Cui Zhenhua, Sun Haoqi, Lu Yuqin, Ren Lixin, Xu Xinrui, Li Dingli, Wang Ran, Ma Chunhui
College of Horticulture, Qingdao Agricultural University, Qingdao, China.
Engineering Laboratory of Genetic Improvement of Horticultural Crops of Shandong Province, Qingdao, China.
Front Plant Sci. 2022 Jan 31;13:815283. doi: 10.3389/fpls.2022.815283. eCollection 2022.
Fruit pedicel is the bridge linking the parent tree and the fruit, which is an important channel for water and nutrients transport to the fruit. The genetic specificity determines the characteristics of the pedicel and the fruit, but the relationship between the pedicel structure and the fruit characteristics is unexplored. Combining the investigation of fruit characteristics, the statistical analysis of the pedicel structural properties, and the 2D and 3D anatomical observation of the pedicel, this study found distinctive contributions of the pedicel elements to the fruit characteristics in four pear species. The European pear (Conference) showed distinct fruit shape index and pedicel structural properties compared with the oriental pears (Akizuki, Yali, and Nanguoli). The fruit size positively correlated with pedicel length, fiber area, pedicel diameter, the area percentage of the cortex, and the area percentage of phloem; however, fruit firmness and soluble solids concentration are showed a stronger positive correlation with xylem area, pith area, the area percentage of xylem, the area percentage of sieve tube, and the area percentage of pith. Pedicel elements, including pith, fiber, and cortex, likely play a certain role in the fruit growth due to the variations of their characteristics demonstrated in the four pear species. The porosity, the ratio of the surface area to the volume, and the spatial arrangement of the vessels showed significant variations across the pear species, indicating the distinction of the hydraulic conductance of the pedicels. Our findings provided direct evidence that pedicel structural elements contributed distinctively to the fruit characteristics among pear species.
果梗是连接母树和果实的桥梁，是水分和养分输送到果实的重要通道。遗传特异性决定了果梗和果实的特征，但果梗结构与果实特征之间的关系尚未得到探索。本研究结合果实特征调查、果梗结构特性的统计分析以及果梗的二维和三维解剖观察，发现了四种梨品种中果梗各成分对果实特征的独特贡献。西洋梨（康佛伦斯）与东方梨（秋月、鸭梨和南果梨）相比，果实形状指数和果梗结构特性明显不同。果实大小与果梗长度、纤维面积、果梗直径、皮层面积百分比和韧皮部面积百分比呈正相关；然而，果实硬度和可溶性固形物含量与木质部面积、髓部面积、木质部面积百分比、筛管面积百分比和髓部面积百分比呈更强的正相关。由于在四种梨品种中观察到果梗各成分（包括髓部、纤维和皮层）的特征存在差异，它们可能在果实生长中发挥一定作用。不同梨品种的孔隙率、表面积与体积之比以及导管的空间排列存在显著差异，表明果梗的导水率有所不同。我们的研究结果提供了直接证据，表明果梗结构成分在不同梨品种中对果实特征有独特贡献。
