efficacy of spraying a mixture of amino acids on the physiological and morphological characteristics of tuberose (polianthes tuberosa l.)

tuberose (polianthes tuberosa l.) is one of the most important cut flowers in iran. this research was conducted to investigate the effects of spraying a mixture of amino acids on the physiological and morphological characteristics of tuberose. the experiment was carried out in two successive years (2009 and 2010) using two tuberose cultivars ‘dezfuli’ and ‘mahallati’. the experiment was arranged as a factorial on a completely randomized design with 4 replications. treatments were 0, 0.25, 0.5, and 0.75 mg l-1 of amino acids. the results showed that applying amino acids improved all growth and flowering characteristics of tuberose cultivars. concentration of 0.75 mg l-1 amino acids enhanced the floral stem, inflorescence, and stem diameters. the fresh weight of floral stem increased about 22% as a result of spraying with 0.25 mg l-1 amino acid mixture. total protein and nitrogen contents of the ‘dezfuli’ cultivar showed about 60% enhancement when using a 0.5 mg l-1 mixture of amino acid. in general, the effects of amino acids on ‘dezfuli’ were greater than the ‘mahallati’ cultivar.