Isolate and Cultivate Three Species of Blue-Green Algae from Soil Southern of Iraq and Study the Effect of Purified Microcystins from Alga Oscillatoria Pseudogeminata on Seed Germination of Tomato Plant Lycopersicon Esculentum

Abstract

The present study included the diagnosis, isolation, purification and cultivation of three blue-green algal species belong to three genus represented by Aphanothece clathrata, Microcystis flos-aque and Oscillatoria pseudogeminata from the moist soil in the Al-Dafas orchards area, which is adjacent to the Tigris River in the district of Amara / Maysan province and Basra southern Iraq. The algae were cultivated in the BG-11 medium .The growth constant (k) and generation time (G) was measured for 60 days. Microcystins were purified from algae and detected qualitatively and quantitatively by using ELISA teqnique reach to 0.34 and 0.734 µg/L/50 mg of dry weight for the first and second algae respectively, While the alga O. pseudogeminata demonstrated its ability to produce microcystins at high concentration of 1.47 μg / L / 50 mg of dry weight of alga. The seeds of tomato plant Lycopersicon esculentum were treated with purified microcystins (MCs) from alga  O. pseudogeminata for 7 days with three concentrations of 0.5, 3 and 6 μg / L, in addition to the control group which was treated with distilled water. The results showed a significant decrease P≤0.05 in the germination percentage in the first and second day of the experiment under concentrations 3 and 6 μg / L reached to  0% in both compared with control group and concentration of 0.5 μg / L which their reach 26.6%. On the third to seven days of exposure, the germination percentage was range between 3.3- 86.6% when exposed to 6 µg/L compared with control group (100%). Also results showed a significant decrease p≤0.05 in the rate of germination speed, mean length of the radicale and plumule, fresh and dry weight with increasing of period exposure and purified microcystins concentration exactly at high concentration 6 μg / L.

Keywords: Purified microcystins, A. clathrata, M. flos-aque O.pseudogeminata, Seed germination, L. esculentum