Salinity is one of the most devastating environmental factors limiting crop productivity worldwide. Therefore, our study investigates the effect of seed priming with zinc oxide nanoparticles (ZnO NPs: 0, 50, and 100 mg L⁻¹), 24-epibrassinolide (EBL: 0.0, 0.2, and 0.4 µM), and their combined treatments on maize (Zea mays L.) grown with different levels of saline stress (i.e., control, 5, 10 dS m⁻¹) under semi-controlled conditions. Higher saline stress (10 dS m⁻¹) negatively influenced the growth traits, physiological attributes, and elemental (i.e., Zn and K) uptake for both roots and shoots of maize, whereas it increased Na⁺ accumulation and Na⁺/K⁺ ratio in comparison to other treatments. However, seed priming with ZnO NPs and EBL as well as their combinations showed amelioration of the detrimental effects of saline stress on the growth and physiological and biochemical performance of maize. In general, seed priming with combined treatments of ZnO NPs and EBL were significantly more effective than either ZnO NPs or EBL as individual treatments. A combination of 100 mg L⁻¹ ZnO NPS + 0.2 µM EBL resulted in the highest values of root length, root surface area, stem diameter, relative leaf water contents, total chlorophyll, net rate of photosynthesis, zinc accumulation, and K⁺ uptake, while it resulted in the lowest Na⁺ and Na⁺/K⁺ ratio, especially under the highest saline-stress treatment. Thus, we concluded that seed priming with combined ZnO NPs and EBL can effectively mitigate the saline-stress-mediated decline in the morphological, physiological, and biochemical traits of maize.

Salinity is one of the most critical problems for agricultural development and threatens future food safety. Therefore, we aimed to investigate root application of zinc oxide nanoparticles (ZnO-NPs; 0, 50, 100 mg/L), 24-epibrassinolide (EBL; 0, 0.02, 0.04 µM), and their combinations on the growth and performance of maize (Zea mays L.) as a model plant grown under salt stress (i.e., 0, 5 and 10 dS m⁻¹) in a hydroponic system. The results showed that the highest salt stress negatively affected growth, physiological, and biochemical traits of maize. However, the application of EBL, ZnO-NPs, and their combinations significantly mitigated salt stress and improved the growth and performance of the physiological system in maize plants. In particular, the combination treatment of 100 mg/L ZnO-NPs + 0.02 µM EBL surpassed all other root treatments and resulted in the highest root and shoot growth, leaf area, relative leaf water content, net photosynthesis, total chlorophyll content, and uptake of zinc (Zn) and potassium (K). Furthermore, it minimized salt stress by reducing Na uptake, Na/K ratio, and proline in stressed maize plants. For example, the combination treatment of 100 mg/L ZnO-NPs + 0.02 µM EBL improved root length by +175%, shoot length by +39%, leaf area by +181%, RWC by +12%, net photosynthesis by +275, total chlorophyll content by +33%, and total phenolic content by +38%, in comparison to those obtained from the control, respectively. Furthermore, it enhanced the roots and leaves uptake of Zn under high salt stress treatment (i.e., 10 dS m⁻¹) by +125% and +94%, and K⁺ by +39% and +51%, as compared to those grown without any of NPs or EBL treatments, respectively. Thus, the root application of 100 mg/L ZnO-NPs + 0.02 µM EBL can be a potential option to mitigate salt stress and improve the physiological, biochemical, and performance of strategy crops such maize.

Salt stress is one of the most significant abiotic stresses that substantially negatively impact plant growth and productivity. However, a slew of research thus far has investigated the ameliorating properties of arbuscular mycorrhizal (AM) symbiosis and their potential to improve plant tolerance to salt stress. The present study aimed to evaluate and compare the role of mycorrhizal inocula obtained from Sabkha (S-AMF) and non-Sabkha (NS-AMF) habitats of Saudi Arabia on the morphological, physiological, and biochemical behaviors of the Lasiurus scindicus plant. For this reason, arbuscular mycorrhizal fungi (AMF) isolated from Sabkha and non-Sabkha soils were treated with salinity-exposed L. scindicus. The results revealed that the AMF-treated plants had higher growth metrics and increased synthesis of photosynthetic pigments, which were reduced by salt stress. Furthermore, the application of AM symbiosis induced an increase in the activities of the antioxidant system, which resulted in a reduction of the plant oxidative damage. It was also found that the increased accumulation of proline and phenols acted as a protective measure. Moreover, plants inoculated with S-AMF had the highest ameliorating responses on all the studied parameters compared to NS-AMF. This could be attributed to the presence of habitat-specific AMF, which may have induced adaptive plasticity in plants to tolerate or resist extreme salinity. However, further study in exploring the S-AMF diversity is needed to make it an ecofriendly choice for the restoration of salinity-affected ecosystems.

Light emitting diodes (LEDs) are potential light sources for in vitro plant cultures. Here, axillary blackberry shoots were grown in MS medium with indole-3-butyric acid (1 mg L⁻¹), naphthalene acetic acid (0.5 mg L⁻¹), and sucrose supplementation (0–60 g L⁻¹) and the cultures were incubated under four light treatments: three LED light treatments (blue + red light (2:1 spectral ratio), blue + red light (1:2), and cool + warm white light (1:1)) and a standard florescent tube white spectrum treatment. Sucrose was indispensable for rooting of blackberry microshoots. Sucrose concentrations up to 45 g L⁻¹ increased total root length and root surface area under all light treatments. However, at this sucrose concentration, leaf area and vegetative growth were negatively affected. Plantlets grown in media containing 15–30 g L⁻¹ of sucrose exhibited the highest leaf pigments, shoot length, and number of leaves. LED treatments increased leaf pigments as compared with florescent treatment. Plantlets grown under blue + red light (2:1) had the highest stoma aperture length and width, whereas cool + warm white light resulted in the lowest values. Among the LED treatments, blue + red light (2:1) resulted in the highest leaf area, chlorophyll and carotenoid contents, and vegetative growth, whereas fluorescent resulted in the lowest values. A combination of blue and red light at a 2:1 spectral ratio with 30 g L⁻¹ of sucrose is recommended for the optimal in vitro rooting and vegetative growth of blackberry microshoots.

Nicotian glauca is a noxious invasive shrub in Saudi Arabia, and it is well known for its harmful impact on biodiversity, competing with native plants using various strategies. Among their strategies is their allelochemical activity, i.e., the use of chemicals to dominate and compete. The present study aims to evaluate the allelopathic potential of N. glauca aqueous extracts from leaves, flowers, and twigs on Acacia gerrardi seed germination and seedling growth. Petri dishes containing extracts from N. glauca parts with different concentrations were incubated in a growth chamber. The results indicated that extracts and concentrations negatively impact seed germination and hypocotyl. Relative to the control, the leaf extract with concentrations of 60 and 100 g/L reduced the seed germination rate by 81.11% and 93.33%, respectively. Flower extracts of similar concentrations decreased germination by 81.91 and 92.55%, while the twig extracts declined germination by 79.56 and 95.69%, respectively. The leaf, flower, and twig extracts (100 g/L) decreased hypocotyl radicle by 76.54, 78.05, and 65.75%, respectively. Overall, the concentrations of 20, 60, and 100 g/L showed the lowest growth indices. Generally, aqueous extracts, particularly 100 g/L, impacted the germination and protrusion of A. gerrardii hypocotyl. In conclusion, our study draws attention to the harmful impact of N. glauca on A. gerrardii regeneration.

Philodendron bipinnatifidum Schott ex Endl. is a popular ornamental plant that is normally propagated by tissue culture methods. However, the growth and acclimatization of micropropagated plants are tarrying processes. Therefore, in the present study we examined the effect of arbuscular mycorrhizal fungi (AMF) Gigaspora albida and G. marginata on the success in the establishment, growth, and development of P. bipinnatifidum plantlets during the acclimatization phase. AMF plants had significantly more leaves (10.67 per plant), leaf area (75.63 cm²), plant height (14.17 cm), shoot fresh weight (3.30 g) and shoot dry weight (0.31 g), according to an analysis of growth characteristics. In comparison, non-AMF plants had lower values for these metrics. In addition, AMF plants had significantly longer main roots (23 cm), total length roots per plantlet (485.73 cm), average root diameter (4.58 mm) per plantlet, number of root tips (236) per plant, total root surface area (697.76 cm²), total root volume (79.98 cm³), roots fresh weight (1.51 g), roots dry weight (0.16 g) than non-AMF plants. AMF-treated plants showed better performance in leaf gas exchange, chlorophyll, and carotenoid content. These results emphasize the need for mycorrhization of micropropagated plants to promote vegetative growth, especially during the acclimatization stage.