## 2 Materials and Methods  
One-year-old, bare-rooted, decapitated at a height of 15 cm, apple Malling Merton 106 (_Malus domestica_ Borkh. ; MM106) plants were used. All lateral shoots were removed, and the plants were planted in 4 L plastic pots. The experiment was conducted at the Department of Agricultural Development of the Democitus University of Thrace, Orestiada (longitude: 26\({}^{\circ}\)31\({}^{\prime}\), latitude: 41\({}^{\circ}\)29\({}^{\prime}\)), Greece, under natural lighting. There were three substrate mixtures (treatments) derived from the application of different substrate additives in each treatment from the beginning of the experiment. More specifically, the substrate mixtures included: (i) sand + perlite (1:1--control), (ii) sand + perlite + zeolite (1:1:1--zeolite) and (iii) sand + perlite (1:1) + 100 mL compost (effective microorganisms, EM). All plants were irrigated with 0.2 L of Hoagland 50% nutrient solution modified as described by [PERSON] et al. [56] every two days, except those of the treatment with compost and microorganisms. The plants of the treatment in question (3 rd case) were irrigated with water, while every seven days they received 0.2 L of aqueous solution with photosynthetic bacteria, _Saccharomyces_ sp. and lactic acid bacteria (effective microorganisms). Every treatment was divided into four subtreatments: (I) no addition of NaCl, (II) addition of NaCl 50 mM, (III) NaCl 50 mM and seaweed extract spraying solution, and (IV) addition of NaCl 50 mM and ceramic powder (silica (SiO\({}_{2}\)) 80%, alumina (Al\({}_{2}\)O\({}_{3}\)) 20% and fermented by effective microorganisms) spraying. All subtreatments comprised four plant replicates each. The irrigation of the plants with NaCl and the application of the seaweed extract and the ceramic powder solution began 20 days after the establishment of the plants in the pots. Moreover, the plants received distilled water every 15 days to wash away salts. The experiment lasted 76 days until the first severe symptoms of salinity were observed (marginal necrosis of basal leaf blades). At the end of the experiment, the weight of leaf, stem, and root dry matter was measured, while the relative growth rate was calculated based on the initial and finalheight of the plants. Additionally, the chlorophyll was determined in chlorophyll content index (CCI) units (Opti-Sciences, CCM-200, Hudson, NH, USA) in mature top leaves. In order to estimate the leaf concentration of carbohydrates, anthrone (9(10H)-Anthracenone) and sulfuric acid (H\({}_{2}\)SO\({}_{4}\)) were used, according to the [PERSON] [57] method, while the measurement was carried out in a Shimadzu spectrophotometer at 625 nm. The concentration of proline in the leaves was determined by the acidic ninhydrin reaction assay, using the [PERSON] et al. [58] method, and measurements were conducted photometrically at 518 nm. The rate of photosynthesis, the rate of transpiration, the stomatal conductance, and the internal CO\({}_{2}\) concentration in the leaves were determined by a LC Pro+ device (ADC, Biosecientific Ltd., Hertfordshire, UK). Furthermore, phenols were extracted from 0.1 g of leaf fresh matter in 80% methanol, assayed using the Folin-Ciocalteu reagent following the method of [PERSON] et al. (2009); (2010), and expressed as mg of gallic acid equivalents (GAE) per g of leaf fresh weight (FW), which was used for standard curve with a range of 0-125 uM. Flavonoids were extracted from 0.3 g of fresh matter in 80% methanol and determined colorimetrically (2010) with some modifications. Rutin was used as the standard compound for the quantification of total flavonoids. All values were expressed as mg of rutin fresh matter weight (FW). The reported data are the means of four replicates. In order to determine antioxidant capacities in apple plants, two methods were used: (i) 2,2-diphenyl-1-picryl hydrazii (DPPH) (2010) and (ii) ferric reducing antioxidant potential (FRAP) (2011).