Potassium Silicate-mediated Physiological and Biochemical Responses in Rosa damascena under Drought

Abstract

Background: Drought stress is a major abiotic factor limiting the physiological and biochemical performance of rose plants. The present study was conducted to evaluate the effect of foliar application of potassium silicate on physiological and biochemical responses of Rosa damascena under water-deficit conditions. Methods: The experiment was conducted in a factorial completely randomized design with three irrigation regimes (100%, 75% and 50% FC) and five potassium silicate concentrations (0, 50, 100, 150 and 200 mg L-1). Various physiological and biochemical parameters such as relative water content (RWC), chlorophyll pigments, membrane stability index (MSI), chlorophyll stability index (CSI), epicuticular wax, proline and phenol contents were analyzed under drought stress conditions. Result: Drought stress significantly reduced RWC, chlorophyll pigments, MSI and CSI, while increasing epicuticular wax deposition, phenol content and proline accumulation. Under 100% field capacity (FC), treated plants showed higher relative water content, chlorophyll pigments, membrane stability index and chlorophyll stability index than untreated plants. Under 75% and 50% FC, drought stress reduced these physiological traits, whereas potassium silicate, particularly at 150 mg L-1, significantly mitigated these adverse effects. Correlation analysis showed positive associations among RWC, chlorophyll pigments, MSI and CSI, whereas proline and phenol contents showed negative associations. The results demonstrated that foliar application of potassium silicate at 150 mg L-1 enhanced drought tolerance in early stages of damask rose.