Response of growth, flowering and some biochemical constituents of Calendula officinalis L. to foliar application of salicylic acid, ascorbic acid and thiamine

A pot experiment was conducted to evaluate the effect of foliar spray of salicylic acid (0, 50, 100 ppm), ascorbic acid (0, 100, 200 ppm) and thiamine (0, 50, 100 ppm) on vegetative growth, flowering and photosynthetic pigments of marigold (Calendula officinalis L.) plants at greenhouse of Shahid Bahonar University of Kerman, Iran. Results showed that application of salicylic acid and thiamine increased number of flowering stems. Stem height increased only by application of thiamine. Fresh and dry weight of the plants affected by all treatments. Foliar spray of all treatments significantly influenced chl.b and total chl contents but differences in the amount of chl.a and carotenoids content was not significant. Application of all treatments reduced stomatal length while number of stomata and electrolyte leakage reduced only by application of salicylic acid. The highest amount of reducing sugars obtained by application of ascorbic acid at 200 ppm and thiamine at 100 ppm, respectively. Application of salicylic acid and thiamine significantly increased the amount of medicinal compound hyperoside.