Effects Of Acetochlor On The Growth And Physiological And Biochemical Of Corn Resistant Inbred Lines

In this study,a pair of maize inbred lines H726 and susceptible inbred lines H811,which showed resistance to acetochlor,were tested to compare the morphology and photosynthetic fluorescence of acetochlor treatment on maize inbred lines with different sensitivities.And root-tip physiological and biochemical changes,further excavating the physiological reasons for the differences in resistance of different sensitivity corns to acetochlor,clarifying the mechanism of action of acetochlor and the difference mechanism of corn's sensitivity to acetochlor.The identification and selection of herbicide maize inbred lines,germplasm creation and new breed selection provide technical support.The main findings are as follows:(1)Under acetochlor stress,the plant height and root growth of the inductive inbred line H811 were inhibited,and the leaf area and above-ground and under-ground dry and fresh weights were significantly lower than those of the control,and never recovered to the control level.In contrast,the morphological indicators of acetochlor treatment of resistant inbred line H726 had little effect.This shows that different genotypes of corn have different sensitivities to acetochlor,and the reason for the reduction in production is that acetochlor caused irreversible damage to corn at the seedling stage.(2)The apical anatomy showed that the root canopy,apical meristem,cortical parenchyma cells,and cylindrical sheath cells of the inductive inbred line H811 had significant changes.Decrease the absorption of acetochlor and reduce the harm of pesticides.This is the response mechanism of corn to acetochlor stress.The root anatomical structure of resistant inbred line H726 did not change significantly,indicating that there was a difference in resistance to acetochlor in different sensitive corn root systems.(3)The research on physiological indicators of root tip showed that the antioxidant enzyme activity and MDA content in the root tips of resistant and susceptible inbred lines were significantly higher than those in the control,but the resistant inbred line H726 had returned to the control at the 5-leaf stage.Level,and the inductive inbred line H811 did not return to the control level until the 9th leaf stage,indicating that the ability of the root tip antioxidant enzymes to regulate the activity was the main reason for the difference in resistance of maize resistant and susceptible inbred lines to acetochlor.The soluble sugar and free proline content in the root tip of the inductive inbred line H811 was significantly higher than that in the resistant inbred line H726,indicating that acetochlor has a greater effect on theroot system of the inductive inbred line H811.(4)Studies on photosynthetic indicators showed that the net photosynthetic rate(Pn)and maximum photochemical efficiency(Fv/Fm)of the inductive inbred line H811 decreased,the intercellular CO2 concentration(Ci)and non-photochemical quenching coefficient(NPQ)increased,and all photosynthetic indicators It did not return to the control level until the 11 th leaf stage,and the photosynthetic index of the resistant inbred line H726 did not change significantly compared with the control.It was shown that under acetochlor stress,stomatal factors lead to a reduction in H811 recovery capacity and a decrease in photosynthetic efficiency is the reason for the difference in resistance to acetochlor between maize inbred lines and resistant inbred lines.