Global climate change is a significant challenge that will significantly lower crop yield and staple grain quality. The present investigation was conducted to assess the effects of the foliar application of either Si (1.5 mM) or Si nanoparticles (1.66 mM) on the yield and grain quality attributes of two wheat genotypes (Triticum aestivum L.), cv. Shandweel 1 and cv. Gemmeiza 9, planted at normal sowing date and late sowing date (heat stress). Si and Si nanoparticles markedly mitigated the observed decline in yield and reduced the heat stress intensity index value at late sowing dates, and improved yield quality via the decreased level of protein, particularly glutenin, as well as the lowered activity of α-amylase in wheat grains, which is considered a step in improving grain quality. Moreover, Si and nanoSi significantly increased the oil absorption capacity (OAC) of the flour of stressed wheat grains. In addition, both silicon and nanosilicon provoked an increase in cellulose, pectin, total phenols, flavonoid, oxalic acid, total antioxidant power, starch and soluble protein contents, as well as Ca and K levels, in heat-stressed wheat straw, concomitant with a decrease in lignin and phytic acid contents. In conclusion, the pronounced positive effects associated with improving yield quantity and quality were observed in stressed Si-treated wheat compared with Si nanoparticle-treated ones, particularly in cv. Gemmeiza 9.

The traditional medicinal Ammi visnaga L. plants can be considered as an important economic source of raw materials for the drug industry. Nowadays, increasing the drug raw materials by using safe and favourable treatments is an important issue. So searching for the proper concentration of the suitable bioregulators which achieving high growth rate and enhancing chemical constituents of A. visnaga plants is the goal of this investigation. Foliar application of different concentrations of eitheramino acids (tyrosine and phenylalanine) and phenolic acids (trans-cinnamic acid, benzoic acid and salicylic acid) displayed significant positive effects on the accumulation of chemical constituents including phenolic compounds, flavonoids and total furanochromones in A. visnaga L. Moreover, the high-performance liquid chromatography analysis showed that some phenolic acids are highly increased, decreased or disappear in A. visnaga plants treated with various concentrations of amino acids and phenolic compounds as being compared with untreated control plants. Ferulic acid, cinnamic acid, coumaric acid and P-hydroxy benzoic acid are the most dominant phenolics in Ammi plants. Phenolics are more effective in stimulating the accumulation of phenols, flavonoids, chromones and consequently the scavenging capacity compared with the investigated aromatic amino acids. Such stimulatory effects are positively related to the applied investigated concentrations of the applied bioregulators. Indeed, Ammi plants treated with phenolics particularly benzoic acid (20 mg L⁻¹) exhibited the greatest accumulated levels of phenolics and chromones there by enhancing thee conomic source of raw materials for drug industry.

Now days, production of fuels and petrochemicals from renewable lignocellulosic biomass is an indispensable issue to meet the growing energy demand. Meanwhile, the changes in the climate and soil topography influence the growth and development as well as canopy level of the lignocellulosic biomass. In this study, Zilla spinosa Turr (Zilla) plants with similar age and size were collected from three main sectors (upstream, midstream, and downstream) of Wadi Hagul during spring (April) and summer (July) seasons. Environmental stresses evoked reduction in the energy trapping pigments concomitant with increments in chlorophyll fluorescence in summer harvested plants particularly at downstream. Furthermore, the biofuels generating compounds including carbohydrate, lignin, and lipid making the plant biomasses are greatly affected by environmental conditions. Greater amount of lignin was estimated in summer harvested Z. spinosa shoots particularly at downstream. Moreover, the total oil content which is a promising source of biodiesel was considerably decreased during summer season particularly at downstream. The physical properties of the lipids major constituent fatty acid methyl esters determine the biofuel properties and contribute in the adaptation of plants against environmental stresses. Hence, the analysis of fatty acid profile showed significant modifications under combined drought and heat stress displayed in the summer season. The maximum increase in saturated fatty acid levels including tridecanoic acid (C13:0), pentadeanoic acid (C15:0), palmitic acid (C16:0), and stearic acid (C18:0) were estimated in spring harvested Z. spinosa aerial portions particularly at midstream. In spite of the reduction in the total oil content, a marked increase in the value of unsaturated to saturated fatty acids ratio and thereby the unsaturation index were achieved during the dry summer period. Henceforth, these seasonal and spatial variations in fatty acids profiles may contribute in the acclimatization of Z. spinosa plants to soil water scarcity associated with heat stress experienced during summer. In addition, the alterations in the fatty acid profiles may match biofuel requirements. In conclusion, the most adequate growing season (spring) will be decisive for achieving high lipid productivity associated with improved biofuel quality in terms of high saturated fatty acids percentage that improves its cetane number. However, the dry summer season enhanced the accumulation of greater amount of lignin that may enhance the biodiesel quantity.