Thesis (Ph.D.) - Cairo University - Faculty of Agriculture - Department of Agricultural Botany

The present investigation was conducted to study the effects of humic acid (HA), salicylic acid (SA) and ascorbic acid (AsA) on growth, yield, oil %, fatty acid composition of seed oil and chemical constituents of canola plants grown under three salinity levels (control, 4000 or 8000 ppm). This experiment was carried out in the green house of the plant physiology division, Fac. of agric., Cairo Univ., Giza, Egypt, during two successive seasons; 2014/2015 and 2015/2016. The obtained results confirmed the significant negative effects of salinity on canola growth characters including root length and shoot height, root and shoot fresh and dry weight, total plant leaves area as well as yield components comprised of number of siliquae/plant, number of seeds/siliqua, seed yield/plant, oil % and fatty acids percentage in canola oil. Furthermore, salinity resulted in a significant decrease in chlorophyll a and b, N, P and K concentrations in roots and shoots of canola plants. However, data revealed a progressive increase in Na, free amino acids, free proline, total soluble phenols and total sugar concentrations in roots and shoots. The results indicated the promotive effects of HA (50 or 100 ppm), SA (36 or 72 æM) and AsA (1.5 or 3 mM) on the growth characters and yield components of canola when compared to the control. Application of HA at 100 ppm resulted in the highest root length and shoot height, root and shoot fresh and dry weight, total plant leaves area as well as yield components including number of siliquae/plant, number of seeds/siliqua, seed yield / plant and oil % as compared to the other salinity tolerance inducers or control plants

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