الفهرس 
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Abstract
This study was carried out in the greenhouse of Agric. Bot. Dept., Mansoura Univ. to investigate the responses of pea plant to osmoregulators (glycinebetaine at 2000 or 4000 mg/l; thiamine at 25, 50 mg/l and calcium chloride at 2.5 or 5 mM) or plant growth substances (methyl jasmonat 105 or 5x105 M; salicylic acid at 50 or 100 mg/l) under normal or saline conditions (5, 7.5 and 10 dSm1). Hoping to find out the most effective chemicals which helped plant to counteracted the harmful effect of salinity on pea growth and yield as well as root and leaf anatomy. For this purpose, our research composed of three experiments: 1First experiment: The aim of this experiment was conducted to study the effect of osmoregulatore or plant growth substances on seed germination, seedling growth as well as some biochemical aspects under normal or saline condition, in addition root anatomy. 2Second experiments:The following experiments was conducted to study the influence of soaking or spraying pea plants with plant growth substances or osmoregulators , in the same levels mentioned in the first experiment, under normal or saline conditions. 3Third experiment: According to the obtained data of the first and second experiments, the third experiment was conducted mainly to study the influence of chosen material (50 or 100 mg/l salicylic acid, 25 or 50 mg/l thiamine and 2.5 or 5 mM calcium chloride) to compared its methods of treatment (Soaking, spraying, or soaking plus spraying) on alleviating the harmful effect of salinity. The most important results achieved are summarized as follows: 1. Low NaCl salinity level (5 dSm1) increased seed germination percentage, amylolytic and proteolytic activities, seedling and shoot growth, water and relative water content, photosynthetic pigments, reducing sugars, nitrogen, potassium, phosphorous, calcium and magnesium content in addition yield and its components. In the contrast, moderate and high NaCl salinity levels decreased all characters mentioned above. 2. Increasing salinity levels up to 10 dSm1 induced significant increase in electrolyte leakage, total soluble and nonreducing sugars, total free amino acids as well as proline content, sodium, chloride. The ratio between both potassium and calcium to sodium in seedlings and pea shoot and root was decreased with increasing sodium chloride salinity levels. 3. Anatomically, low NaCl salinity level increased markedly the diameter of vascular cylinder in pea root as well as the thickness of midrib region due to increasing the dimension of vascular cylinder. In addition, increasing the thickness of leaflet blade due to an increase thickness of palisade parenchyma in pea leaf. Meanwhile, all anatomical characters were decreased under moderate and high levels. 4. Application of any of osmoregulators or plant growth substances increased all morphological and yield characters as well as the quality of seeds. Anatomically, any of chemicals used helped plant to counteract the harmful effect of salinity of root and leaf anatomy throught increasing the diameter of vascular cylinder in pea root, as well as the thickness of midrib regions, dimension of vascular bundles, and leaf blade as well as palisade parenchyma thickness. 5. Under low NaCl salinity level, application of any of osmoregulators or plant growth substances increased all mentioned characters specially yield and its components as well as seed quality. 6. Applications of any chemicals used increased significantly germination percentage, seedling and shoot growth as well as yield and its component under moderate and high NaCl salinity levels as compared to untreated plants under such salinity levels. In conclusion The results of this study indicate that pea is moderate sensitive to soil salinity. Therefore, it can be grown successfully on soils that are either nonsaline or slight saline (below 5dSm1). Increasing salinity levels above 5 dSm1 caused a highly reduction in pea growth and yield. It could be obtaine a good yield of pea plant cv MasterB under normal or saline condition (above 5 dSm1) by soaking seeds in salicylic acid at 50 mg/l for 6 hours, then spraying the shoot twise with the same concentration after 25 and 35 days from sowing, or soaking seeds only where the differences between the two methods of treatment is low.