Evaluation of Different Levels of Nitrogen and Phosphorus Fertilizers on Shoot and Root Characteristics of Echinacea purpurea

Abstract

Introduction: Purple coneflower with scientific name Echinacea purpurea (L.) is an herbaceous perennial plant native to North America and is the one of the most important medicinal plants in the world. Root of Echinacea purpurea is commonly used around the world for stimulation of immune system. It is used as herbal medicine in respiratory infections, against malignant tumors and several inflammatory conditions However, nitrogen and phosphorus are the main elements that make up the proteins in plants and herbs for natural growth, especially is necessary in their productive organs. The results showed that nitrogen and phosphorus are important in continuation of flowering, the flowers fresh and dry weight and in essential oil. Fertilization of E. purpurea plants indicated that in absence or at low levels of nitrogen fertilization (0 and 100 kg acre-1), the addition of 50 and 100 kg acre-1 of potassium increased aerial parts, flower heads and root yield. Another report indicated that highest aerial biomass and root yield in E. purpurea was obtained with 100 kg ha-1 of nitrogen at constant rates of phosphorus and potassium. Polyphenol content was not influenced by nitrogen fertilization and values fluctuated between 2.4 and 5.4 % in the aerial part at flowering and between 1.6 and 3.5 % in the roots. Fertilization with nitrogen caused a decrease in the concentrations of echinoside. Echinoside content was 1.16 % without nitrogen fertilization, and 0.94 % with nitrogen fertilization. Materials and Methods: To evaluate the effect of different levels of nitrogen and phosphorus on growth and yield of coneflower, a factorial experiment in a completely randomized design with three replications was conducted in Ferdowsi University of Mashhad. Treatments were included three levels of nitrogen (0, 1 and 2 gr urea per kilogram of soil) and three levels of phosphate fertilizer (0, 0.75 and 1.5 gr of phosphate (P2O5) per kg of soil). Nitrogen fertilizer was applied to the soil before planting and one month after transplanting seedlings and phosphorus fertilizer was added to the soil after transplanting. Results and Discussion: A difference in plant height at different levels of nitrogen was significant. By increasing the amount of nitrogen to 1 gr, plant height from 69.44 increased to 81.11 cm. Number of lateral shoots wasn’t significant in any levels of nitrogen and phosphorus. Increasing of nitrogen from 0 to 2 grams per kg of soil increased leaf weight from 2.4 to 7.5 g. However, with increasing levels of phosphorus, weight and leaf area increased. So that the treatment without phosphorus, dry weight was 4.37 grams and in 1.5 grams of phosphorus was the highest leaf dry weight with 5.77 gr. With increasing levels of nitrogen from 0 to 1 gram, shoot dry weight increased and with increasing nitrogen from 1 to 2 grams of weight shoot dry weight was low. Treatment with 1 gr of nitrogen per kilogram of soil had the highest stem dry weight per plant with 8.7 grams and showed significant differences with other treatment. Based on the results, the effect of nitrogen fertilizer treatments in the number of flowers and flower dry weight was significant at 1%, the effect of phosphorus on flower dry weight was significant. But the interaction of nitrogen and phosphorus fertilizer treatments in any levels was not significant. The highest SPAD index in1.5 gr of phosphorus and lowest (53.74) in the treatment without phosphorus was observed. Different levels of nitrogen fertilizer had not significant effect on the length and diameter of the root but a significant effect of phosphorus on root length was showed. It seems nitrogen in 1 gr per kg is related to increase photosynthesis and the growth of organs. Nitrogen with increasing in meristem cell division can increase vegetative growth and plant size. Zeinali et al (1387) reported that phosphorus can increase carbohydrates and mineral combinations in the shoots, flowers and roots. As a result increase in shoots, roots and flowers dry weight is related to nitrogen and phosphorus. Conclusion: In general the results showed that with increasing nitrogen fertilizer height, flower number and shoot dry weight was significantly increased. Also, increasing the amount of phosphorus up to 1.5 gr per kilogram leads to an increase in plant roots. Due to the interactions of nitrogen and phosphorus in leaf dry weight and root dry weight, nitrogen and phosphorus in 2 and 5.1 gr per kg of soil had the best results.

Keywords

• Chlorophyll index
• Dry weight
• Fertilizer