Effects of Paclobutrazol and 24-Epibrassinolide on some morphological and biochemical characteristics of Salvia Officinalis under different moisture conditions

Sage (Salvia officinalis L.) is cultivated worldwide especially in Mediterranean regions where the leaves of this herb are widely used in pharmaceutical and food industries. Brassinolides and paclobutrazol are naturally occurring substances which modulate plant growth and development and have been known to improve the crops’ tolerance to biotic and abiotic stresses. The effects of spraying 24-epibrassinolide (BRs: 0.0, 2.5, 3.0, and 3.5 μM), and paclobutrazol (PBZ: 17, 25, and 34 μM), different moisture conditions (I: normal irrigation or non-stress, reduced irrigation or non-stress, reduced irrigation or slight drought, and deficit irrigation or mild drought stress), and interaction effects of BRs × I and PBZ × I on the morphological and biochemical parameters of the S. officinalis were investigated. Reduction in irrigation level led to reduced plant height, the number of branches, shoot fresh and dry weights, root fresh and dry weight while it improved anthocyanin and chlorophyll contents. Spraying BRs enhanced plant height, the number of branches, and anthocyanin and chlorophyll contents with 3 μmolar concentration proving the best treatment. The maximum root fresh and dry weights were associated with combination of the highest irrigation (I3) and applying 17 μM PBZ. The maximum chlorophyll a and total contents were obtained under I3×P3 while the maximum anthocyanin content was observed in BRs2×I3.