磷酸二氢钾对脐橙陷痕果发生及果皮细胞壁代谢的影响

 研究‘卡拉卡拉’（Citrus sinensis Osbeck‘Cara Cara’）和‘纽荷尔’（Citrus sinensis Osbeck ‘Newhall’）脐橙果实膨大期叶面喷施钾肥（0.2% KH2PO4）后，成熟期陷痕果发生率、果皮细胞壁物质成分、细胞壁代谢相关酶活性的变化规律及其关系。结果表明，KH2PO4处理对卡拉卡拉脐橙和纽荷尔脐橙的果皮厚度、硬度及其均匀度有不同程度的影响，卡拉卡拉脐橙的陷痕果发生率显著降低。纽荷尔脐橙的细胞壁代谢以及果皮力学性能受KH2PO4的影响较小，陷痕果率无显著变化。果皮果胶酶、纤维素酶、木聚糖酶、过氧化物酶活性的降低可以减缓果皮原果胶、纤维素和半纤维素成分的降解，降低果实成熟过程中果皮软化的速度，减少陷痕果的发生。

Effects of Spraying KH_2PO_4 on Cell-wall Metalbolism of Pericarp and Pitting Fruit Rate in Navel Orange

Based on the different incidence of pitting fruit，two navel orange cultivars ‘Cara cara’ navel orange（Citrus sinensis Osbeck‘Cara Cara’）and ‘Newhall’ navel orange（Citrus sinensis Osbeck ‘Newhall’）were used to research on cell wall composition，related enzymes in cell wall metabolism of peel and pitting fruit rate with the KH2PO4 foliar application during ripening. The results showed that the difference existed in the peel thickness，hardness and homogeneity between‘Cara Cara’and‘Newhall’navel orange with the KH2PO4 spraying，the pitting fruit rate of‘Cara Cara’navel orange was significantly decreased. There was a few effects on cell-wall metalbolism and pericarp character in‘Newhall’than‘Cara Cara’navel orange，and there have no significant difference in pitting fruit rate of‘Newhall’between KH2PO4 foliar application and control. The decreasing of polygalacturonase（PG），cellulose（CX），xylanase（Xyn），and peroxidase（POD）activities maybe low the decomposition of protopectin，hemicellulose and cellulose，increase peel hardness and thickness，low pitting fruit incidence.