Evaluation of arsenate induced physiological responses in alfalfa (Medicago sativa L.)

Arsenic (As) is a ubiquitous environmental toxic metalloid that exists in both organic and inorganic forms and it‟s concentration in the environment increases due to both industrial and agriculture activities. The excessive presence of Arsenic in the environment is a serious threat to the ecosystems and human health in many regions of the world. This metalloid has not the specific nutritional role and some studies have reported its toxic effects on plants. Arsenic entrance into crops such as alfalfa can lead to a threat to consumers of plant products including human. In order to evaluate the physiological responses of alfalfa to arsenic toxicity, in the present research, effects of different concentrations of sodium arsenate solution (0, 10, 15 and 20 ppm) on growth, photosynthetic pigments as well as soluble and insoluble sugars contents in shoots and roots of alfalfa plants was investigated in the hydroponic culture and under controlled conditions. Results indicated that all concentrations of arsenate led to a significant reduction (P≤0.05) in growth parameters, contents of photosynthetic pigments, soluble and insoluble sugars in roots and shoots compared to the control. Concerning the results, it seems that arsenate caused growth and development disruption in alfalfa via inducing phytotoxicity by interaction with physiological activities and damaging photosynthetic apparatus

کلیدواژه ها:

Arsenic ، Phytotoxicity ، Alfalfa