几种玉米大田除草剂对AM真菌侵染及其酶活性的影响

在接种G intraradices和G etunicatum的玉米植株盆栽钵中 ,按大田常规用量 ,施用乙草胺、丁草胺、灵达、骠马、百草敌和使它隆 6种除草剂 ,对玉米植株的生物量、AM真菌菌丝根段侵染率、菌丝碱性磷酸酶 (ALP)和琥珀酸脱氢酶 (SDH)活性及土壤中AM真菌菌丝的总量均有显著影响。第 1 0周取样 ,对玉米植株生物量影响较大的除草剂为骠马 (植株生物量为 2 1 1～ 31 3g) ,影响较小的为灵达 (植株生物量为 5 9 7～ 6 5 5g) ,而对照的生物量为 84 4～ 95 7g ;对AM真菌侵染率影响较大的为丁草胺 (AM真菌侵染率为 1 3 7%～1 8 1 %) ,影响较少的为使它隆 (AM真菌侵染率为 30 4 %～ 36 6 %) ,而对照侵染率为 6 3 0 %～ 88 2 %;对AM真菌菌丝ALP和SDH酶活性影响较大的为丁草胺 (ALP为 8 1 %～ 1 0 4 %,SDH为 1 0 6 %～ 1 4 6 %) ,影响较小的为使它隆 (ALP为 1 7 0 %～ 2 0 6 %,SDH为 2 3 1 %～ 2 8 2 %) ,而对照的ALP为 38 0 %～ 5 0 3%,SDH为4 9 7%～ 72 4 %;此外 ,除草剂对土壤中AM真菌菌丝的总量也有显著影响。

IMPACT OF HERBICIDES ON INFECTION AND HYPHAL ENZYME ACTIVITY OF AM FUNGUS

In a pot experiment,pots of maize inoculated with G.intraradices Schenck & Smith and G.etunicatum Becker & Gerdemann were treated with herbicides.The dosages of herbicides applied in the pots were the same as in the fields.The results showed that the herbicides (acetochlor,butachlor,glyphosate-isopropylammonium,aventis,dicamba,and fluroxypyr) had significant impacts on biomass of the maize,infection rate of AM mycorrhiza fungus,and hyphal enzyme activity of alkaline phosphatase (ALP) and succinate dehydrogenase (SDH),and amount of AM mycorrhiza fungal hypha in the soil.Samples collected at the 10th week showed that aventis had greatest impact on biomass of the maize (21.1~31.3 g),and glyphosate isopropylammoniun had the least (59.7~65.5g),while the biomass in the control was 85.4~95.7 g.In terms of impact on infection rate,Butachlor ranks first among the six,resulting in an infection rate of 13.7%~18.1% and Fluroxypyr the last (30.4%~36.6%),while the infection rates in the control were 63.0%~88.2%.Butachlor remained to be the first in terms of impact on ALP and SDH activities of AM mycorrhiza fungal hypha (ALP 8.1%~10.4% and SDH 10.6%~14.6%),and Fluroxypyr the last (ALP 17.0%~20.6% and SDH 23.1%~28.2%),whereas the control showed 38.0%~50.3% and 49.7%~72.4%,respectively;Besides,herbicides also affected significantly total amount of the hyphae of AM mycorrhiza fungus in the soil.