Among major constraints to crop production, salt stress affects the morphological structure and yield in crop plants. Nano-fertilizers, have made their hierarchy to supplement the traditional fertilizers in mitigating the effect of abiotic stress due to their slow release and efficiency. Three products were tested namely lithovit®-standard(LITHO), monopotassium-phosphate(MKP:0-52-34), and aspirin(ASP) on salt-stressed tomato crop. These products were applied through foliar spraying (foliar) or fertigation (ferti) on tomato plants irrigated with 4 saline solutions (4, 6, 8 and 10dS/m). Control plants were subjected to five salinity levels (0, 4, 6, 8 and 10dS/m) without any treatments. Results showed that increasing in salinity levels adversely affected all parameters in the control plants. The ameliorating effect of MKP-ferti was prominent in plant height, stem diameter, number of fruits, fruit weight and yield/plant at 4 and 6S/m. Whereas, the effect of salinity was mitigated by LITHO-foliar regarding flowers number and total chlorophyll content at all salinity level. Leaf N, P and K contents were accumulated higher when MKP-ferti was used whereas, Ca²⁺ and Mg²⁺ contents were accumulated higher in the plants treated with LITHO-foliar. The cellular leakage of electrolyte was reduced at 4, 6 and 10dS/m with MKP-ferti and at 8dS/m with LITHO-foliar application. Among the two methods of application, foliar spraying of LITHO and ASP, and fertigation of MKP improved plant performance more than their complementary methods of application. The better performance of MKP necessitates the use of phosphorous and potassium-based nano-fertilizers. It can reduce the production cost of vegetables using conventional fertilizers.

The study of morpho-anatomical aspects, metabolic changes of proteins, antioxidant substances, as well as phenolic compounds in embryogenic callus (EC) and degenerative embryogenic callus (DEC) was the aim of the present investigation. Ability to form somatic embryos (SEs) was associated with the softness of the EC, which exhibited a white or creamy color and was composed of isodiametric cells containing dense cytoplasm, conspicuous nuclei and minimal vacuoles with observed mitotic activity. Furthermore, protein, reduced glutathione (GSH) and ascorbic acid (ASC) concentrations and the ratio between ASC and dehydroascorborbic acid (DHA) were increased significantly in the EC in comparison to the DEC. In addition, the phenolic extract of the EC was proved to have higher scavenging activity than the extract from the DEC. A loss of embryogenic competence in the DEC was correlated with the presence of more rigid clumps and such calli had a yellowish to brown color and no cell division could be observed in the cells of such aggregates as the cells had large vacuoles and they have very thick walls. Moreover, these morphological and anatomical observations of the DEC were accompanied by accumulations of the oxidized form of ascorbic acid (DHA), H₂O_2, total soluble phenolic compounds and overaccumulation of naringenin. Alternations in cellular metabolism can affect and regulate the morphogenesis of somatic embryos.

Lebanon’s land mostly consists of carbonate rocks, which are generally calcareous. Calcium carbonate is not easily penetrable by vine roots except via cracks. Farmers resorted to the application of the conventional chemical calcium fertilizer. The study compared the effect of a conventional Ca fertilizer to two organic Lithovit Nano-Ca fertilizers on “Tfiefihi” variety. These products were applied once or twice. Shoot length, leaf number and composition, berry characteristics, and production indicators were investigated for two consecutive years. The highest shoot length was induced by the two-time application of Lithovit standard (T6) (346.70 cm). One-time application of Lithovit Amino25 (T3) recorded the highest leaf number (206 leaves). One-time application of Lithovit standard (T5) increased phosphorus in leaves by 0.04%. The lowest sugar content at harvest was detected in T5 and the highest one in T6. The two-time application of Lithovit Amino25 (T4) caused the highest delay in veraison (26 d). T3 recorded the highest acidity content in berry (3.83%). Nano-fertilizer has hastened harvest by around 25 d compared to conventional Ca fertilizer. T3 significantly reduced the cluster weight compared to all treatments and reduced the yield. Lithovit standard could be a beneficial substitution to the conventional fertilizer especially when applied twice. Graphical abstract