Multi-microscopy techniques combined with FT-IR spectroscopy reveals the histological and biochemical causes leading to fruit texture difference in oriental melon (Cucumis melo var. Makuwa Makino)

Abstract

Multi-microscopy techniques and Fourier transform infrared (FT-IR) spectroscopy were used in this study to investigate the intrinsic causes leading to fruit texture difference between two cultivars of oriental melon ‘HDB’ (crisp) and ‘HPM’ (mealy). On the histological aspect, orderly arranged regular-shaped cells with tissue natural fracture pattern showed cell rupture in ‘HDB’ versus loosely arranged irregular-shaped cells with tissue natural fracture pattern showed cell-to-cell separation in ‘HPM’ of sarcocarp are histological causes for crisp and mealy fruit texture, respectively. On the biochemical aspect, FT-IR spectra (4000–850 cm−1) of sarcocarp tissue cell wall materials (CWM) happened a dramatic change at the mature stage in ‘HPM’, but not in ‘HDB’. Insightly, the lower de-methyl-esterified homogalacturonan (HG) abundance with higher water-soluble pectin (WSP) ratio and lower hemicellulose (HC) content contribute a poor intercellular adhesion in ‘HPM’ middle lamella (ML) at the mature stage compared to ‘HDB’.