Effect of ascorbic acid and riboflavin on growth of tecoma and duranta plants under stress conditions / Ahmed Shafik Ibrahim Abdelaal ; Supervised Mona Ahmed Darwish , Rania Mohamed Abdelaziz Nassar , Nahed Galal Abdelaziz

Thesis (Ph.D.) - Cairo University - Faculty of Agriculture - Department of Ornamental Horticulture

Duranta erecta: (1st) :The results showed that the non saline water gave the highest values of all growth parameters except number of leaves, root length which increased when plants were treated with 2000 ppm. The same treatment increased the chemical constituents except N% in leaves and roots, P% in leaves and K% in leaves and roots, carbohydrates in branches.Application of ascorbic acid at 400 ppm gave the highest values of the most case of growth parameters and chemical constituents. The interaction between salinity and ascorbic acid, showed that, application of ascorbic acid at 400 ppm under non-saline water followed by 400 ppm ascorbic acid combined with 2000 ppm salinity gave the highest values of growth parameters and chemical constituents in both seasons. The concentration of 8000 ppm salinity produced thinner leaves. Application of ascorbic acid at 400 ppm; on plants grown under salinity stress of 8000 ppm increased midvein length, midvein width, number of xylem rows, midvein bundle and vessel diameter.(2nd) :The results showed that irrigation intervals at 3 days gave the highest values of all growth parameters except root length, fresh and dry weight of roots which increased when plants were treated with irrigation intervals at 7 days. The same treatment increased the chemical constituents except P% in leaves which incresed when plants treated every 5 days. Application of riboflavin at 2000 ppm gave the highest values of the most growth parameters and chemical constituents. The application of riboflavin at 2000 ppm under irrigation intervals at 3 days gave the highest values of growth parameters and chemical constituents in both seasons .Tecoma capensis :(3rd): The results showed that the non saline water gave the highest values of all growth parameters and chemical constituents. Application of riboflavin at 2000 ppm gave the highest values of the most growth parameters and chemical constituents. Followed by application of riboflavin at 1000 ppm

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