Effect of different levels of nitrogen in nutrient solution on the qualitative and quantitative traits of geranium (Pelargonium hortorum cv. Bulles eye)

To evaluate the effect of limited application of nitrogen (N) on the height control of geranium (Pelargonium hortorum) and improving its quality performance، an experiment was conducted based on a complete randomized block design with three replications in the greenhouse environment through the years 2011-2012. Geranium seedlings were cultivated in the pots filled with peat-based substrate (peat، 80 vol. percent + sandy loam field soil 20 vol. percent). For the limited application of N، four different nutrient solutions with the same macro and micro elements، except N levels of 2. 5، two، 1. 5 and one mM were applied. The rate of ammonium to nitrate nitrogen for all treatments was kept as 2 to 80 percent. The traits such as plant height، number and length of shoots، number of florescence and number of flowers in the florescence، pedicle length and leaf number، leaf area، chlorophyll، antocianins، fresh and dry weight of shoot and root were measured at the end of the experiment. Limitation of N application from 2. 5 mM to 1. 5 mM in the nutrient solution، although reduced the length of shoot، but did not affect negatively the quality of plants. Farther decreasing of N level to 1 mM، negatively influenced the all quality and quantity parameters of the plant and may not be introduced for production of geranium.