Piriformis Indica Alleviates Phytotoxicity Of Acetochlor To Rape And Its Mechanism

In order to find a solution to alleviate the phytotoxicity of acetochlor to crops,this study used rapeseed as the test crop,P.indica as the test strain,and acetochlor as the test agent.Under potting conditions,we used different concentrations of P.indica to seed rape and measured the influence of acetochlor to rape.The results showed that when potted with 1 g of P.indica dressing with 10 g of rapeseed,P.indica had certain inhibitory effects on the plant height,root length,and fresh weight of individual plants.When 100 g of rapeseed was seeded with 1 g of P.indica,it had significant growth promotion effects on rapeseed,and the growth rates on plant height,root length,and fresh weight per plant were 16.62%,29.85%,20.66%;under potting conditions,the application of acetochlor has a certain adverse effect on the growth of rape seedlings.Among them,as the concentration increased,the effect of acetochlor on rape seedlings became more and more obvious.When the concentration of acetochlor exceeded 1 200 g/hm~2,the inhibition rate of acetochlor on the plant height of rapeseed was about 60%;the inhibition rate on fresh weight of rapeseed seedlings is about 58%;the inhibition rate on root length of rapeseed seedlings is between12.78%-26.99%.However,rape seed dressing with P.indica was relatively mild.When 1 g of rapeseed was added with 10 g of P.indica,using different effective ingredients(400,800,1200,2400 g/hm~2)of acetochlor,the overall mitigation effect was the best.Among them,the recovery rate of rape plant height was 30.79%,60.99%,26.99%,26.49%;the recovery rate of rape root length was 33.69%,21.51%,58.75%,31.67%;the recovery rate of fresh weight of rapeseed was 75.92%,45.50%,7.25%,33.33%.Under field conditions,P.indica significantly promoted the growth of rapeseed plant height and fresh weight per plant;the test results were basically consistent with those of potted plants;meanwhile,acetochlor had good control effects on main weeds in rapeseed,such as Alopecurus aequalis Sobol,Malachium aquaticum(L.)Fries(Stellaria aquatica(L.)Scop.),Veronica didyma Tenore.We measured the effect of acetochlor on the growth rate of P.indica by the method of mycelial growth rate.The results showed that the effect of acetochlor on the growth rate of P.indica was significant.As the concentration increased,the effect on the growth of mycelium also increased.The effect of acetochlor on the dry and fresh quality of P.indica was measured by the mycelium suspension culture method,and the results showed that the effect of acetochlor on the dry and fresh quality of P.indica was significant,and with the concentration of the increase has a greater impact on dry and fresh quality;When the concentration of acetochlor exceeds 200 mg/L,the growth of P.indica basically stops;through microscopic observation,when the concentration of acetochlor is high,the P.indica mycelium is caused by the toxicity of acetochlor Insufficient stretch,dense growth and shrinking state;and with the increase of acetochlor concentration,the germination of P.indica spores was also less than that under normal conditions.We used GS-MS gas chromatography mass spectrometry to determine the degradation dynamics of acetochlor in P.indica liquid.The results showed that the half-life of acetochlor in P.indica was significantly shortened,all of which were below 10 d;and the half-life of acetochlor was relatively extended with the increase of acetochlor concentration;residual determination results in the residue were analyzed by regression analysis.We concluded that acetochlor degraded faster in the soil in the early stage,and degraded slowly in the later stage,in accordance with the later period.Generally,the half-life of acetochlor is lower when the mycelium is added to the rapeseed seedlings than when the mycelium is not added.It indicated that P.indica could accelerate the metabolism of acetochlor in rapeseed to a certain extent,and accelerate its degradation rate.We measured the mass concentration of GSH and the activities of GST and SOD in rape after seed dressing with P.indica under potting conditions.The results show that acetochlor can stimulate the GSH mass concentration,GST and SOD activity of rapeseed.A suitable amount of seed dressing P.indica can enhance the activity and mass concentration of rapeseed-related detoxifying enzymes,and strengthen the rapeseed and soil metabolic ability,alleviate the effects of acetochlor damage on rape.