The foliar retention, absorption, translocation, and diffusion of glyphosate in glyphosate resistant-(R) and susceptible (S)-Palmer amaranth populations from seed collected in Georgia in 2007 were examined. The R popu...The foliar retention, absorption, translocation, and diffusion of glyphosate in glyphosate resistant-(R) and susceptible (S)-Palmer amaranth populations from seed collected in Georgia in 2007 were examined. The R population of Palmer amaranth had an elevated copy number of the EPSPS gene conferring the mechanism of resistance. When applications of 14C-glyphosate to a single leaf followed entire plant treatment with glyphosate, the distribution percentages were similar for R and S for the above and below treated leaves when harvested at 1, 6, 12, 24, and 48 hours after treatment (HAT). There were initially no differences between R and S at 1 HAT with an average of 8% absorption for both biotypes. However, data indicated that glyphosate absorption increased for R-Palmer amaranth reaching 41% within 6 HAT and was significantly different (P = 0.01) from the 28% absorbed by S-Palmer amaranth. Glyphosate resistant and susceptible Palmer amaranth averaged 44% 14C-glyphosate absorption by 24 HAT. There were no differences for 14C-glyphosate Bq/mg of plant tissue between R and S for the above the treated leaf and below the treated leaf portions of plants at 1, 6, 12, 24, or 48 HAT. However, root accumulation of 14C-glyphosate in plant tissue was significantly greater by 12 HAT for the roots of R (1.21 Bq/mg) than for S (0.51 Bq/mg). The treated leaf of the R-Palmer amaranth plants exhibited greater translocation of 14C-glyphosate in Bq/mg of tissue than the susceptible over time, indicating no detrimental effect or cost of fitness due to EPSPS gene amplification. Additionally, there were no differences in glyphosate retention in leaf discs assays between R and S biotypes. In spite of an average of 6.5 Bq efflux out of R and S leaf discs after 15 minute, only 0.4 Bq was retained after 150 minutes. Glyphosate was not retained over time in the leaf discs for R and S, and there were no biotype differences within bathing times. However, the rate of efflux (the slope of the curves) was greater for the R biotype. These data support the reported gene amplification non-target site glyphosate resistance mechanism in Palmer amaranth.展开更多
我国有记录的苋属植物20余种,主要为外来杂草。苋属植物形态相近,常被误鉴。作者从送检的误鉴的标本中发现2个新外来种,根据拉丁文名种加词释义,分别命名为鲍氏苋( Amaranthus powellii S. Watson)和布氏苋( A. bouchonii Thell.)。鲍...我国有记录的苋属植物20余种,主要为外来杂草。苋属植物形态相近,常被误鉴。作者从送检的误鉴的标本中发现2个新外来种,根据拉丁文名种加词释义,分别命名为鲍氏苋( Amaranthus powellii S. Watson)和布氏苋( A. bouchonii Thell.)。鲍氏苋和布氏苋形态相近,分别产自美国西南部和欧洲,雌雄同株,具3~5雌花花被片,花被片不等长,等于或短于胞果,胞果开裂或不开裂。鲍氏苋和布氏苋可通过花被片数目和形态、胞果是否开裂、苞片大小相区分。该文还提供了鲍氏苋和布氏苋的中文形态描述及彩色图片,并对其分布、生境和危害状况进行了报道。展开更多
文摘The foliar retention, absorption, translocation, and diffusion of glyphosate in glyphosate resistant-(R) and susceptible (S)-Palmer amaranth populations from seed collected in Georgia in 2007 were examined. The R population of Palmer amaranth had an elevated copy number of the EPSPS gene conferring the mechanism of resistance. When applications of 14C-glyphosate to a single leaf followed entire plant treatment with glyphosate, the distribution percentages were similar for R and S for the above and below treated leaves when harvested at 1, 6, 12, 24, and 48 hours after treatment (HAT). There were initially no differences between R and S at 1 HAT with an average of 8% absorption for both biotypes. However, data indicated that glyphosate absorption increased for R-Palmer amaranth reaching 41% within 6 HAT and was significantly different (P = 0.01) from the 28% absorbed by S-Palmer amaranth. Glyphosate resistant and susceptible Palmer amaranth averaged 44% 14C-glyphosate absorption by 24 HAT. There were no differences for 14C-glyphosate Bq/mg of plant tissue between R and S for the above the treated leaf and below the treated leaf portions of plants at 1, 6, 12, 24, or 48 HAT. However, root accumulation of 14C-glyphosate in plant tissue was significantly greater by 12 HAT for the roots of R (1.21 Bq/mg) than for S (0.51 Bq/mg). The treated leaf of the R-Palmer amaranth plants exhibited greater translocation of 14C-glyphosate in Bq/mg of tissue than the susceptible over time, indicating no detrimental effect or cost of fitness due to EPSPS gene amplification. Additionally, there were no differences in glyphosate retention in leaf discs assays between R and S biotypes. In spite of an average of 6.5 Bq efflux out of R and S leaf discs after 15 minute, only 0.4 Bq was retained after 150 minutes. Glyphosate was not retained over time in the leaf discs for R and S, and there were no biotype differences within bathing times. However, the rate of efflux (the slope of the curves) was greater for the R biotype. These data support the reported gene amplification non-target site glyphosate resistance mechanism in Palmer amaranth.
文摘我国有记录的苋属植物20余种,主要为外来杂草。苋属植物形态相近,常被误鉴。作者从送检的误鉴的标本中发现2个新外来种,根据拉丁文名种加词释义,分别命名为鲍氏苋( Amaranthus powellii S. Watson)和布氏苋( A. bouchonii Thell.)。鲍氏苋和布氏苋形态相近,分别产自美国西南部和欧洲,雌雄同株,具3~5雌花花被片,花被片不等长,等于或短于胞果,胞果开裂或不开裂。鲍氏苋和布氏苋可通过花被片数目和形态、胞果是否开裂、苞片大小相区分。该文还提供了鲍氏苋和布氏苋的中文形态描述及彩色图片,并对其分布、生境和危害状况进行了报道。
