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.