Study On The Toxicity Mechanism Of Heavy Metal Manganese And Copper To

Manganese and copper are not only essential nutrition elements for plant growth and development, but also poisonous heavy metal elements.This study with different concentrations of Mn and Cu respectively to intimidate the S. polyrrhiza, which use a variety of physiological and biochemical experiment means to study the poisoning mechanism.The results are as follow:The effects of different concentration of Mn (0,0.02,0.04,0.06,0.08,0.10 mmol/L) in the Spirodela polyrrhiza was studied in this article.The oxidative damage, antioxidant system and the influence of Ca2+ -ATP enzyme activity changewas analyzed in the S. polyrrhiza. The Fourier transform infrared spectroscopy (FTIR) was used to analyze the change of its infrared spectra. The results showed that:(1) Mn stress caused obvious oxidative damage,such us the dramatical increase of the generation rate of O2-, the accumulation of H2O2 and MDA in great quantities, and the obvious decreases of the content of soluble protein and photosynthetic pigment in leaves. The content of the soluble sugar rised after the fall in short. (2) The antioxidant system has been destroyed by Mn stress. Along with the increase of concentration of Mn, the activity of catalase (CAT) and superoxide dismutase (SOD) decline after increasing. But the activity of peroxidase (POD) in leaves increases gradually, and the levels of GSH, Vc and Ve increased sharply. (3)The content of proline increased obviously. The activity of the Ca2+-ATP enzyme obviously decreased after increasing in first. (4) The infrared spectra showed that the peak increased firstly and then decreased in the place of 3396 cm-1,2920 cm-1,1062 cm-1,1658 cm-1. Which reflected the content of amino acid, sugars, proteins and carboxylic acid were obviously effected under the Mn stress. (5)The total antioxidant capacity of the S. polyrrhiza decreased. (6) Analysis of nutrient elements showed that the levels of total K、P、Mg、S、Fe fell and the level of total Ca increased initially only to decline later. Obviously, the Mn treatment caused obvious oxidative damage in S. Polyrrhiza. The balance of antioxidant system has been broken. The activity of the Ca2+-ATP enzyme changed obviously. In addition, the content of amino acids, sugars, carboxylic acid were also significantly affected.The nutrient element balance has been broken in the body of the S. polyrrhiza. In other words, the Mn stress has caused obvious damage in S. polyrrhiza.2、The effects of different concentration of Cu (0,0.05,0.10,0.15,0.20,0.25 mmol/L) in the Spirodela polyrrhiza was studiedand in this artical. And the oxidative damage, antioxidant system and its effects on the mineral elements content changes was analyzed.The results showed that:(1) Mn stress caused obvious oxidative damage,such us the dramatical increase of the generation rate of O2-, the accumulation of H2O2 and MDA in great quantities, and the obvious decreases of the content of soluble protein and photosynthetic pigment in leaves. (2) The antioxidant system has been destroyed by Mn stress. Along with the increase of concentration of Mn, the activity of catalase (CAT)andperoxidase (POD) decline after increasing. But the activity of superoxide dismutase (SOD) in leaves decreases gradually, and the levels of GSH and Ve increased sharply. (3)The total antioxidant capacity of the S. polyrrhiza decreased. (4) Analysis of nutrient elements showed that the levels of total K、P、Mg、 S、 Fe%、Ca fell. Obviously, the Cu treatment caused obvious oxidative damage in S. Polyrrhiza. The balance of antioxidant system has been broken. The total antioxidant capacity of the S. polyrrhiza decreased. The nutrient element balance has been broken in the body of the S. polyrrhiza. In other words, the Mn stress has caused obvious damage in S. polyrrhiza.