Water availability is a concern for agricultural production and sustainability, escalating the need for an efficient weed control. Weeds are in direct competition with crops for water and its unsuccessful control risks water management across the crop season. However, little is known regarding the impact of herbicide on weed water use behavior. Thus, the objective of this study was to unveil the effect of glyphosate doses on Merremia aegyptia (L.) Urb. water transpiration, water use efficiency (WUE), and intrinsic water use efficiency (iWUE). Two greenhouse studies were conducted using the troublesome weed hairy woodrose (M. aegyptia) in four glyphosate doses (1.4; 15; 111; and 740 g a.e. ha⁻¹) plus an untreated control. Water transpiration was measured in a 3-day-interval until 21 days after treatment (DAT), determining WUE based on its dry biomass and water use. iWUE was determined at 21 DAT through IRGA analysis. Glyphosate label dose (740 g a.e. ha⁻¹) effectively reduced water transpiration 3 DAT and ceased whole water transpiration by 12 DAT. Lower doses (111 and 15 g a.e. ha⁻¹) reduced 39 and 20% of water transpiration, in comparison to the untreated control, and increased its iWUE. Therefore, label dose application of glyphosate successfully controlled hairy woodrose and ceased its water transpiration.

水的可用性是农业生产和可持续性的一个问题，因此对有效控制杂草的需求不断增加。杂草与作物直接竞争水资源，其不成功的控制会给整个作物季节的水资源管理带来风险。然而，关于除草剂对杂草水分利用行为的影响知之甚少。因此，本研究的目的是揭示草甘膦剂量对Merremia aegyptia (L.) Urb的影响。水分蒸腾、水分利用效率 (WUE) 和固有水分利用效率 (iWUE)。使用四种草甘膦剂量（1.4；15；111；和 740 g ae ha ⁻¹ ）的麻烦杂草毛木蔷薇（M. aegyptia ）进行了两项温室研究) 加上未经处理的控制。以 3 天为间隔测量水蒸腾，直到处理后 21 天 (DAT)，根据其干生物量和用水量确定 WUE。iWUE 通过 IRGA 分析在 21 DAT 时确定。草甘膦标签剂量（740 g ae ha ^-1）有效地减少了 3 DAT 的水蒸腾，并在 12 DAT 时停止了整个水的蒸腾。与未处理的对照相比，较低剂量（111 和 15 g ae ha ^{-1 ）减少了 39% 和 20% 的水蒸腾，并增加了 iWUE。}因此，草甘膦的标签剂量应用成功地控制了毛木蔷薇并停止了它的水分蒸腾。