الفهرس 
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Abstract
The objective of this investigation are directed to evaluate the effects of foliar applications of proline, seaweed extract, humic acid, yeast extract and compost tea at different concentrations on various growth, yield and chemical composition of maize plants grown under salt-stress conditions. The second aim was to undertaken to test the efficiency of respective the bio-stimulants and to identify the best suitable concentrations that gives the better response against the salinity stress.
To achieve these objectives, a field experiment was conducted on maize at the Experimental Farm of Agriculture Faculty (Saba-Basha), Alexandria University, Egypt, during the growing season of 2017.The soil of the experiment site was considered moderately saline. Each plot consisted of 5, ridges each 3.5 m in length and 3 m in width, occupying an area of 10.5 m2. The maze kernels (Zea mays, L. cv. Hybrid 3062) were sown during the growing season of 2017. Nitrogen fertilizer at the rate of 46 kg N /fed was added, as urea, in three equal doses after 15, 30, and 45 days after sowing. Phosphorus fertilizer, as calcium superphosphate at the rate of 32 kg P2O5/fed and potassium sulphate at the rate of 25 kg K2O/fed were incorporated with upper soil surface before planting. The bio stimulants treatments were four levels of proline (0, 0.1, 0. 2, and 0.3 ml/l ), compost tea (0, 5, 10, and 15 ml /l ), Humic acid (0, 1, 2, and 3 g /l ), dry yeast (0, 20, 40, and 60 g /l ) and Seaweed extracts (0, 1, 2, and 3 ml/l ) sprayed three times during the growth period. The first dose was applied after 15 days of planting and then every 15 days for the second and third spray. The foliar applications were conducted in early morning. The normal agronomic practices of growing maize were practiced till harvest. The experiment was laid out in randomized complete design with three replications. The result of this experiment could be summarized as follows:
A-Effect of the bio-stimulants treatments on growth and yield of maize
Soil salinity is a serious threat to maize production worldwide. Understanding maize response to salt stress and resistance mechanisms and over viewing management options may help to devise strategies for improved maize performance in saline environments.
1. Growth characters
The effect of bio-stimulation treatment on the vegetative growth characters of hybrid corn plants, in terms of plant height shoot fresh and dry weights per plant were recorded at 50, 65, and 80 days after sowing. The data showed that:
-The maximum plant height (cm) at the respective growth stages was observed with the application of compost tea at 15m/l (112.81, 141.01, and 176.26 cm), followed by humic acid at 3 g/l (110.80, 138.50, and 173.12 cm), as compared with control treatment which recorded the minimum values of plant heights (cm) during 2017 season at the three growth stages respectively.
-The shoot fresh weights were progressively increased upon ageing. Significant variations were detected in shoot fresh on maize plants trated with the different folian applications of the tested bio stimulants. In addition the shoot fresh weight numerically was increased with increasing the concentration of each bio-stimulant, revaling that the maximum shoot fresh weight values (523.73, 654.66 and 818.33 g) were recorded with compost tea at 15 ml/l, followed by humic acid at 3 g/l (518.73, 648.43 and 810.54 g ) and proline at 0.3 g/l (513.26, 641.57and 801.97 g ), at three growth stages during 2017 season respectively
-Similarly the maximum shoot dry weights (104.74, 130.93 and 163.66 g) were recorded with compost tea at 15 ml/l, followed by humic acid at 3 g/l (103.74, 129.68 and 162.10 g), proline at 0.3 g/l (102.65, 128.31 and 161.39) and, yeast at 60 g/l (101.47, 126.84 and 158.55 g) at the three growth stages respectively as compared with control treatments.