Cadmium Induced Ultrastructural Changes in Chloroplasts of Elodea nuttallii (Planch). H. St. John Leaves

The effect of cadmium (Cd) on the ultrastructure of plastid apparatus in leaves of Elodea nuttallii (Planch). H. St. John was investigated in experimental conditions using transmission electron microscopy (TEM). The experimental plants were cultivated in a green house environment after preliminary adaptation. The plants were exposed to Cd during 5 days period with concentrations 1 mg/l and 3 mg/l, consistent with previous studies. Cultivated plants under condition of the experiment without Cd were used as the controls. The results showed that at concentration 1 mg/l Cd chloroplasts have a well organized internal membrane system relative to the control, but fragmentation and weak swollen thylakoids were observed. Increasing of cadmium concentration at 3 mg/l Cd show hardly affected plastid ultrastructure, as swollen thylakoid membrane and reduction of grana stacks. The established structural changes of photosynthetic apparatus of E. nuttallii are analyzed and compared to previous researches of cadmium toxicity on E. canadensis under the same conditions.