采前钙处理对黄金梨果顶硬化果实贮藏特性及PpEXPA2基因表达的影响

为探究采前钙处理对黄金梨果顶硬化果实的影响，以黄金梨正常果实和果顶硬化果实为试材，对部分果顶硬化果实进行采前喷钙处理，分别测定果实的贮藏特性和PpEXPA2基因表达量等指标。结果表明：2 ℃贮藏期间，正常果实、CaCl2处理果实及果顶硬化果实萼端的硬度、粘性、弹性、内聚性和咀嚼性均呈先升高后降低趋势，CaCl2处理果实萼端及柄端的硬度和咀嚼性均明显低于果顶硬化果实；正常果实失重率最高，其次为CaCl2处理果实；CaCl2处理降低了果顶硬化果实的腐烂率，并抑制了果实的呼吸强度。贮藏180 d，CaCl2处理果实的腐烂率和呼吸强度分别较果顶硬化果实降低了18.87%和59.70%；采收初期，PpEXPA2基因在果顶硬化果实中的表达明显高于正常果实和果顶硬化果实，随后下降，而正常果实和CaCl2处理果实中PpEXPA2基因的相对表达量均随贮藏时间逐渐升高，采前CaCl2处理抑制了该基因的表达。
In order to investigate the influence of pre-harvest calcium treatment on the hard-end Whangkeumbae (Pyrus pyrifolia.Nakai.) pear fruits, normal fruits and hard-end fruits were used as test materials. Some of the hard-end pear fruits were sprayed with CaCl2 solutions before harvest, and the fruit storage characteristics, gene expression level of PpEXPA2, and other indicators were determined. The results showed that during storage at 2 ℃, the firmness, adhesiveness, springiness, cohesiveness, and chewiness of the calyx-end area of normal fruit, CaCl2-treated fruit and hard-end fruit showed a downward trend after the initial increase. The firmness and chewiness in both stem end and calyx end areas of CaCl2-treated fruit were lower than those of hard-end fruit. The weight loss rate was highest in normal fruit, followed by in CaCl2-treated fruit. CaCl2 treatment reduced the rot rate of hard-end fruit and inhibited the respiration rate of the fruits. After 180 days of storage, the rot rate and respiration rate of CaCl2-treated fruit were decreased by 18.87% and 59.70%, respectively, compared with hard-end fruit. During the early stage of the postharvest period, the relative expression level of PpEXPA2 in hard-end fruit was significantly higher than those in normal fruit and CaCl2-treated fruit and was then decreased. The relative expression levels of PpEXPA2 in normal fruit and CaCl2-treated fruit gradually increased during the storage period. Pre-harvest CaCl2 treatment may inhibit the gene expression of PpEXPA2.