Effects of Nitrogen on Growth and Some Morphological Traits of Inoculated Savory Plant (Satureja hortensis L.) with Azospirillum irakense and Pseudomonas putida

Savory (Satureja hortensis L.) is one of the medicinal plants, which is used in medical and food industries. In order to investigate the effect of plant growth promoting microorganisms and different levels of nitrogen fertilizer on growth and morphological parameters of savory, an experiment was conducted as factorial randomized complete block design with four replications. The first and second factors were Azospirillum irakense (A) and Pseudomonas putida (P), respectively and the third factor was nitrogen fertilizer as urea with three levels of no nitrogen (N0), half rate (N1: 80 mg kg -1 Soil) and complete rate (N2: 160 mg kg -1 Soil). The results showed that the number of branches, root and shoot dry weights were significantly increased using each bacterium in comparison with control (no inoculation). In Azospirillum (A) and Pseudomonas (P) treatments, shoot dry weight was increased by 11 and 8 percent respectively. Also A. irakense caused a significant increase in plant height. The highest root dry weight and plant height were achieved in A treatment and the increments were 22 and 44 percentage compared to the control (no inoculation), respectively. Furthermore, A treatment increased the plant height, number of branches and shoot dry weight, and P treatment enhanced the number of branches and shoot dry weight but these treatments didn’t show significant difference with A and P, accordingly. By increasing the amount of nitrogen fertilizer, all morphological traits were significantly increased. However, between the second and third levels of nitrogen intake (N2 and N1) no significant differences were observed. Therefore, co-inoculation of this plant with A. irakense and P. putida and application of N1 level of nitrogen could be efficient in decreasing nitrogenous fertilizer demand.