## 4 Discussion
Zeolite application has been reported to reduce leaf senescence in salinity-stressed sorrel plants by increasing leaf chlorophyll content and reducing its degradation [92]. The implementation of zeolite can also indirectly enhance the photosynthetic rate of stressed plants, as it improves water and nutrient availability owing to its high adsorption capacity [93]. In our study, zeolite did not seem to have any positive effect on shoot and root DW, carotenoid concentration, photosynthetic parameters, and carbohydrate and flavonoid concentrations under saline conditions. The application of compost combined with the administration of effective microorganisms contributed to a higher root DW, transpiration rate, carotenoid concentration, and antioxidant capacity compared with the control under normal conditions. Previous research has shown that LAB, as biofertilizers, can improve nutrient availability from compost and other organic material, while PGPB increase nutrient uptake and plant biomass production [94]. Most composts are presumed to provide a \"warm\" growing medium, which promotes root growth [95]. Several previous studies have shown that inoculation with photosynthetic bacteria can increase plant production [96]. Purple non-sulfur bacteria (PNSB), a major group of photosynthetic bacteria containing _Rhodospseudomonas_ spp. and _Rhodobacter_ spp. [97], are able to transform atmospheric molecular nitrogen into ammonia (NH\({}_{3}\)) or ammonium (NH\({}_{4}\)+) with a specific nitrogenase enzyme, thereby making this nitrogen available for absorption by plants [98; 99]. Furthermore, PNSB has been reported to improve the nitrogen use efficiency of plants [100]. At the same time, the EM treatment apple plants grown in the presence of salinity showed higher leaf DW, proline concentration, concentration of phenolic compounds, and antioxidant capacity assessed with the DPPH method compared with the corresponding control plants, while the combination of compost and effective microorganisms did not appear to induce a significant increase in shoot and root DW, relative height growth rate, and carotenoid, carbohydrate, and flavonoid concentrations, and photosynthetic parameters of plants exposed to NaCl. Plant biostimulants are considered as one of the most promising and efficient strategies for maintaining yield stability [101]. In this context, many PNSBs, such as _Rhodospseudomonas_ _plastris_, _Rhodobacter__shareoides_, and _Rhodowulum_ spp. have been identified as potential 5-aminolevulinic acid (5-ALA) producers [102; 103; 104], which is abundant in bacteria, algae, plants, and constitutes a plant growth regulator and confers tolerance to plants of various abiotic stresses [105]. On account of the additional nutrient release from the disintegrating organic components, the resistance to abiotic stresses could be amplified with the use of organic ingredients in growing media [95]. Moreover, it has been noted that LAB, as biostimulants, are in a position to directly promote the alleviation of various abiotic stresses [28]. Several strains of plant-growth-promoting bacteria, such as _Burkholderia_[106], _Arttbroacter_, and _Bacillus_[107] amplify proline synthesis in stressed plants, which conduces to preserving the cell water status, contributing in this way to the plant coping with the saline conditions [108]. The stabilization of the cell environment, as far as pH is concerned, and the maintenance of antioxidant activity through the removal of reactive oxygen species (ROS) by proline, could improve the activity of various enzymes [109]. Spraying plants with algal extract under salinity generally favored leaf dry matter weight, relative plant growth rate, internal CO\({}_{2}\) concentration, and phenolic concentration. On the grounds that liquid fertilizers deriving from seaweeds through the extraction method exhibit a high content of organic matter, micro and macroelements, vitamins, fatty acids, and growth regulators, they are found to be superior to chemical fertilizers [110].