arbon dioxide enrichment can use for reduction of product time, increase plant growth and quality in greenhouses. To evaluate the effects of different concentrations of carbon dioxide on growth traits of two ornamental species (Ficus benjamina and Ficus elastica), a split plot experiment based on completely randomized design was conducted with three replications in the greenhouse at Ferdowsi University of Mashhad. Treatments were two species of ornamental species and three concentrations of carbon dioxide (380 controls, 700 and 1050 ppm). The results showed that with increasing carbon dioxide concentration of 380 ppm to 1050, the number of leaves and leaf area (P<0.05) and the root / shoot ratio, shoot fresh weight and plant height were significant (P<0.01). The interaction effect of species and carbon dioxide was not significant in all traits. In generally, the increase of carbon dioxide concentrations was effective on improvement of physiological and morphological traits of two ornamental species.

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