Differential Response of Two Biotypes of Goosegrass (Eleusine indica) with Different Sensitivities to Glyphosate to Elevated CO2 Concentrations

• Published in: International journal of agriculture and biology 2015-10, Vol.17 (5), p.976-982
• Main Authors: Zhang, Tai-Jie, Feng, Li, Tian, Xing-Shan, Peng, Chang-Lian, Yang, Cai-Hong, Yue, Mao-Feng
• Format: Article
• Language: English
• Subjects: Eleusine indica
• ISSN: 1560-8530; 1814-9596
• DOI: 10.17957/IJAB/15.0018

To reveal effects of elevated atmospheric CO2 on tolerance to the herbicide glyphosate in the populations of goosegrass (Eleusine indica) known to have resistance to this herbicide, two biotypes of goosegrass, a resistant (R) and a susceptible (S) biotype, were analyzed after exposed to ambient (400 mol mol-1) and elevated CO2 (800 mol mol-1) for 25 d. The results showed that elevated CO2 had little effect on growth of both biotypes. At elevated CO2, shoot biomass of R biotype was statistically lower than of S biotype (Pless than 0.5). The dose-response analysis showed that glyphosate tolerance was reduced by 60% in R biotype exposed to elevated CO2 while it was slightly increased in S biotype. Elevated CO2 also had more adverse effects on photosynthetic capacity of R biotype than S biotype. As a result, maximum rate of net photosynthesis (Amax) and carboxylation efficiency (CE) under elevated CO2 in R biotype were significantly lower than in S biotype (Pless than 0.5). These results indicate that elevated atmospheric CO2 can lead to a compromise in glyphosate tolerance of R biotype associated with poor photosynthetic characteristics, and thus will affect weed management involved with herbicide resistance in prospective agricultural systems.