Effects of Nitrogen, Phosphorus and Potassium Fertilizers on Growth Characteristics of Two Species of Bellflower ( Platycodon grandiflorum )

Fertilization plays a vital role to enhance productivity in several medicinal plants, including Bellflower. A pot experiment was conducted in 2018 to study the effects of nitrogen, phosphorus and potassium fertilizer (NPK) on the growth of two species of Bellflower ( Platycodon grandiflorum ) in the greenhouse of Chungbuk National University. After 120 days after sowing, the plants were subjected to four different levels of treatments as T0 (no fertilizer), T1 (P+K), T2 (N+K), T3 (N+P), T4 (N+P+K) in a randomized complete block design. Comparing with the untreated plants, application of typical compound fertilizer (NPK) increased the plant height, leaf morphology, number of nodes and number of branches in the two species of Bellflower. But interestingly, the stem diameter and leaf color decreased with the application of NPK. However, the absence of potassium fertilizer (N+P) provided a negative effect on the growth characteristics compared to other treatments in Bellflower. In the case of P. grandiflorum with green petals, the highest leaf morphology values (plant height-65.2 cm, 5.1-leaf width, 7.1-leaf length, 7.7-number of branches, and 13.8-number of nodes per plant) were obtained from the T4 treatment groups. Whereas, the root characteristics showed similar results as leaf characteristics, but no significant differences were observed among the treatment groups. Taken together, the results obtained from the present study suggest that it may assist to identify the optimal N, P and K availability in the soil, enabling maximal growth and production of P. grandiflorum for. duplex and P. grandiflorum with green petals.