Physiological and biochemical changes caused by 2,4-d, atrazine and metolachlor which are synthetic herbicides in corn (Zea mays L.) varieties

In this thesis work were investigated the physiological and biochemical responses depended on toxic effect caused by different concentrations of synthetic herbicides called as 2, 4-D, metolachlor and atrazine in the seedlings that belong to three corn varieties. The corn varieties are the standard seed of Zea mays L. saccharata, Zea mays L. Danona cv. and hybrid seeds of Zea mays L. Advanta 2898 cv. 15-day old seedlings for variety were divided into 4 groups consisting of the same number of seedlings and applied for four variety doses of herbicide. In these applications for seedlings was preferred hydroponic method to root. In the different treatments on seedlings were determined such growth parameters as root-shoot length growth and the amount of dry weight per fresh weight. Besides, it was also made pigment analysis in the leaves, as well as proline (PRL), malondialdehyde (MDA), the relative ratio of reduced glutathione (GSH) and oxidized glutathione (GSSG), superoxide dismutase (SOD), catalyses (CAT) analysis in the leaves (L) and the root (R). According to the results, three herbicides led to inhibitory effect on the growth parameters of seedlings but more prominent for 2,4-D. Also, all of the herbicides have increased destruction of pigment (chlorophyll (a+b), carotenoids) in L. MDA has increased in the roots of seedlings applied for 2,4-D, but it has decreased in L. The PRL and GSH/GSSG have increased in both R. and L. SOD has decreased in R, but it has increased in L. CAT has decreased in both. Secondly, in the seedlings applied for atrazine, MDA has increased in both. PRL has decreased in both for 1000 μM, but it has increased in L for 200 and 500 μM. GSH/GSSG has decreased in both. While SOD has increased in both, CAT has decreased. Finally, in the seedlings applied for metolachlor, MDA has increased in both. PRL has increased in R for 100 and 500 μM, but decrease for 1000 μM. PRL in L. has increased, but decreased in the danona and pure corn for 1000 μM. GSH/GSSG has decreased in R., but has increased in L. While SOD has decreased in both, CAT has increased. Generally, the toxic effect of 2, 4-D was found to be stronger than the others. This effect, in particular pure corn, has occurred serious damages.