Effects of various nitrogen sources on some morpho-physiological characteristics of rosemary (Rosmarinus officinalis L.) under in vitro conditions

To investigate the effects of different nitrogen sources including ammonium nitrate, asparagine, and glutamine in five concentrations of 0, 50, 100,150, and 200 mg l-1 on some physiological and biochemical characteristics of rosemary (Rosmarinus officinalis L.), an experiment was conducted in a completely randomized design with five repliacations. The indices including plant height, shooting rate, number of leaves, necrotic leaf size, chlorophylls a, b, and total chlorophyll content, and the content of carotenoids, phenols, and flavonoids were measured. The results showed that the nitrogen sources significantly (P≤0.01) affected the all measured indices except the necrotic leaf size. The results of means comparison showed that the highest shooting rate and number of leaves were obtained at 100 mg l-1 of glutamine and asparagine and the highest plant height was obtained at 200 mg l-1 of ammonium nitrate. Also, the highest amount of photosynthetic pigments was obtained at 50 mg l-1 of asparagine and the highest amount of phenols and flavonoids was related to 200 mg l-1 of glutamine. In general, the results showed that the various nitrogen sources studied could positively and significantly improve the morphological and physiological characteristics of rosemary under in vitro conditions.