عنوان مقاله [English]
Introduction: Cultivation of medicinal and aromatic plants has always had a special situation in the traditional system of agriculture and these systems have played a major role in the diversification and sustainability of agricultural ecosystems. Tend to produce medicinal and aromatic plants and demand for natural products, especially in terms of ecological culture in the world is increasing. Ajowan is an annual herbaceous plant from the Apiaceae family. Biological fertilizers produced by the activity of microorganisms are associated with nitrogen fixation or availability of phosphorus and other nutrients in the soil. Enrichment means increasing the concentration of nutrients in plants especially micronutrients. Application of biological fertilizers instead of using chemicals is one of the most important nutritional strategies in sustainable management of agro ecosystems. In this regard, the effect of enrichment with bio-fertilizers and micronutrients on Ajowan (Carum copticum L.) germination characteristics was studied at Birjand Agricultural Research Laboratory.
Materials and Methods: A factorial experiment based on a CRD (completely randomized design) was conducted with three replications at Birjand Agricultural Research Laboratory during 2011. Experimental treatments consisted of bio-fertilizer application with three levels including without inoculation, and seed inoculation with Azospirillum and Azotobacter and seed enrichment with ten different treatment levels including without enrichment, and enrichment using 1, 2 and 3 mM of Fe, Zn and Mn elements. Bacteria were provided by Soil and Water Research Institute of Tehran. Initially, the seeds were disinfected through immersing them in 1% sodium hypochlorite for 3 minutes and then washing them with the tap water for 2-3 times. For the Enrichment of seeds, depending on the treatments, Petri dishes were treated with 10 ml of micronutrients solution for 24 hours. Then for bacterial inoculation depending on the type of treatments, seeds were soaked in 7 ml of inoculums containing 108 alive and active bacteria per ml for 5 hours. In each treatment, 15 seeds were placed in Petri dishes sealed with parafilm and placed in a germinator set at 70% RH and 25/15 °C. The traits studied were: germination percentage, germination rate, root and shoot length, as well as root and shoot fresh and dry weight. Before analyzing the data, normality test was performed and analysis of variance was performed using Genstat and graphs were drawn using Excel software.
Results and Discussion: The Analysis of variances results showed that seed inoculation with biological fertilizers and micronutrients significantly increased germination rate, root and shoot length, root fresh weight and dry weight of root and shoot of Ajowan compared with the control. Results showed that there were not significant differences between treatments in terms of germination percentage. Using micronutrients for seed enrichment caused increased germination rate. The maximum germination rate value was obtained from the Mn 1mM treatment (2.164 seeds per day), and. its minimum value was obtained from Zn1 (1.55 seeds per day). The maximum and minimum values of root length were obtained from the combined treatments of azotobacter + Fe2 and Azospirillum + Zn3, respectively. The maximum and minimum values of shoot length were obtained from the combined treatments of azotobacter + Mn2 and Azospirillum + Zn3, respectively. The highest and lowest values of shoot dry weight were obtained from azotobacter + Fe3 and azotobacter, respectively. The highest and lowest values of root dry weight were obtained from Zn1 (2.35 mg) and Mn2 (0.4 mg), respectively. The highest and lowest values of root fresh weight were obtained from Azospriliium+ Mn3 and Azospriliium+ Zn2, respectively. The highest and lowest values of shoot fresh weight were obtained from Azotobacter+Mn2 and Mn3, respectively.
Conclusion: During the evaluation of the measured traits regarding to bio fertilizers application on ajowan, it was observed that all biological treatments were superior to the control (non-biological fertilizer) and Azotobacter was the most effective amongst them. Bio fertilizers applications used in this study showed significant effects on root and shoot length, as well as fresh weight of root and shoot. The use of micro-nutrients on ajowan, showed that the application of 1 and 2 mM of Mn and all three concentrations enhanced the examined characteristics, while the application of 1 mM of Zn was just effective on root and shoot dry weight. Overall,application of these micronutrients had significant effects on germination rate and root length and fresh weight of root and shoot as well as dry weight of shoot and root.