effect of elevated co2 in different fertilizer conditions on physiological traits in lemon balm (melissa officinalis) at greenhouse

increasing atmospheric co2 concentrations and nutrients supply are generally expected to enhance photosynthesis and growth of crops as a result considerably increase yields. the present study aims to investigate effects of elevated co2 and different fertilizer conditions on physiological traits in lemon balm. a factorial experiment was conducted based on completely randomized design with three replications and nine treatments at the greenhouse in 2010. the experiment factors were included three co2 concentrations (380, 700 and 1050 ppm) and three kinds of conditions fertilizer (no fertilizer, manure fertilizer and nitrogen fertilizer). the results indicated that increasing of co2 from 380 to 1050 ppm led to improve in leaf area, plant height, relative growth ratio, total dry matter and final yield of individual plant. the highest and the lowest amount of measured traits related to with and without nitrogen fertilizer, respectively. impact of elevated co2 in conjunction with nitrogen and manure fertilizers increased. these effects were more on total dry matter and final yield than other growth indices. therefore, it can be concluded that, whereas increase of temperature caused by rising co2 is not considered or there is not any limitation for resources, co2 enrichment will be improved lemon balm production.