increase even after 90 min. In the LAMP reaction to detect short-shelf-life melon, the turbidity of the templates using Nat-2, F1, homozygous short-shelf-life F2 lines and heterozygous long-shelf-life F2 lines started to increase after 40 min. But the turbidity of 0-3 and homozygous long-shelf-life F2 lines did not increase after 90 min. This attests to the high reliability and usefulness of LAMP for marker-assisted selection.
Foliar feeding of plants is an important supplementation of soil fertilization in vegetable cultivation. Foliar-fertilized plants deliver high yields of good quality at lower rates of mineral fertilization. In horticultural practice foliar fertilization is also recommended as the most effective method of supplying plants with nutrients under deficiency conditions. An experiment was established to evaluate an effect of foliar application with Florovit and combination Ekolist-Warzywa+Urea on the yield quality of six large-fruit melon cultivars (‘Pacstart’, ‘Yupi’, ‘Gattopardo’, ‘Polydor II’, ‘Seledyn’, ‘Legend’) cultivated in the climatic conditions of central-eastern Poland. The total yield was achieved from Florovit and Ekolist-fertilized plants did not differ significantly. A higher total yield was achieved from Florovit-fertilized plants compared with control object. ‘Yupi’ was characterised by higher total yields compared with the other cultivars. The greatest fruit number per 1 m2 was set by ‘Gattopardo’. On the basis of the results obtained it was found that, due to the highest share of marketable fruit, ‘Yupi’ is the cultivar recommended for cultivation under the growing conditions of central-eastern Poland. ‘Seledyn’ was gave at least unripe fruit whereas ‘Pacstart’ produced the lowest share of disease-affected fruit. An application of the foliar fertilizers reduced the total sugar and monosaccharides content in melon fruit. Regardless of the kind of foliar feeding, most dry matter in the fruit was produced by ‘Pacstart’, total sugar and monosaccharides by ‘Yupi’ and ascorbic acid by ‘Legend’.
A number of research studies investigating melon production technologies in various macroregions of Poland characterized by different climate conditions have been initiated to investigate the effect of perforated PE film and non-woven PP fabric covers as well as soil mulching with organic and mineral material on the melon growing process. A two-factorial field experiment was conducted in the years 2004–2008, in the Garden of the Research and Experimental Station of the University of Warmia and Mazury in Olsztyn. The first experimental factor were four Polish melon cultivars, Malaga F1, Melba, Oliwin and Seledyn F1, recommended for open ground and forced cultivation. The second factor were types of soil cover and plant cover. Apart from the control treatment (without protective cover), the effect of the following types of cover on the growth rate and yield of melon plants was determined in a five-year cycle: perforated PE film with 100 holes per m2, non-woven PP fabric with surface density of 17 g·m-2, black PE film for soil mulching; black PE film for soil mulching + perforated PE film with 100 holes per m2, black PE film for soil mulching + non-woven PP fabric. An analysis of the chemical composition of melon fruit showed that the concentrations of dry matter, L-ascorbic acid and total carbohydrates were higher in the edible parts of heterotic cultivars. The type of plant cover and soil cover had a significant effect on the dry matter content of the edible parts of melon, but it caused no considerable changes in the levels of the remaining organic compounds. In the majority of cases, the nitrate content of melon fruit was below the allowable standards. The lowest quantities of nitrates were accumulated by melon fruit of cv. Oliwin in the control treatment.