دانلود رایگان مقاله انگلیسی دخالت سه علف کش در جذب آهن در گیاهان ذرت - الزویر 2018

abstract

The use of herbicides to control weed species could lead to environmental threats due to their persistence and accumulation in the ecosystems and cultivated fields. Nonetheless, the effect of these compounds on plant mineral nutrition in crops has been barely investigated. This study aimed at ascertaining the effect of three herbicides (S-metolachlor, metribuzin and terbuthylazine) on the capacity of maize to acquire iron (Fe). Interferences on plant growth and reductions on the Fe contents were found in the plants treated. Furthermore, root cell viability and functionality losses were ascertained following the treatments, which, in turn, decreased the amount of phytosiderophores (PSs) released by the roots. An investigation carried out in greater depth on root apices of treated plants using an FE-SEM (Scanning Electron Microscope) coupled with EDX (Energy Dispersive X-ray) indicated that the reductions on Fe content started in this part of the roots. Lastly, decreases were found also in copper (Cuþ2 ), zinc (Znþ2 ) and manganese (Mnþ2 ) content in root apices.

5. Conclusions

In conclusion, our experiments showed alterations in root growth and loss of cell viability and functionality following the herbicide treatments. The release of PSs was also affected by the treatments, thus impairing the plant's capacity to assimilate Fe. A further in-depth analysis conducted on radical apices revealed that the inhibition of Fe assimilation begins here. In treated plants, root apices showed decreases in Fe content which affected the amount of the nutrient in the entire root. Regarding the other cations investigated (Cu, Zn and Mn), our experiments showed reductions in their concentrations in root apices. As with Fe, these interferences can be ascribed to a reduced absorption capacity seen in treated root apices.