Effects of Bio-fertilizers on Physiological Traits and Absorption of Some Nutrients of Chicory (Cichoriumintybus L.) in Response to Drought Stress

Introduction The chicory is an economically important member of the Asteraceae family. Chicory has also been used for medicinal applications, useful to liver and gallbladder, which some of its health benefits is scientifically proved. In recent years, drought has been a serious problem in Iran. Several scientists have shown that a plant under stress will produce secondary metabolites that may influence its medicinal properties. This study aimed to investigate the effects of drought stress and bio-fertilizer application on physiological characteristics and absorption of some nutrients by chicory. Water is one of the most important environmental factors that has a significant influence on the growth and active ingredients of medicinal plants. Water shortage causes serious damage to plant growth and development. In the time of drought and salinity due to the high concentration of salts in the root zone and increase in the osmotic potential of the soil, nutrients absorption will decrease. Therefore, the decrease in soil moisture changes the rate and amount of nutrient absorption by the plant. Organic fertilizers under drought stress by increasing the proline, soluble sugars and absorption of potassium and phosphorus can mitigate drought stress impacts and increase the crop yield. The sharp decline in root growth under the drought stress condition is the main factor reducing the elements absorption capability of the plants. The combined application of Effective Microorganism (EM) and organic fertilizers is a suitable method to supply and release essential nutrients. Results of a study showed that EM inoculation with soil has not only improved the quality and quantity of crop but also enhanced the quality of soil. Application of Nano fertilizers as an alternative to conventional fertilizers resulted in slow and controlled release of nutrient in the soil. In addition, nano fertilizers increase the nutrients uptake efficiency and minimize the negative impacts of consuming too much fertilizer and reduce the frequency of fertilizer application. Drought stress decreases the potassium level in soil and consequently in the plant. The aim of this study was to examine the impacts of Bio and nano fertilizers application on physiological traits and absorption of some nutrients in chicory plant under limited irrigation. Materials and Methods To study the effects of Bio-fertilizers on physiological traits and absorption of some nutrient of Chicory (Cichorium intybus L.) in response to drought stress, this experiment was conducted in 2014-2015 growing season in a split-plot design with three replications at the Agricultural Research Institute (Chah-Nimeh), University of Zabol, Iran. The main plots were drought stresses regulated with irrigation after 90 (control), 70 and 50 percent of field capacity. Sub plots were different levels of Bio-fertilizer application inclusive of a sub-plot without fertilizer (control), inoculation of nitroxin (1 lit ha-1), effective EM (10 lit ha-1), and foliar application of Nano potassium chelate fertilizer (27%) (10 kg ha-1). The traits such as relative water content, protein percentage, chlorophyll a, chlorophyll b, total chlorophyll, flower yield, proline, flavonoid, carbohydrate, carotenoid, phosphor and potassium were evaluated. Results and Discussion Results showed that the interaction of Bio-fertilizer application and drought stress had a significant impact on all the traits except for the chlorophyll b. Increasing the stress rate, decreased the relative water content, photosynthetic pigments, carotenoid, protein percent, flower yield and phosphorus and potassium uptake. However, increase in the stress rate, increased the proline content, carbohydrate, and flavonoid increased. Bio-fertilizers application improved all the traits. The maximum relative water content, photosynthetic pigments, and flower yield were obtained from the treatment irrigated after 90 percent field capacity (FC) with EM application. The highest level of protein was obtained from the treatment irrigated after 90 percent of FC depletion and nitroxin fertilizer application. Maximum protein and carotenoid level were observed in irrigation treatment regulated with 50 percent FC and Nano potassium chelate fertilizer application. Maximum phosphorus and potassium uptake achieved from the treatment irrigated after 90 percent FC and Nano potassium chelate application. It is concluded that the increase in drought stress significantly decreases the photosynthetic pigments and absorption of nutrients. Conclusions According to the results, the use of Nano potassium chelate fertilizer, microorganism bio-fertilizer (EM) and nitroxin had a positive impact on efficiency of chicory production.