Abstract The study investigated the saline-alkaline tolerant ability of Iris pseudoacorus seedlings in coastal regions as well as the nitrogen and phosphorus removal capability under hydroponic culture. The growth characteristics, physiological response of I. pseudoacorus and the removal efficiency for nitrogen and phosphorus by I. pseudoacorus were analyzed in saline-alkaline water. The results showed the limits of salinities that I. pseudoacorus could tolerate were less than 9‰, 6‰ and 3‰, corresponding the pH values of the water were 7, 8, 9, respectively. Within the limits, the differences of water content and leaf chlorophyll content between the plants in salt-alkali treated groups and those in control group (without salt or pH stress) were less than 5.0%. The concentrations of Na+, Cl-, betaine and soluble carbohydrates increased by 130% at most within the limits. At low salinities and low alkalinities (salinities were 3‰ and 6‰ while the pH was 7and salinity was 3‰ while the pH was 8), the relative growth rate of the plants in treated groups was 0.6~6.1% higher than those in control group, and I. pseudoacorus removed 0.046mg/(g·d) and 0.020mg/(g·d) of total nitrogen and total phosphorus, respectively. Beyond the limits, however, the concentrations of Na+ and proline of I. pseudoacorus were 14.0 and 91.4 times higher than those in control group in response to salt-alkali stresses. In addition, the growth of I. pseudoacorus were inhibited and the removal efficiency for nitrogen and phosphorus reduced significantly. In summary, I. pseudoacorus could be chosen to purify the coastal water with low salinity and low alkalinity.
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Received: 01 April 2015
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