Study of some morphological and physiological characteristics of German chamomile (Matricaria chamomilla L.) under the influence of salicylic and humic acids foliar spray

Foliar spray of chemical and organic compounds can affect the quantitative and qualitative yield of important medicinal plants such as German chamomile (Matricaria chamomilla L.). In order to investigate the effect of salicylic (control, 200, 400 and 600 μM) and humic (control, 200, 400 and 600 mg l-1) acids foliar spray on some quantitative and qualitative characteristics of German chamomile, a factorial experiment was conducted in a randomized complete block design with three replications in the research farm of Khuzestan Agricultural Sciences and Natural Resources University in 2015. The results showed that the highest number of flowers per plant was observed in 600 μM salicylic (91) and 600 mg l-1 humic (96) acids treatments. The highest fresh flower yield (1014 g m-2) was obtained from salicylic acid (400 μM) × humic acid (600 mg l-1), which was 115% higher than that of the control treatment. The use of salicylic and humic acids had a great influence on the total antioxidant capacity and the content of flavonoids, anthocyanins, and carotenoids. The highest percentage of chamazulene (6.1%) was obtained from salicylic acid (400 μM) × humic acid (600 mg l-1) treatment, and the lowest one (4.1%) from the control treatment. In total, the best results were obtained from simultaneous application of salicylic (400 μM) and humic (600 mg l-1) acids.