Velini Edivaldo D, Alves Elza, Godoy Maria C, Meschede Dana K, Souza Reginaldo T, Duke Stephen O
São Paulo State University, Faculty of Agronomic Sciences, Experimental Station Lageado, Laboratory of Weed Science, Botucatu, SP, Brasil CEP 18603-970 PB 237, Brazil.
Pest Manag Sci. 2008 Apr;64(4):489-96. doi: 10.1002/ps.1562.
Glyphosate blocks the shikimic acid pathway, inhibiting the production of aromatic amino acids and several secondary compounds derived from these amino acids. Non-target plants can be exposed to low doses of glyphosate by herbicide drift of spray droplets and contact with treated weeds. Previous studies have reported that low doses of glyphosate stimulate growth, although these data are very limited. The objective of this study was to determine the effects of low glyphosate doses on growth of a range of plant species.
Growth of maize, conventional soybean, Eucalyptus grandis Hill ex Maiden, Pinus caribea L. and Commelia benghalensis L. was enhanced by 1.8-36 g glyphosate ha(-1). Growth of glyphosate-resistant soybean was unaffected by any glyphosate dose from 1.8 to 720 g AE ha(-1). The optimum doses for growth stimulation were distinct for plant species and tissue evaluated. The greatest stimulation of growth was observed for C. benghalensis and P. caribea. Shikimic acid levels in tissues of glyphosate-treated soybean and maize were measured and found to be elevated at growth-stimulating doses.
Subtoxic doses of glyphosate stimulate the growth of a range of plant species, as measured in several plant organs. This hormesis effect is likely to be related to the molecular target of glyphosate, since the effect was not seen in glyphosate-resistant plants, and shikimate levels were enhanced in plants with stimulated growth.
草甘膦阻断莽草酸途径，抑制芳香族氨基酸以及源自这些氨基酸的几种次生化合物的生成。非靶标植物可能会因除草剂喷雾液滴的漂移以及与经处理杂草的接触而暴露于低剂量的草甘膦中。此前的研究报道称，低剂量的草甘膦能刺激生长，不过这些数据非常有限。本研究的目的是确定低剂量草甘膦对一系列植物物种生长的影响。
1.8 - 36克草甘膦/公顷可促进玉米、常规大豆、巨桉、加勒比松和孟加拉鸭跖草的生长。1.8至720克酸当量/公顷的任何草甘膦剂量对耐草甘膦大豆的生长均无影响。促进生长的最佳剂量因所评估的植物物种和组织而异。对孟加拉鸭跖草和加勒比松观察到最大程度的生长促进作用。对经草甘膦处理的大豆和玉米组织中的莽草酸水平进行了测定，发现在促进生长的剂量下其水平升高。
如在多个植物器官中所测定的那样，亚毒性剂量的草甘膦可刺激一系列植物物种的生长。这种兴奋效应可能与草甘膦的分子靶点有关，因为在耐草甘膦植物中未观察到这种效应，且在生长受到刺激的植物中莽草酸水平有所提高。
