Effects of crop plants extracts, wheat (Triticum aestivum L.) and barely (Hordeum vulgare L.) on the growth of aquatic algae in the Northern part of Iran

In recent years, there has been an apparent increase in the occurrence of harmful algal blooms. The potential of barley (Hordeum vulgare L.) straw extract to inhibit algal growth was assessed. Algal growth in water of Anzali lagoon was inhibited by the addition of barley straw (1% volumetric), with the chlorophyll a concentration remaining below the original level (40 µg l-1) throughout the experiment. In contrast, in the presence of wheat straw, algal biomass increased, reaching a final chlorophyll a concentration of 1160 µg l-1 after 28 days. Analysis of the remaining particulate straw at the end of the experiment showed that the lignin content of barley straw had increased significantly (p<0.05). Beside, the bioassays, which were conducted to determine the efficacy of barley straw in controlling algal growth of 10 freshwater species, the results indicated that barley straw liquor inhibited the growth of three nuisance algae common in freshwater: Synura petersenii, Dinobyron sp., and Microcystis aeruginosa. However, the growth of Selenastrum capricornutum, Navicula sp., Spirogyra sp., and Oscillatoria lutea were significantly (p<0.05) increased in the presence of the straw liquor. The growth of remainder, Ulothrix fimbriata, Chlorella vulgaris, and Anabaena flos-aquae, showed no significant (p<0.05) difference from controls.