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

Sage (Salvia officinalis L.) is cultivated worldwide especially in Mediterranean regions in which 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 events and have been known to improve the crops tolerance to biotic and abiotic stresses. The effects of spraying of 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 leaves were investigated. Reduction in level irrigation led to decrease plant height, the numbers of branches, fresh herbal and dry weight, fresh roots and dry weight while it improved content of anthocyanin and chlorophyll. The spraying of BRs enhanced plant height, the numbers of branches, anthocyanin and chlorophyll with 3 µmolar concentration proving the best. The most values of fresh root and dry weight was associated with combination of the highest irrigation (I3) and applying 17µM PBZ. Highest value of chlorophyll a and total reached in I3×P3. Maximum content of anthocyanin and chlorophyll b were observed in BRs2×I3 and BRs2×P2 respectively. Finally, we can be concluded that the foliar spraying of BRs and PBZ improve most of the features of sage under deficit irrigation.