Postharvest application of single, multi-walled carbon nanotubes and nanographene oxide improves rose keeping quality
Masoumeh Ahmadi-Majd, Abdolhossein Rezaei Nejad, Sadegh Mousavi-Fard, Dimitrios Fanourakis
Abstract
Keeping quality is frequently terminated by adverse water relations or oxidative stress. This study was designed to evaluate whether postharvest application of single, multi-walled carbon nanotubes and nanographene oxide (SWCNTs, MWCNTs, and NGO respectively) can improve keeping quality in rose, along with the processes involved. Dose-response curves were realised by applying five concentrations of SWCNTs, MWCNTs, and NGO (0–80, 0–80, and 0–2 mg L−1 respectively) either once as a foliar spray or continuously in the holding solution of different rose cultivars. At optimal concentration, CNTs and NGO through either application method extended keeping quality. CNTs improved water balance by promoting water uptake more than water loss, whereas NGO did not. Each nanomaterial at optimal concentration was also employed to assess various parameters underlying keeping quality. CNTs generally enhanced leaf stomatal conductance and transpiration. CNTs and NGO attenuated chlorophyll degradation, electrolyte leakage and lipid peroxidation due to the amplified triggering of both enzymatic and non-enzymatic antioxidants. In conclusion, the extension of keeping quality by postharvest application of CNTs and NGO was characterised by different modes of action. Both upgraded the antioxidant status, while CNTs additionally promoted water relations.Abbreviations: APX, ascorbate peroxidase; CAT, catalase; CNTs, carbon nanotubes; DW, dry weight; FW, fresh weight; GAE, gallic acid equivalent; NGO, nanographene oxide; MDA, malondialdehyde; MWCNTs, multi-walled CNTs; NBT, nitro-blue tetrazolium chloride; POD, peroxidase; RH, relative air humidity; ROS, reactive oxygen species; RUE, rutin equivalent; RWC, relative water content; SOD, superoxide dismutase; SWCNTs, single-walled CNTs.