特丁噻草隆高效液相色谱分析方法研究

本文采用高效液相色谱法,以甲醇＋水为流动相,使用Agilent ZORBAX Extend-C18不锈钢柱和二极管阵列检测器,在检测波长256nm的条件下检测特丁噻草隆含量。结果表明该检测分析方法线性相关系数为0.999 0,平均回收率为98.74%,标准偏差为0.47,变异系数为0.50%,简便易行、快速准确。     

A psbA mutation in Kochia scoparia (L) Schrad from railroad rights-of-way with resistance to diuron, tebuthiuron and metribuzin

Kochia [Kochia scoparia (L) Schrad] has become resistant to many herbicides used in cropland and railroad rights-of-way in North Dakota and Minnesota. Kochia scoparia plants that had survived annual treatments with diuron and tebuthiuron were sampled along railroad rights-of-way in North Dakota and Minnesota. The samples were screened in the greenhouse for resistance to diuron, tebuthiuron, metribuzin and bromoxynil from 0.5x to 32x the recommended use rates. A resistant K scoparia accession (MN-3R) was confirmed with resistance up to 16-fold higher than recommended use rates for tebuthiuron and diuron and up to 4-fold higher for metribuzin. However, the resistant K scoparia accession was susceptible to bromoxynil even at 50% of the recommended use rate. The herbicide binding region of the psbA gene fragment of eight resistant (R) and seven susceptible (S) K scoparia accessions was PCR-amplified and sequenced for detection of mutations. The psbA gene of four R K scoparia accessions was mutated at residue 219 with substitution of isoleucine for valine (GenBank accession number AY251265). The seven S K scoparia accession sequences were wild-type at this residue (GenBank accession number AY251266). The other four R accessions sequences showed a previously known triazine R mutation with substitution of glycine for serine at residue 264. All 15 K scoparia accessions were wild-type at all other psbA residues within the region analyzed. Resistance to diuron, tebuthiuron and metribuzin among the railroad rights-of-way K scoparia is probably due to the mutation at residue 219 of the psbA gene in some plants, but due to the previously reported Ser(264)Gly substitution in other plants. Target-site resistance associated with a change of valine to isoleucine at residue 219 of the psbA target-site in weeds has previously been reported for Poa annua L selected in diuron-treated grass seed fields, and for Amaranthus powelli S Wats selected in linuron-treated carrot fields. This is the first report of the mutation in herbicide-resistant K scoparia.     

Forb and Invertebrate Response to Treatments for Greater Sage-grouse in Wyoming Big Sagebrush

Treatments in big sagebrush (Artemisia tridentata Nutt.) are often implemented to improve habitat conditions for species such as greater sage-grouse (Centrocercus urophasianus). These treatments aim to increase the availability of forbs and invertebrates critical to juvenile and adult sage-grouse during the breeding season. However, information regarding the response of forbs in treated sagebrush are often conflicting, dependent on the type of sagebrush community treated and time after treatment. In addition, there is little information on the response of invertebrates to treatments, particularly herbicide treatments in Wyoming big sagebrush (A.t. ssp. wyomingensis Beetle & Young) communities. We evaluated the response of forbs and invertebrates in Wyoming big sagebrush that had been mowed or aerially treated with tebuthiuron compared with untreated reference areas. We also compared forb and invertebrate dry matter (DM) between treated plots and locations used by brood-rearing females. Forb and invertebrate DM in mowed and tebuthiuron treatments did not differ from untreated plots up to 4 yr after treatment and were equal to or less than locations used by brood-rearing grouse up to 2 yr after treatment. Our findings corroborate best available science that suggest treating Wyoming big sagebrush may not increase food availability for sage-grouse.     

46%丁噻隆悬浮剂对后茬作物的安全性试验

采用室内盆栽试验的方法,研究了46％丁噻隆悬浮剂土壤残留1个月后对后茬作物生长的影响及安全性.结果表明:在低剂量850 g/hm2(a.i)下,可以安全种植荷兰豆和花生;在中剂量1 700 g/hr2(a.i)下,可以安全种植荷兰豆;在高剂量2 550 g/hm2(a.i)下,菜心、菠菜、青菜和白菜均产生很严重的药害,不能种植,玉米和花生产生严重药害,不能种植,而对荷兰豆产生相对较轻的药害,最好不种植.