No abstract

Two pots experiments were conducted at Abu Hummus,El-Beheira Governorate, Egypt, during the successive winter seasons of 2019 and 2020 to investigate the effect of fulvic acid and silicon in elevating the negative impact of salinity on vegetative growth, yield and chemical composition of spinach under different salinity levels. Each experiment includes 20 treatments which were the combinations between four salinity levels (Tap water, 1500, 3000 and 4500 ppm) and soil application treatments of fulvic (1.5 and 3.0 gm / L) , silicon (1.5 and 3.0 mM) and distilled water as control treatment. The experiments were carried out as randomized complete block design (RCBD) in split plot system with three replicates. Whereas, the salinity levels arranged in the main plots while the soil application treatments of fulvic and silicon were randomly located in the sub-plots. Generally, the obtained results indicated, that all tested characters decreased with increasing salinity levels. The reduction rate on any character varied depending on the imposed level of salinity stress. Adding fulvic acid and silicon in all concentrations showed significant effect in improving all studied traits as compared to the control treatment, in both seasons. Application of silicon at 3 mM recorded the highest values of plant height, plant fresh weight, plant dry weight, number of leaves per plant, nitrogen, phosphorus, potassium, protein and total chlorophyll contents and reduced the hazard effect of nitrate and total oxalate comparing to the other treatments in both seasons. The combined treatment of silicon (Si) at the rate of 3 mM and salinity level at zero gave the highest values of the most tested parameters. The outcome of this research recommends the opportunity of adding silicon (Si) or fulvic acid (FA) to enhance spinach plants and minimize the harmful effect of salinity.

Two pot experiments were carried out under greenhouse conditions during the two successive winter seasons of 2017/2018 and 2018/2019 to enhance the performance of coriander (Coriandrum sativum L.) plants under salt stress conditions (NaCl at 0, 25, 50 and 75 mM). Along with the possibility of enhancing the plant growth, chemical composition, and secondary metabolites of essential oils. Foliar applications of selenium (25 and 50 ppm), nano selenium (25 and 50 ppm), glycine betaine (5 and 10 mM), and distilled water (control treatment) were applied on C. sativum plants. The foliage and root growth, chemical composition, and secondary metabolites of essential oils of coriander plants grown under salt stress were examined. The obtained results of the two seasons revealed that salt stress had significant deleterious effects on vegetative growth, fruit yield, essential oil yield, secondary components, and leaves chemical composition, while it enhanced the electrolyte leakage, proline content, Na + and Clof the leaves. Generally, the tested treatments: selenium, nano selenium, and glycine betaine varied in their significant effects on the studied characters. Selenium and glycine betaine treatments were more effective in improving coriander plants to salinity stress where they significantly increased almost all the studied parameters under saline compared to the control.

Two pots experiments, at two successive winter seasons, were carried out to investigate the effects of two nitrogen (N) sources (ammonium nitrate and urea) and foliar applications of molybdenum (Mo), sucrose (Suc) or selenium (Se) on the growth and quality of the edible parts of spinach (Spinacia oleracea L. cv. Balady). The results indicated that the growth and quality of spinach plants can be greatly determined by the applied N source. The edible parts of spinach plants that received urea as N source showed lower content of NO3-, soluble oxalate, insoluble oxalate and total oxalate plus higher level of P content, however, higher moisture content as well as lower accumulation of dry mass, vitamin C and Fe were also observed in both seasons. Among the tested foliar applications at different concentrations, the treatment with 10% sucrose showed superior effects for increasing spinach growth (increase fresh weight, dry weight and leaves area) and quality (increase the contents of N, P, K, Ca, Fe, total protein and chlorophyll, as well as decreasing the contents of soluble oxalate and total oxalate) relative to the control (distilled water) in both seasons. The interaction treatment of urea fertilizer with foliar application of 10% sucrose was the most efficient one in decreasing NO3and soluble oxalate contents without reductions in growth (fresh and dry weights), the contents of vitamin C and minerals against the corresponding control in both seasons.

Potato (Solanum tuberosum L.) is an important crop in Egypt with great trade value for the export market. The addition of agrochemicals with possibly containing heavy metals, such as cadmium (Cd), decreases the quality of the final product. Generally, little is known about the factors that influence Cd content in this crop. The current study estimated the Cd levels in different organs of three potato cultivars grown in four commercial regions across Egypt. Further, we investigated the soil properties that affected Cd uptake during two growing seasons. With the exception of the Cd content of the soils, no relationships were detected between the tested soil properties (i.e., pH, conductivity, organic matter, and clay content) and Cd content in potato organs, because the soil from different regions showed comparable levels for these parameters. The average Cd content in the peeled tubers among different cultivars (0.145 mg Kg−1 DW) was below the maximum limit (0.5 mg Kg−1 DW). The patterns of Cd accumulation in potato organs were constant among cultivars, with the highest levels detected in leaves (~82%), followed by stems (~16.5%), and the lowest content observed in tubers (~1.5%). The study showed that the tested potato cultivars exhibited diversity in the accumulation levels of Cd in the tubers (~2.6-fold). The cultivar Suntana displayed the lowest Cd levels among different field sites for the two growing seasons, suggesting the potential involvement of genetic factors.