Effect of nitrogen and some antioxidants on tuberose production

The study was a trial to investigate the effect of different levels of nitrogen (zero, 0.9 and 1.8 g/plant), sprays of different concentrations of two antioxidants materials (ascorbic acid at zero, 125 and 250 ppm and diphenylamine at zero, 100 and 200 ppm were used four times) and their combinations (27 treatments) on the vegetative growth, flowering, corms production and some chemical analysis of tuberose (Polianthes tuberosa L.) cv. Double plants. Results revealed that using nitrogen alone at 0.9-1.8 g/plant/season gave the maximum values of number of leaves / plant and corms diameter. Also, adding nitrogen at 1.8 g/plant combined with ascorbic acid at 125-250 ppm gave the maximum values of dry weight of leaves/plant and of the essential oil percentage in the flowers. Besides, using nitrogen (1.8 g/plant) combined with diphenylamine at 100-200 ppm led to obtain the maximum values of leaves area/plant and cormels number/plant. On the other hand, adding ascorbic. acid at 250 ppm combined with diphenylamine at 100 ppm gave the tallest and earliest lowering plants and the maximum number of flowers per spike. Furthermore, using the three factors together (0.9-1.8 g nitrogen, 125-250 ppm ascorbic acid and 100-200 ppm diphenylamine) gave the maximum values of rachis length, dry weight of flowers/spike, flowering period, corms dry weight, leaves total chlorophyll, and percentage of carbohydrate and nitrogen of the new corms. It can be generally, recommended to treat the tuberose plants with nitrogen at 1.8 gtplant1season and spraying their foliage four times at vegetative growth period with ascorbic acid at 250 ppm and diphenylamine at 100-200 ppm to give good improvements of the vegetative growth, flowering characteristics, corms production and essential oil percentage of tuberose.