Anatomical Studies of Stone Cells in Fruits of Four Different Pear Cultivars
Stone cells are one of the most important factors affecting the fruit quality of pears (Pyrus bretschneideri Rehder, P. communis L., P. pyrifolia (Burm. f.) Nakai and P. bretschneideri × communis). Sections of pear fruits were examined during fruit development to analyze the content and diameter of stone cells in four different pear cultivars. At maturity, the abundance of stone cells in Dangshansuli pears was the highest at the peel, followed by core and flesh. In contrast, the stone cells of three other cultivars were more abundant at the core compared to the peel and flesh, and the percentage of stone cells with a diameter greater than 80 μm was significantly lower than in Dangshansuli. In addition, the initiation of stone cell formation in Dangshansuli pears was at 10 days after full bloom (DAFB) and peaked at 7 weeks after flowering. Contrarily in Whangkeumbae, Bartlett and Yuluxiangli pears, stone cells were initiated at 15 DAFB and peaked 4–6 weeks after flowering. In conclusion, the higher density, larger diameter, and radial distribution of stone cells in Dangshansuli pears resulted in a coarse texture compared to Whangkeumbae, Bartlett, and Yuluxiangli pears. These findings can help to improve the visualization of stone cells in pear fruit and help to improve the fruit quality by reducing the formation of stone cells.