Water shortage is a major problem limiting the expansion of green areas and landscapes. Using seawater as an alternative source of potable water is not a novel idea, but the issue of salt stress needs to be resolved. Salinity has a negative impact on growth and the aesthetic value of ornamental plants. In order to overcome these challenges, Lathyrus odoratus seeds were hydro-primed and halo-primed with silicon (Si) and silicon nanoparticles (SiNPs), and exposed to seawater levels. Seawater markedly reduced seed germination and growth of Lathyrus seedlings, but halo-priming was shown to significantly alleviate its negative effects. Broadly, SiNPs increased the germination percentage, reduced photosynthetic pigments and carbohydrates decrease, and enhanced water relations, despite having a negative effect on germination speed. Halo-priming significantly increased the proline content and the activities of certain enzymatic (SOD, APX and CAT) and nonenzymatic (phenolic and flavonoids) compounds, that positively influenced oxidative stress (lower MDA and H₂O₂ accumulation), resulting in seedlings with more salt stress tolerance. Halo-priming with Si or SiNPs enhanced the Si and K⁺ contents, and K⁺/Na⁺ ratio, associated with a reduction in Na⁺ accumulation. Generally, halo-priming with Si or SiNPs increased Lathyrus seedlings salt stress tolerance, which was confirmed using seawater treatments via improving germination percentage, seedlings growth and activation of the antioxidant machinery, which detoxifies reactive oxygen species (ROS).

Salinity is linked to poor plant growth and a reduction in global food output. Therefore, there is an essential need for plant adaptation and mitigation of salinity stress conditions. Plants combat salinity stress influences by promoting a set of physiological, biochemical, and molecular actions. Tremendous mechanisms are being applied to induce plant stress tolerance, involving amino acid application. For evaluating the growth and productivity of Moringa oleifera trees grown under salt stress conditions, moringa has been cultivated under different levels of salinity and subjected to a foliar spray of proline (Pro) and phenylalanine (Phe) amino acids. Moringa plants positively responded to the lowest level of salinity as the leaves, inflorescences, seeds, and oil yields have been increased, but the growth and productivity slightly declined with increasing salinity levels after that. However, Pro and Phe applications significantly ameliorate these effects, particularly, Pro-treatments which decelerated chlorophyll and protein degradation and enhanced vitamin C, polyphenols, and antioxidant activity. A slight reduction in mineral content was observed under the high levels of salinity. Higher osmoprotectants (proline, protein, and total soluble sugars) content was given following Pro treatment in salted and unsalted plants. A significant reduction in oil yield was obtained as affected by salinity stress. Additionally, salinity exhibited a reduction in oleic acid (C18:1), linoleic (C18:2), and linolenic (C18:3) acids, and an increase in stearic (C18:0), palmitic (C16:0), eicosenoic (C20:2), and behenic (C22:0) acids. Generally, Pro and Phe treatments overcome the harmful effects of salinity in moringa trees by stimulating the osmoprotectants, polyphenols, and antioxidant activity, causing higher dry matter accumulation and better defense against salinity stress.

A shortages of soil nutrients resources and a lack of accessibility to them especially in calcareous soil are considered some of the main factors that limit plant production. In particular, the cultivation of the Moringa oleifera trees in this type of soil is of special interest given the increasing demand for every part of this tree. Several studies have focused on the production of its leaves as an herbaceous plant and not as a tree, but there has not been extensive research on its pods, seeds, and fixed oil production. In this sense, in this study, we provide an assessment of the use of fertilizers, vermicompost and NPK (as traditional minerals and as nanoparticles), in order to improve pods, seeds, and fixed oil contents, as indicators of the quality of the production of the Moringa oleifera trees in calcareous soil conditions. In this experiment, it was observed that all parameters and the yield of pods, seeds, and fixed oil of the Moringa oleifera tree were significantly improved by increasing the level of vermicompost and using NPK fertilization and combination treatments in both seasons of the study. The combination treatments of 10 and 20 ton ha⁻¹ vermicompost plus NPK control produced the highest percentage of oleic acid with insignificant differences between them.

Prickly pear plant is widely cultivated in arid and semi-arid climates. Its fruits are rich in polyphenols, proteins, vitamin C, minerals, fatty acids, and amino acids. The oil extracted from the seeds also has a significant proportion of linoleic acid (ω6) and might be employed as a therapeutic raw material. The potential of enhancing fruit yield, increasing bioactive compounds of the fruit pulp, and improving the unsaturated fatty acid content of prickly pear oilseed by using the foliar application of brassinolide as a plant growth regulator was the main goal of this study. Prickly pear plants were foliar sprayed with a brassinolide solution at concentrations of 0, 1, 3, and 5 mg L⁻¹. The plant performance was significantly improved following brassinolide applications, as compared with untreated plants. The plants subjected to 5 mg L⁻¹ application exhibited 183 and 188% stimulation in the fruit yield, and 167 and 172% in the seed yield for the first and second seasons, respectively. The highest concentration of phenolic, flavonoid, protein, vitamin C, and maximum antioxidant activity in the fruit pulp was observed following 5 mg L⁻¹ brassinolide treatment. The oil yield has been increased by 366 and 353% following brassinolide at a 5 mg L⁻¹ level over control plants. Linoleic, oleic, and palmitic acids are the major components in prickly pear seed oil. Brassinolide foliar spraying induced an alternation in the fatty acid profile, as linoleic and oleic acids exhibited 5 and 4% higher following 5 mg L⁻¹ application as compared with untreated plants. In conclusion, the treatment of 5 mg L⁻¹ brassinolide improved the growth and quality of prickly pear plants by boosting fruit and seed yields, increasing active component content in the fruit pulp, improving mineral content, and increasing oil production and linoleic acid proportion.

One of the main issues limiting plant productivity is a lack of soil nutrient resources, especially in calcareous soil, which covers more than one third of the world’s land surface area. On the other hand, despite rising demand for all parts of the Moringa oleifera tree, several studies have focused on its leaf production as an herbaceous plant, rather than as a tree, and no extensive research has been carried out on leaf and inflorescence production in the mature tree. As a result, the influence of vermicompost and NPK (minerals and nanoparticles), as well as their combination, under calcareous soil conditions, was investigated in this study. The experiment was set up as a split plot in Randomized Complete Block Design (RCBD) with three replicates. In both seasons considered in this study, it was discovered that increasing the quantity of vermicompost and employing NPK fertilization, as well as their combination treatments, greatly enhanced all parameters and yield of distinct Moringa oleifera tree parts. Furthermore, the combination treatment T21 yielded the highest mean values of growth, leaves, and chemical composition parameters, as well as the highest yield from the Moringa oleifera tree. In both seasons, the highest number of inflorescences per tree, as well as the yield of fresh and dry inflorescences, was measured using combination treatment T18. In both seasons, however, increasing the level of vermicompost, NPK, and their combination treatments significantly reduced the total phenolic and flavonoid content and antioxidant activity of dry Moringa oleifera leaves.

Jojoba seeds have a unique storage lipid wax which is suitable as a basic feedstock in the chemical industry. For saving both human health and the environment, there is a continuous need to search for alternative safe natural sources of plant nutrients. Therefore, in this study the effect of mycorrhizal fungi and Moringa oleifera leaves extract on growth, flowering, fruits set, yield and the chemical composition of the jojoba shrub was studied. The application of a combination of treatments of 20 g L⁻¹ mycorrhizal fungi plus 30 g L⁻¹Moringa oleifera leaves extract recorded the maximum mean values of main branch length, length of secondary branches, number of branched nodes, number of secondary branches, flowering percentage, final fruit set percentage, seeds yield per shrub and per hectare, percentage of minerals, proteins as well as oil yield per shrub and per hectare, chlorophyll a and b, N, P, K percentage with a minimum mean value of the number of days until full bloom in both seasons. The maximum percentage of Gadoleic fatty acid was found with the combination treatment of uninoculation plus 10 g L⁻¹Moringa oleifera leaves extract.