Study On The Effects Of Three Kinds Of Herbiside On The Growth And Physiological Indexes Of Walnut Seedling

This trial studied the effects of three kinds of daily weed killers of farmland, the sweet phosphine of glyphosate, clethodim, fenoxaprop-p-ethy> on the pure.growth. MDA accumulation, the relative permeability of plasma membrane and chlorophyll content respectively. It aimed to explore the physiological mechanisms of inhibiting and promoting functions of the three farmland daily herbicides and select a kind of the best one, which could kill the weeds effectively and be safe to the walnut seedling growth. The results showed as followings:Three were significant difference in the influences on the walnut seedling growth and physiological indexes of the three herbicides under daily dosage. Glyphosate brought the biggest vice-effects, clethodim took the second and fenoxaprop-p-ethyake minimum: (1)As to the pure growth, MDA accumulation, the relative permeability of plasma membrane and chlorophyll content, glyphosate had evident influences on them in the daily dosage, 1/2 and 1/4 of the daily dosage . The walnut seedling dried and died twenty days later. (2)The influences of clethodim in different concentration such as double daily dosage, daily dosage and 1/2 of daily dosage on the above four indexes demonstrated differently, the more concentration was, the more severe the influence. was. With the concentration reducing, the influence weakened gradually.(3) Double daily dosage, daily dosage and 1/2 daily dosage of fenoxaprop-p-ethy exerted a slight vice-influence to the MDA accumulation, the relative permeability of plasma membrane and chlorophyll content. (4)On the later stage of using the three medicine, their influences on the different physical indexes and the pure growth reduced gradually and disappeared completely after two months .The results of the trial concluded that when carrying on the chemical weeding in Walnut nursery or in intercropping areas between Walnut and crops, the proper protective measures must be taken not to spray Weed killer liquid on the Walnut leaves as possible if using the sweet phosphine of glyphosate. However, clethodim could be used under the concentrations of 1.25ml/kg and the safe used concentrations of fenoxaprop-p-ethy were less than 2.0ml/kg and took the same proper protective measures so as not to spray the killer liquid on the Walnut leaves.