Alcántara de la Cruz Ricardo, Barro Francisco, Domínguez-Valenzuela José Alfredo, De Prado Rafael
Department of Agricultural Chemistry and Edaphology, University of Cordoba, E-14071, Cordoba, Spain.
Institute for Sustainable Agriculture, Spanish National Research Council (IAS-CSIC), E-14004, Córdoba, Spain.
Plant Physiol Biochem. 2016 Jan;98:72-80. doi: 10.1016/j.plaphy.2015.11.009. Epub 2015 Nov 30.
In recent years, glyphosate-tolerant legumes have been used as cover crops for weed management in tropical areas of Mexico. Mexican cologania (Cologania broussonetii (Balb.) DC.) is an innate glyphosate-tolerant legume with a potential as a cover crop in temperate areas of the country. In this work, glyphosate tolerance was characterized in two Mexican cologania (a treated (T) and an untreated (UT)) populations as being representatives of the species, compared in turn to a glyphosate-susceptible hairy fleabane (S) (Conyza bonariensis (L.) Cronq.) population. Experiments revealed that T and UT Mexican cologania populations had a higher tolerance index (TI), and a lower shikimic acid accumulation and foliar retention than the hairy fleabane S population. Absorption and translocation, leaf morphology and metabolism studies were only carried out in the Mexican cologania T population and the hairy fleabane S population. The latter absorbed 37% more (14)C-glyphosate compared to the Mexican cologania T at 96 h after treatment (HAT). Mexican cologania T translocated less herbicide from the treated leaf to the remainder of the plant than hairy fleabane S. The Mexican cologania T presented a greater epicuticular wax coverage percentage than the hairy fleabane S. This morphological characteristic contributed to the low glyphosate absorption observed in the Mexican cologania. In addition, the Mexican cologania T metabolized glyphosate mainly into AMPA, formaldehyde and sarcosine. These results indicate that the high glyphosate tolerance observed in Mexican cologania is mainly due to the poor penetration and translocation of glyphosate into the active site, and the high glyphosate degradation into non-toxic substances.
近年来，耐草甘膦豆科植物已被用作墨西哥热带地区杂草治理的覆盖作物。墨西哥哥洛加纳豆（Cologania broussonetii (Balb.) DC.）是一种天然耐草甘膦豆科植物，在该国温带地区有作为覆盖作物的潜力。在这项研究中，以两个墨西哥哥洛加纳豆种群（一个经过处理（T），一个未处理（UT））作为该物种的代表来表征其草甘膦耐受性，同时与对草甘膦敏感的苏门白酒草（S）（Conyza bonariensis (L.) Cronq.）种群进行比较。实验表明，与苏门白酒草S种群相比，墨西哥哥洛加纳豆T和UT种群具有更高的耐受性指数（TI）、更低的莽草酸积累和叶片滞留率。仅在墨西哥哥洛加纳豆T种群和苏门白酒草S种群中进行了吸收与转运、叶片形态及代谢研究。处理后96小时（HAT），苏门白酒草S吸收的¹⁴C - 草甘膦比墨西哥哥洛加纳豆T多37%。墨西哥哥洛加纳豆T从处理叶片向植株其他部位转运的除草剂比苏门白酒草S少。墨西哥哥洛加纳豆T的表皮蜡覆盖百分比高于苏门白酒草S。这一形态特征导致墨西哥哥洛加纳豆草甘膦吸收量较低。此外，墨西哥哥洛加纳豆T将草甘膦主要代谢为氨甲基膦酸、甲醛和肌氨酸。这些结果表明，墨西哥哥洛加纳豆中观察到的高草甘膦耐受性主要归因于草甘膦向活性位点的渗透和转运较差，以及草甘膦向无毒物质的高降解率。
