Physiological and Biochemical Effects of Some Bioregulators on Growth, Productivity and Quality of Artichoke (Cynara Scolymus L.) Plant

Field experiments were conducted during the two successive seasons of 2007 and 2008 in a private farm at Kom El-Berka, Kafr El-Dawar, Behaira governorate, Egypt to study the effect of different concentrations of putrescine (50, 100 and 200 mg/l), gibberellic acid (50, 100 and 200 mg/l) and salicylic acid (100, 200 and 400 mg/l) on vegetative growth, photosynthetic pigments, early yield, productivity and some biochemical constituents of artichoke plant (Cynara scolymus L.) cv. Herious. The results obtained showed that except for the highest concentration of salicylic acid (400 mg/l) all concentrations of the applied bioregulators tend to increase vegetative growth parameters i.e. plant height, number of leaves, fresh weight of 4th leaf as well as dry matter accumulation. The highest effect was obtained by putrescine (50 mg/l), gibberellic acid (100 mg/l) or salicylic acid (100 mg/l). Flowering aspects of artichoke plant were positively stimulated by foliar spray of the above mentioned bioregulators accompanied by parallel increase in photosynthetic pigments and acceleration in early yield and plant productivity. The stimulatory effect was contrary proportional with bioregulators concentration in most cases. The lower concentration of salicylic acid (100 mg/l) was more effective in accelerating earlier yield while the heaviest late yield was recorded by putrescine at 50 mg/l. With exception of SA treated plants, bio-regulators treated plants contained more mineral content ( N, P, K, Mg and Fe), total free amino acids, ascorbic acid content as well as endogenous phytohormone promoters (IAA, gibberellic acid and cytokinin) and less endogenous phytohormone inhibitor (ABA).