## 3 Results and Discussion  
### Effect of Biostimulant Application on Growth Parameters of Snap Bean  
The data in Table 5 show that foliar application of biostimulants significantly enhanced all tested growth parameters, i.e., the height of the plant, number of leaves and branches/plant, total fresh and dry weight of leaves and stems, and the diameter of stems, of treated snap bean plants compared to the untreated plants in both seasons. The maximum plant height, number of leaves and branches/plant, total fresh and dry weights of leaves and stems, and diameter of the stem were 82.33 and 84.56 (cm), 22.11 and 24.11, 6.11 and 7.00, 133.44 and 157.89 (g), 25.39 and 31.14 (g), and 1.07 and 1.10 (cm) in the 2018 and 2019 seasons, respectively. These variances were the result of a foliar spray of moringa extract. The minimum plant height, number of leaves and branches/plant, total fresh and dry weights of leaves and stems, and stem diameter were 60.44 and 65.33 (cm), 13.67 and 14.56, 3.78 and 3.89, 91.11 and 92.89 (g), 16.46 and 18.71 (g), and 0.78 and 0.79 (cm) in the 2018 and 2019 seasons, respectively, in the control treatment. The maximum plant height, the number of leaves and branches/plant, total fresh and dry weights of leaves and stems, and diameter of the stem were 76.78 and 78.44 (cm), 19.11 and 21.33, 4.44 and 5.00, 114.11 and 118.56 (g), 23.17 and 23.05 (g), and 0.88 and 0.90 (cm) in 2018 and 2019, respectively, in plants treated with a foliar spray of humic acid with statistical variance, followed by yeast extract treatment, the values of which were 73.67 and 74.44 (cm), 16.78 and 17.44, 3.89 and 4.44, 103.89 and 106.89 (g), 17.14 and 22.45 (g), and 0.87 and 0.88 (cm) in 2018 and 2019, respectively. It should be noted that the effect of humic acid on plant growth is attributed to its supply of growth hormones. This was confirmed by [PERSON] et al. [42], who reported that humic acid contains gibberellins, auxins, a higher quantity of phenolic compounds, and a large amount of acids. [PERSON] et al. [43] studied the influence of foliar spraying of humic acid (2000 mL/L) on common bean plants, and they found that humic acid contributed to a significant increase in plant height. It was also proven that the addition of foliar humic acid at 1, 2, or 3 g/L significantly affected all vegetative growth parameters (plant height, number of leaves and branches, and fresh and dry weight) of whole snap bean plants cv. Paulista grown under sandy soil conditions compared with the control plants [44]. Additionally, yeast extract contains vitamins, especially B-complex, enzymes, and phytohormes, such as auxins and cytokines [45; 46]. The improvement of some vegetable crop attributes with the application of yeast extract was reported by previous studies [47; 48; 49; 50] on the flowering characteristics of cucumber, as well as on melon growth [51]. Furthermore, the advantages of spraying yeast on flowering characteristics could be due to its essential bioconstituents, i.e., carbohydrates, protein, hormones (GAs, IAA, and cytokines), minerals, and vitamins, particularly B-complex, which affects physiological and biochemical processes in plants such as ion uptake, cell division, and elongation, as well as hormonal and enzymatic activities, which are reflected in the induction of growth and flowering ([45; 51]). As shown in Table 2, the enhancement of the growth characteristics of plants treated with MLE is due to its high content of growth-promoting hormones (i.e., auxins, gibberellins, and cytokins). In general, these hormones act as catalysts for plant growth and play a regulatory role in the physiological relationships between different plant organs [52]. In particular, auxins regulate cell elongation and promote stem growth, lateral root formation, and fruit development, while gibberellins regulate plant height, and cytokins regulate cell division [53]. The increase in the number of branches and plant differentiation may be due to increased cell division and cell elongation in axillary buds [54].