Diagnosis Of Herbicide Phytotoxicity And Boron Toxicity On Tobacco And Herbicide Residue Detection

It was researched in2009that tobacco harm was caused by residue of threeherbicides and effect of boron amount on tobacco damage and tobacco growth. Theresults were as follow:1. Influence of three herbicide residue in soil on tobacco growthWhen Glyphosate Isopropylamine was higer than5.47×10^-4mg·kg^-1, obviousphytotoxicity appeared in tobacco; When concentration was above1.64×10^-3mg·kg^-1,symptom of tobacco phytotoxicity could not be recovered and tobacco yield and qualitywere severely affected; Germination energy and rate of emergence was suffered whilegermination was in normal.When mixture of bensulfuron-methyl and acetochlor was higer than1.2×10^-4mg·kg^-1, obvious phytotoxicity appeared in tobacco and tobacco yield and quality wereseverely affected; Under certain temperature, phytotoxicity index was a rising tendencyand significant phytotoxicity was not showed on tobacco by precipitation; When theconcentration was above5.0×10-5mg·kg^-1,significant effects of pesticide ongermination energy and rate of emergence in tobacco seeds were discovered.When mixture of bensulfuron-methyl and quinclorac was above1.2×10^-4mg·kg^-1, obvious phytotoxicity was formed in tobacco and tobacco yield and qualitywere severely affected; Under the condition of21.6～28.8℃, there was a positivecorrelation between temperature and tobacco phytotoxicity while precipitation was notobvious correlation with tobacco phytotoxicity. No effect of pesticide on rate ofgermination was studied; However, rate of emergence was different in different degree.2. The residue of two herbicide in soil and tobaccoThe residue of20%bensulfuron-methyl and acetochlor in soil and tobacco: In theconcentration of500X and1000X, the residue of bensulfuron-methyl in soil was0.009mg·kg^-1and0.004mg·kg^-1and the residue of acetochlor in soil was0.27mg·kg^-1and0.15mg·kg^-1after15days,respectively; bensulfuron-methyl and acetochlor in soilwere not detected after30days. In the concentration of500X and1000X, bensulfuron-methyl in tobacco was not detected and the residue of acetochlor was0.1430mg·kg^-1and0.0821mg·kg^-1after15d, separately; bensulfuron-methyl andacetochlor in tobacco were not detected.The residue of30%bensulfuron-methyl and quinclorac in soil and tobacco: In theconcentration of500X and1000X, the residue of bensulfuron-methyl in soil was0.0934mg·kg^-1and0.0445mg·kg^-1and the residue of quinclorac was1.3667mg·kg^-1and0.8146mg·kg^-1after15days; bensulfuron-methyl in soil was not detected and theresidue of quinclorac was0.5564mg·kg^-1and0.2235mg·kg^-1after30d. the residue ofbensulfuron-methyl in tobacco was0.0165mg·kg^-1and0.00943mg·kg^-1and the residueof quinclorac in tobacco was0.5836mg·kg^-1and0.3485mg·kg^-1after15days;bensulfuron-methyl in soil was not detected and the residue of quinclorac in tobaccowas0.1814mg·kg^-1and0.1023mg·kg^-1after30days.3.Effect of boron on tobacco growthEffect of boron in different treatments on the growth of tobacco was describedwith water culture and foliage spray.In the concentration of200mg·L^-1,tobacco was ledto symptom of toxicity with yellow and fading leaves,decreasing the yield oftobacco.No significant symptom was shown on tobacco in the water of borondeficiency.However,surface quality was not as good as the control;In the concentrationof0.5mg·L^-1, symptom of severe toxicity was formed,restraining the growth of tobaccoleaves.Rate and index of fertilizer injure was50%～100%and30～70, respectively;Butnew leaves grew out in normal.In the concentration of0.05～0.10mg·L^-1, tobaccogrowth was not affected by boron.