Probing the Effect of Salicylic Acid on the Post-harvest Changes in Cordyline fruticosa Using OJIP Chlorophyll Fluorescence Transient Analysis

Abstract

Use of proper postharvest treatment is vital to ensure a longer postharvest life in ornamental plant production including cut-foliage. Although Salicylic Acid (SA) is a promising postharvest treatment, to maintain postharvest quality of many cut foliage species, its direct impact on the photosynthetic process has debatable outcomes as reported by various researchers. In this study, we attempted to investigate the effect of SA on the postharvest performance in cut foliage using OJIP analysis. Two concentrations of SA (100 and 300 mg/L) with a watercontrol were tested with cut-leaves of Cordyline fruticosa var Willy’s gold at room temperature (25±2°C). OJIP parameters, i.e., specific energy fluxes (ABS/RC, TR/RC, ET/RC, and DI/RC), flux ratios (maximum quantum yield of primary photochemistry-φPo), electron transport efficiency (ψo), quantum yield of electron transport (φEo), and performance index (PI) were recorded every other day using a fluorometer (FluorPen FP). Leaf chlorophyll, anthocyanin contents were also determined using spectrophotometry. Data were analysed according to completely randomized design (CRD). The PI increased in both SA treatments up to the 7th day of treatment. SA at 300 mg/L had a significant effect on most of the OJIP parameters, specific fluxes in particular. SA treated leaves exhibited higher on the retention of chlorophyll. Except φPo all other flux ratios were significantly affected by the SA treatment indicating its impact on the photosynthetic apparatus but most probably in retarding the ethylene biosynthesis as reported elsewhere. SA extends the vase life of Cordyline fruticosa cut leaves. Moreover, there is an effect of SA on the photosynthetic machinery; net photosynthesis proved the OJIP results. The underlying mechanism warrants further studies.