摘 要

‘红哨兵’海棠品种是集观花观果于一身的优良品种，其果实亮红色，口感优良，商品价值高，具有很高的研究价值，本研究以‘红哨兵’海棠果实为试验材料，通过采用浓度为1 μL/L的1-MCP熏蒸处理，对其货架期海棠果实硬度、维生素C含量、果肉POD活性、呼吸强度和乙烯释放量等指标进行定期取样测定研究，并对货架期各指标进行相关性和主成分分析，旨在为今后延长海棠果实货架期提供理论依据及参考价值。结果表明如下：

1. 在果实硬度方面，随货架期延长果实硬度会显著下降，对照组（CK）在第15 d下降为原来的50 %，而经1-MCP处理后的海棠果实硬度推迟10 d在货架期第25 d下降为原来的50 %，可见1-MCP处理有效减缓了海棠果实的软化。
2. 在果实维生素C含量方面，货架期间果实内维生素C会被不断降解，但1-MCP处理组有效减缓海棠果实中维生素C含量的降解，且货架期间维生素C含量始终高于对照组（CK）。
3. 在果实呼吸强度方面，货架期间两组海棠果实均呈现先上升后下降的趋势，对照组（CK）在货架期15 d达到呼吸高峰，而1-MCP处理组推迟5 d在货架期20 d达到呼吸高峰，且总体变化趋势也比较缓和，减少了呼吸消耗。
4. 在乙烯释放量方面，两组海棠果实的乙烯释放量变化与呼吸强度变化基本一致，均呈现先上升后下降的趋势，对照组（CK）在货架期15 d达到乙烯释放高峰，1-MCP处理组推迟5 d在货架期20 d出现乙烯释放高峰，且1-MCP处理组乙烯释放量始终低于对照组（CK），有效减缓了海棠果实的后熟现象。
5. 在果肉POD活性方面，货架期间两组海棠果实均呈现先下降后上升再下降的趋势，并在货架期第15 d达到各自的峰值，且1-MCP处理组果肉POD活性是对照组（CK）的2.86 倍，在货架期15 d后，对照组POD活性迅速下降至无法读数，而1-MCP处理组的果实POD活性能够保持在一个较高的水平，提高果实的抗氧化能力，有效减缓了货架期海棠果实的腐烂。
6. 对海棠果实货架期指标的相关性分析可得，果实硬度和果实维生素C含量呈极显著的正相关（Plt;0.01），果实呼吸强度和乙烯释放量呈极显著正相关（Plt;0.01）。
7. 对海棠果实5个货架期指标主成分分析得，其中特征值大于1的前2个主成分累积方差贡献率达到98.567 %（代表1-MCP处理货架期果实生理指标的绝大部分信息），把原有5个指标综合为2个相互独立的因子，同时PC₁、PC₂的方差贡献率分别为75.118 %和23.449 %。

PC₁主要代表1-MCP处理货架期‘红哨兵’海棠果实生理指标的果实硬度、维生素C含量、果实呼吸强度和乙烯释放量，其中前两个指标与PC₁间呈正相关，后两个指标与PC₁呈负相关；PC₂主要代表生理指标的果肉POD活性，与PC₂间呈正相关。可明显看出在探究1-MCP处理货架期海棠果实对生理指标的影响中，受1-MCP处理后的影响相对较大的生理指标。

综上所述，对照组(CK)‘红哨兵’海棠果实在货架期15 d左右即失去其商品价值，而1-MCP处理后的海棠果实可延长其商品价值至货架期20 d之后，表明1-MCP处理后的海棠果实能有效延缓果实衰老，保持海棠果实一定营养成分和良好品质。同时试验通过对‘红哨兵’海棠果实货架期5 个指标进行相关性分析和主成分分析相结合的方法，进一步探究货架期长短对海棠果实品质变化和各生理指标的变化的影响，为今后研究海棠果实的采后保鲜和货架期贮藏提供相关的理论依据和实际参考。

关键词：海棠果实；货架期；1-MCP处理；品质变化；生理指标

Effects of shelf life on quality changes and physiological indexes of Crabapple (Malus spp.)

ABSTRACT

The M. 'Red Sentinel' variety is an excellent variety of flowers and fruit. Its fruit is bright red, with good taste and high commodity value. It has high research value. This study used M. 'Red Sentinel' fruit as test material. By using 1-MCP fumigation treatment at a concentration of 1 μL/L, the indexes of Crabapple (Malus spp.) firmness, vitamin C content, pulp POD activity, respiration intensity and ethylene release amount were periodically sampled and studied, and the shelf life was observed. Correlation and principal component analysis were carried out for each indicator, aiming to provide theoretical basis and reference value for extending the shelf life of Crabapple (Malus spp.) in the future. The results are as follows:

(1) In terms of fruit firmness, the fruit firmness decreased significantly with the shelf life, and the control group (CK) decreased to 50% on the 15th day, while the crabapple hardness after 1-MCP treatment was delayed 10 days on the shelf. On the 25th day, it decreased to 50%. It can be seen that 1-MCP treatment effectively slowed the softening of crabapple.

(2) In the vitamin C content of fruits, vitamin C in the fruit during the shelf period was continuously degraded, but the 1-MCP treatment group effectively slowed the degradation of vitamin C content in the fruit, and the vitamin C content during shelf was always higher than that of the control group (CK). ).

(3) In terms of fruit respiration intensity, the fruit of the two groups of crabapple increased first and then decreased during the shelf period. The control group (CK) reached the respiratory peak 15 days after the shelf life, while the 1-MCP treatment group delayed the shelf life by 5 days. The respiratory peak was reached in 20 days, and the overall trend was also moderated, reducing respiratory consumption.

4) In terms of ethylene release, the changes in ethylene release and the change in respiration intensity of the two groups of crabapples were basically the same, which showed a trend of increasing first and then decreasing. The control group (CK) reached the peak of ethylene release at the shelf life of 15 days. The -MCP treatment group delayed the release of ethylene at the shelf life of 20 days, and the ethylene release in the 1-MCP treatment group was always lower than that of the control group (CK), so that the Crabapple could maintain good quality and delay aging.

(5) In the POD activity of flesh, the fruit of the two groups of crabapple decreased first, then increased and then decreased during the shelf period, and reached their peak on the 15th day of the shelf life, and the POD activity of the flesh in the 1-MCP treatment group was the control group. 2.86 times of (CK), after 15 days of shelf life, the POD activity of the control group decreased rapidly to the inability to display readings, while the fruit POD activity of the 1-MCP treatment group could be maintained at a higher level, improving the antioxidant capacity of the fruit. It effectively slowed the decay of the fruit of the sea bream during the shelf life.

(6) Correlation analysis of shelf life index of Crabapple showed that there was a significant positive correlation between fruit firmness and vitamin C content (Plt;0.01), and there was a significant positive correlation between fruit respiration intensity and ethylene release (Plt; 0.01).