Effects of light-dependent herbicides on growth and physiology of Salvia officinalis

Abstract Background: Salvia officinalis a medicinal plant which is severely affected by weeds competition. Objective: The objective of this study was to determine the growth and physiological responses of S. officinalis to some light-dependent herbicides. Methods: A factorial experiment was conducted to determine the effects of oxadiargyl (T), bentazon (B), oxyfluorfen (O), metribuzin (M), phenmedipham+desmedipham (P) at 0.75 (1), 1 (2) and 1.25 (3) rates on growth and physiological parameters of S. officinalis. Results: All herbicides initially caused visual injury to S. officinalis. SPAD values were decreased by all herbicide treatments except for low rate of phenmedipham+desmedipham and oxadiargyl. The relative leaf water content (RLWC) decreased following herbicide treatments except in P1, P2, B1, and B2. Membrane stability index decreased by herbicide treatments however there were no differences among control and P1, P2, B1, B2, O1, O3, M3, T1, T2, and T3. All rates of oxyfluorfen and oxadiargyl, P1, B1 and B2 had no marked effect on the maximum quantum efficiency of PSII (Fv/Fm). Plant growth was not affected by herbicide treatments probably due to the recovery of the plants at the end of the experiment excepting for metribuzin. Essential oil content increased as the herbicide rate increased based on herbicide type. Conclusions: The results showed that S. officinalis had the ability to recover over time depending on the herbicide type and rate. Results showed that phenmedipham+desmedipham and bentazon are suitable and metribuzin unsuitable herbicides for weeds selective control in S. officinalis.

摘要 研究背景：鼠尾草（Salvia officinalis）是一种药用植物，其生长会受到杂草竞争的严重影响。
研究目的：本研究旨在探究鼠尾草对几种光敏型除草剂（light-dependent herbicides）的生长与生理响应。
研究方法：采用析因试验设计，设置噁草灵（oxadiargyl, T）、苯达松（bentazon, B）、乙氧氟草醚（oxyfluorfen, O）、嗪草酮（metribuzin, M）、苯草醚+双苯胺灵（phenmedipham+desmedipham, P）共5种除草剂，每种药剂设置0.75（记为1）、1（记为2）、1.25（记为3）倍施用剂量，分析不同处理对鼠尾草生长及生理指标的影响。
研究结果：所有除草剂处理初期均会导致鼠尾草出现可见药害。除低剂量苯草醚+双苯胺灵与噁草灵处理组外，其余各除草剂处理均降低了植株SPAD值。除P1、P2、B1及B2组外，其余除草剂处理均降低了植株相对叶片含水量（relative leaf water content, RLWC）。除草剂处理会降低膜稳定性指数（membrane stability index, MSI），但对照组与P1、P2、B1、B2、O1、O3、M3、T1、T2及T3组间无显著差异。所有剂量的乙氧氟草醚与噁草灵处理，以及P1、B1与B2组对PSII最大光化学量子效率（maximum quantum efficiency of PSII, Fv/Fm）无显著影响。除嗪草酮处理组外，其余除草剂处理未对植株生长造成显著影响，推测原因为实验末期植株完成了药害恢复。基于除草剂类型的差异，精油含量随药剂施用剂量升高而上升。
研究结论：结果表明，鼠尾草的药害恢复能力取决于除草剂类型与施用剂量。苯草醚+双苯胺灵与苯达松可作为鼠尾草田间杂草选择性防控的适宜除草剂，而嗪草酮则不适用于该场景。