قدرة نبات الشمبلان Ceratophyllum demersum L. في إزالة بعض المعادن الثقيلة وتشخيص التغايرات الوراثية المحتملـــة باستخدام بعض المؤشرات الجزيئيــة.

The ability of Ceratophyllum demersum L. in removing some heavy metals and diagnosing potential genetic variations by using some molecular markers.

This study was conducted to evaluate the efficiency of the aquatic plant Ceratophyllum demersum L. in removing three heavy metals which are (Lead, Nickel and Cadmium) when they are present in one water basin, individually and collectively, and the effect of these metals on the genetic material of the plant, different concentrations of these metals were used ( 2.5,5,7.5) mg/L and three replicates for each concentration. Water and plant samples were collected after (5, 10, 15, 20) days from the laboratory experiment basins for the purpose of measuring the concentration of the remaining metal in the water solution as well as the amount of metal accumulated in the plant. The bioconcentration factor of the plant was also calculated and the efficiency of the plant in removing The three metals as percentages of removal from water. The highest removal percentage of lead metal was (%93.91) in the experiment of mixing lead and nickel metals at a concentration of 7.5 mg/L during the treatment period (20) days, while the lowest removal percentage was (%33.97) in the experiment Three metals were mixed at a concentration of 7.5 mg/L during fifth day of treatment, while the highest percentage of removal of nickel metal was (%63.53) in the experiment of single metals at a concentration of 2.5 mg/L during the treatment period (20) days or less Removal percentage reached (%11.70) in the experiment of mixing three metals at a concentration of 7.5 mg/L during during fifth day of treatment. As for cadmium metal, it reached the highest removal percentage (%83.30) in the experiment of single metals at a concentration of 7.5 mg/L during the treatment period (20) days and the lowest removal percentage was (%33.14) in the experiment of mixing three metals at a concentration of 2.5 mg/L during during fifth day of treatment, as well as the plant samples were taken for the last period of treatment for the purpose of conducting molecular tests. The results showed that the accumulation of the three minerals in plant tissues increases with the increase in the time period of exposure to the metal, as well as the value of the bio-concentration coefficient increases with the increase in the duration of exposure. The results of the statistical analysis showed that there were significant differences at the probability level (p<0.05) between the concentrations and durations of treatment for the plant and some water concentrations.

As for the results of the molecular aspect, plant samples were taken at the end of the experiment for the purpose of conducting molecular tests. The Random Amplification Polymorphic DNARAPD technique and the Inter Simple Sequence Repeat ISSR technique were used for the purpose of detecting the genetic toxicity caused by the heavy metals lead, nickel and cadmium for twenty-two A sample that included single experiments, two-metal and three-metal interference, three primers of the RAPD index, the results showed a doubling, the total number of bundles was 288, the number of polymorphic bundles was 11, monomorphic bundles 9, and rare bundles 4, the percentage of polymorphism was 46.36%. Polymorphic 9, monomorphic 8 and rare 2 and the polymorphism percentage was 48.5%.
The dendrogram for evaluating the genetic distance resulting from treating samples with different concentrations of heavy metals through the RAPD index showed that the similarity percentage decreased to 66% in the treatment of lead and cadmium for concentrations of 5,7.5 mg/l and for interaction of metals for nickel and cadmium for concentration of 7.5 mg/l and for treatment The triple interaction of lead, nickel and cadmium to a concentration of 7.5 mg / l with the control treatment, while through the ISSR index, we note that the triple interaction coefficients for concentrations 7.5, 5, 2.5 mg / l decreased to 50,60, 66%, respectively with the control treatment, the study concluded The current study showed that Ceratophyllum demersum L. plant showed a high efficiency in removing the three heavy metals, lead, nickel, and cadmium from water. The highest removal percentage recorded by the plant was for lead, followed by cadmium, then nickel. Therefore, we recommend applying the phytoremediation technology to remove pollutants from water, as it is environmentally friendly and low in cost. Dilution of polluted water to increase the efficiency of the plant in treatment.