## 4 Discussion  
Salinity reduced strawberry plant growth significantly, as was evident by the reductions of leaflet area, AGPM area, AGPM fresh and dry weights, and root fresh and dry weights. Similar results have been reported for several cultivars, including Camaroosa, by many researchers [4, 35, 36, 37, 38, 39, 40]. According to some researchers [35, 36] salinity slows down leaf development, induces deficiencies in nutrients such as N, P, and K, while at the same time causing chlorophyll content to decrease [40], leaf senescence to accelerate, and inducing toxicity symptoms in the older leaves--all of which symptoms lead to reduced photosynthetic activity, low production of photoassimilates, and thus reduced growth. Furthermore, salinity imposes also osmotic stress, by decreasing the osmotic potential of soil solution, hindering thus the absorption of water needed for growth [38]. [PERSON] et al. [36] reported that salinity affected only the number of leaves and not the leaf area per se, while [PERSON] et al. [39] reported the exact opposite, since the number of leaves remained unaltered while the leaf area was reduced. In the present trial, both these parameters were reduced, which indicates the severity of the salinity stress imposed. Furthermore, [PERSON] et al. [36] reported that the ratio of root-to-shoot dry weight was increased in favor of root growth and this was attributed to the greater reduction of the above-ground biomass, which can be attributed to leaf loss [39]. Similar to these findings, in the present experiment, the reduction of AGPM dry weight was greater than that of roots, indicating that roots are more tolerant to salinity than the leaves [36]. The treatments, to some extent, alleviated the negative impacts of salinity, with different effects on the measured parameters. The BETZ treatment resulted in a similar leaflet area to that of Blank treatment, which did not lead to increased total leaf area--the number of leaves being rather significantly reduced. Figure 9: Principal component analysis scatterplot of the measured variables, based on the treatments imposed. AGPM dry weight was severely reduced under all alleviation treatments, while BETZ was the only treatment in which root dry weight was not reduced significantly, compared with Blank, being at the same time higher than that with Control, as has been reported in other cases too [41]. Both zeolite and bentonite have been found to increase the water-holding capacity of the substrate [41; 42; 43; 44; 45], leading probably to a significant alleviation against low osmotic potential induced by salinity, allowing thus more water to be available for the growth of roots [8; 46]. This could partly justify the increased root fresh weight determined in BETZ compared with Control, as roots may have retained higher water mass, as well as the similar root dry weight to Blank, as reported by others too [47; 48]. This alleviation efficacy of BETZ treatment was not observed in AGPM fresh and dry weights, leading to the assumption that although there was enough water in the roots, it was not transferred to the above-ground parts of the plants. This could be ascribed to restrictions of vessel hydraulic conductivity due to salinity [49] and/or reduced transpiration rate due to malfunction of the stomata, by the increased Na concentration at the expense of the K concentration (antagonistic effect on both uptake and transport) [47; 49; 50], which regulates stomatal aperture and thus photosynthesis and growth. The microbial treatment (BA) was less effective than BETZ in most cases, although the same bacillus (not necessarily the same strain though) has been found to induce salinity tolerance to many crops, by increasing the fresh and/or dry weight of the plant [51], its growth and yield [52; 53]. The discrepancies found here could be attributed to the different strains used, to the different growth conditions, salt concentration, and applications used.