Two successive field trials were carried out at the experimental farm of the Agriculture Department of Fayoum University, Fayoum, Egypt, to investigate the sole or dual interaction effect of applying a foliar spray of Aloe saponaria extract (Ae) or potassium silicate (KSi) on reducing the stressful salinity impacts on the development, yield, and features of roselle (Hibiscus sabdariffa L.) plants. Both Ae or KSi were used at three rates: 0% (0 cm3 L−1), 0.5% (5 cm3 L−1), and 1% (10 cm3 L−1) and 0, 30, and 60 g L−1, respectively. Three rates of salinity, measured by the electrical conductivity of a saturated soil extract (ECe), were also used: normal soil (ECe < 4 dS/cm2) (S1); moderately-saline soil (ECe: 4–8 dS/cm2) (S2); and highly-saline soil (ECe: 8–16 dS/cm2) (S3). The lowest level of salinity yielded the highest levels of all traits except for pH, chloride, and sodium. Ae at 0.5% increased the values of total soluble sugars, total free amino acids, potassium, anthocyanin, a single-photon avalanche diode, stem diameter, fruit number, and fresh weight, whereas 1% of Ae resulted in the highest plant height, chlorophyll fluorescence (Fv/Fm), performance index, relative water content, membrane stability index, proline, total soluble sugars, and acidity. KSi either at 30 or 60 g L−1 greatly increased these abovementioned attributes. Fruit number and fruit fresh weight per plant also increased significantly with the combination of Ae at 1% and KSi at 30 g L−1 under normal soil conditions.

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This study aimed to determine the effects of compost amendment on the soil properties, as well as the morphophysiological responses, seed yield, oil content, and fatty-acid profile. of Nigella sativa plants under drought stress conditions. In a split-plot design, the field experiment was carried out during two seasons (2020/2021 and 2021/2022), involving three irrigation regimes (named I100, I75, and I50 of crop evapotranspiration) with three levels of compost application (C0, C15, and C30). Soil porosity, permeability, pore geometry, water-holding capacity, organic content, and soil cation exchangeable capacity were improved in response to applied compost levels. The growth, physiology, biochemistry, and yield characteristics of Nigella sativa plants were positively affected by compost addition but negatively affected by increasing water stress severity. Deficit irrigation regimes increased osmoprotectant substances (i.e., proline, total free amino acids, carbohydrates, and total soluble sugar). Compared to the control (I100), deficit irrigation (I50) reduced fixed and essential oil by 16.64% and 39.57% over two seasons. Water stress increased the content of saturated fatty acids, while unsaturated fatty acids decreased. Compost application of (C30) resulted in a significant increase in seed yield, fixed oil, and essential oil of Nigella sativa plants by 34.72%, 46.55%, and 58.11% respectively, compared to the control (C0). Therefore, this study concluded that compost amendment improved soil properties and significantly mitigated the detrimental effects of drought on Nigella sativa plants, resulting in a considerable increase in seed yield and its oil content, particularly polyunsaturated fatty acids, which are distinguished by their beneficial effects on human health.

This study was carried out on coffee plants (Coffea arabica L.) during 2009/2010 season. This work was conducted to investigate the effect of different MS medium strengths (Full, ¾ and ½ strength) in starting stage on survival percentage of shoot tip explants, and the effect of different concentrations of benzyl adenine (2.0, 4.0 and 6.0 mg/l) and kinetin (2.0, 4.0 and 6.0 mg/l) on proliferation rate (shoot length, no. of shoots and leaves). In addition to study the effect of different IBA concentrations (1.0, 2.0 and 3.0 mg/L) on rooting (roots no. and length) and growth improvement (plantlets length and leaves no./ plantlets) of coffee plantlets. Also, Plantlets were acclimatized in acclimatization stage for 3 months in different growing media including sand, peat moss, sand : peat moss at 1:1 v/v and sand : peat moss at 1:2 v/v for producing good coffee offshoots. At starting and multiplication stages, significant differences were observed on survival % of explants and proliferation rate as affected by different MS medium strengths and BA or Kinetin treatments. Full strength of MS Medium supplemented with 6 mg/L BA or 6 mg/L kinetin gave the best significant result for survival % of explants and multiplication rate (shoot length, no. of shoots and leaves). At rooting stage, half strength MS medium with IBA (3 mg/L) gave the best significant result for coffee plantlets growth and root formation (length of plantlets and roots and no. of leaves and roots /plantlet). Thereafter, coffee Plantlets were hardened for 3 months during acclimatization stage and found that the growing media including sand : peat moss at 1:2 v/v recorded the best parameters measured in this stage.

Background There is a growing body of literature that recognizes the importance of natural biostimulants in the agricultural productivity. This potential can play an important role in addressing the issue of cultivation of sandy soil, which is well-known with soil nutrient deficiency stress. In the current study, the selected biostimulants (i.e., chitosan, amino acids, yeast extract, and humic acid) were foliar applied on green bean in the open field of alkaline sandy soils. Results The main results that obtained after harvesting the fresh green bean pods were confirmed that all studied biostimulants improved the quantity and quality of green bean production compared to the control. Chitosan was the best applied biostimulants for producing green bean in a lower fiber and nitrate content in pods, a higher crude protein content in pods, and higher NPK content in leaves. Conclusion The role of studies biostimulants in promoting green bean productivity under nutrient deficiency stress may back to increase the uptake of nutrients (NPK), plant physiological (higher dry matter) and biochemical attributes (higher crude protein). More studies are needed using different applied doses and more different kinds of natural biostimulants.