Effect of arsenic treatments on physiological parameters of sunflower and maize plants81-84Views:152
The environment is contaminated with heavy metals and other toxic compounds. One of the most important toxic element is the arsenic (As).
The objective of our study was to investigate the effect of As on fresh and dry weight of sunflower and maize in the early growth phases.
Seedlings were grown in climate room on nutrient solution which were treated with 3, 10 and 30 mg kg-1 arsenic. The plants were treated separately with As(III) and As(V). After 14 day, changes in fresh and dry weight of maize shoots and roots were recorded. In the case of sunflower these parameters were measured after 21 day.
The applied As(III) and As(V) decreased the fresh and dry mass of the shoots and roots of seedlings, especially at concentration 30 mg kg-1. We can draw the conclusion that the treatments of the maize and sunflower roots with arsenic had negative effects on the biomass accumulation. We found that the sunflower plants are more sensitive to arsenic toxicity than maize plants, and all data demonstrate that the As(III) is more toxic to these plants than the As(V).
Assessment and comparison of selenium-enriched maize with sodium selenite and sodium selenate11-15Views:152
Selenium is an element of environmental interest owing to the narrow range between its nutritionally required and toxic concentrations in many organisms. Its mobility and bioavailability differ greatly depending on individual Se species. In this regard, in present study, the uptake and distribution of Se, the changes in Se content, and the effects of different concentration of Se in two forms of sodium selenite and sodium selenate on maize plants were measured in nutrient solution experiments to clarify their response to the two forms of Se. The results revealed that the Se content in shoots and roots of maize plants significantly increased as the Se level increased. Two Se forms behaved differently and the effects of toxic damage in samples which had been treated with selenite were much more than in the selenate treatments.
Analysis of maize and sunflower plants treated by molybdenum in rhizobox experiment11-14Views:180
In this study, maize (Zea mays L. cv. Norma SC) and sunflower (Helianthus annuus L. cv Arena PR) seedlings treated by molybdenum (Mo) that were cultivated in special plant growth boxes, known as rhizoboxes. During our research we tried to examine whether increasing molybdenum (Mo) concentration effects on the dry mass and absorption of some elements (molybdenum, iron, sulphur) of shoots and roots of experimental plants.
In this experiment calcareous chernozem soil was used and Mo was supplemented into the soil as ammonium molybdate [(NH4)6Mo7O24.4H2O] in four different concentrations as follow: 0 (control), 30, 90 and 270 mg kg-1.
In this study we found that molybdenum in small amount (30 mg kg-1) affected positively on growth of maize and sunflower seedlings, however, further increase of Mo content reduced the dry weights of shoots and roots. In case of maize the highest Mo treatment (270 mg kg-1) and in case of sunflower 90 mg kg-1 treatment caused a significant reduction in plant growth.
In addition, we observed that molybdenum levels in seedling were significantly elevated with increasing the concentration of molybdenum treatment in comparison with control but the applied molybdenum treatments did not affect iron and sulphur concentration in all cases significantly.
The toxicity of different selenium forms and compounds – Review33-38Views:653
Selenium (Se) is an unusual metalloid of considerable interest from both a toxicological and a nutritional perspective, with a very narrow safe range of intake. Although there are many reports about its detoxification properties, toxicity aspects of it have also been tracked for several decades. Lots of studies demonstrated that low Se is an efficacious avail whereas high Se can induce toxicity and the significant toxicity of selenium emphasizes the need to assess the health risk of various selenocompounds as nutritional supplements. The toxicity of different forms and compounds of selenium is also summarized in this review.