Organ-Specific Cuticular Wax Composition across Epicuticular and Intracuticular Layers in Leaves and Petals of Phalaenopsis ‘Mantefon’

The deterioration of indoor air quality is a major environmental and public health concern, and interactions between particulate matter (PM) and plant surfaces have been recognized in indoor horticulture.Because PM deposition and retention are influenced by cuticular wax chemistry and by surface microstructures, we quantified cuticular wax compositions in the leaves and petals of Phalaenopsis 'Mantefon' by separately extracting epicuticular and intracuticular waxes (EW, IW).The total wax load was substantially higher in the leaves (73.067 gcm -2 ) than in the petals (22.481 gcm -2 ), primarily due to strong alkane accumulation in the leaf EW and IW (41.971 and 26.501 gcm -2 , respectively).In the petals, the total wax loads were comparable between EW (11.430 gcm -2 ) and IW (11.051 gcm -2 ), although the compound class allocation differed markedly depending on the layer.Petal EW was dominated by fatty acids (60.7%), whereas petal IW exhibited increased contributions of alkanes (47.4%) and primary alcohols (20.1%), with a detectable triterpenoid fraction observed only in the petals.Carbon chain length distributions further distinguished organs and layers, with petals showing shorter-chain alkanes (C17 to C24), fatty acids extending to longer chains with C28 predominance, and primary alcohols enriched in petal IW with major homologs at C32 and C34.Scanning electron microscopy revealed abundant wax crystals on leaf surfaces but sparse crystalline structures on petals, consistent with the contrasting chemical organizations.Overall, these results demonstrate clear organ-and layer-dependent differences in cuticular wax loads and compositions in P. 'Mantefon', providing a quantitative reference dataset for future functional studies under indoor relevant conditions.