Effect of calcium nitrate on muskmelon （cucumis melon l.） softness and relative physiological parameters | 硝酸钙对网纹甜瓜果实软化及其相关生理因素的影响

Chinese. 研究硝酸钙对网纹甜瓜果实软化及其相关生理因素的影响,探讨延长网纹甜瓜货架期的调控措施,为生产上利用钙来延长网纹甜瓜的最佳食用期和货架寿命提供理论依据,并为进一步探明钙减缓果实成熟衰老的机制奠定基础。以网纹甜瓜果实圆片为材料,研究了不同浓度硝酸钙（1,3,5mmol・L. 1）处理4,8,12,16,20,24h情况下,甜瓜果实软化及其相关生理指标的变化。结果表明：硝酸钙可明显降低甜瓜果实软化速度,具有提高果实硬度,降低果肉乙烯释放量、呼吸速率以及多聚半乳糖醛酸酶（PG）、果胶甲酯酶（PE）、羧甲基纤维素钠酶（CMC-Na）活性的作用。与对照（6.09～6.81kg・cm. 2）相比,钙处理果肉硬度提高0.22～1.24kg・cm. 2,但不同处理浓度和处理时间对果实软化的作用效果存在一定差异。5mmol・L. 1的硝酸钙处理较1mmol・L. 1和3mmol・L. 1处理具有更明显地抑制甜瓜果肉呼吸速率、乙烯释放量以及PG、PE和CMC-Na活性的作用,从而对果肉软化的抑制效果更显著,前者的硬度比后者高0.02～0.34kg・cm. 2。硝酸钙处理4h可明显提高果实硬度,降低果肉乙烯释放量、呼吸速率并抑制PG、PE和CMC-Na的活性;处理12h对以上各软化相关生理指标的抑制效果最强,当处理24h时果肉的乙烯释放量、PE和CMC-Na活性均有所升高,但是仍与对照存在较大差异。5mmol・L. 1硝酸钙处理12h具有较好地减缓网纹甜瓜果实软化的作用。[著者文摘]

English. The effect of calcium nitrate on relative physiological parameters of muskmelon softness was studied.The regulation measures of prolong fruit shelf-life were explored to provide theoretical basis for calcium use to prolong the optimal edible phase and shelf-life,and to learn the mechanism of calcium delaying the process of ripening and senescence.Muskmelon discs taken at ripening stage were treated with different concentrations of calcium nitrate（1,3 and 5 mmoloL-1） and various time（4,8,12,16,20 and 24h） in order to investigate the fruit softness and the relative physiological parameters.The results showed that calcium nitrate treatment slowed apparently down the softness,elevated the flesh firmness,retarded the ethylene production and respiratory rate,and suppressed PG,PE and CMC-Na activities.However,different concentrations and time had various influences in the process of fruit softness.Compared with the control（6.09-6.81 kg・cm-2）,the firmness of calcium treatments was 0.22-1.24 kg・cm-2 higher.Moreover,compared with 1 and 3 mmol・L-1,5 mmol・L-1 treatment could more significantly inhibited the flesh respiratory,ethylene production and PG,PE and CMC-Na activities,the inhibition of flesh softness was apparently enhanced.Similiarly,the former was higher with 0.02-0.34 kg・cm-2 higher than the latter.Calcium nitrate treatment for 4h enhanced flesh firmness,reduced ethylene production and respiratory rate,and suppressed PG,PE,CMC-Na activities.After the discs were treated by calcium nitrate for 12h,the above relative softness parameters were inhibited in the lowest level among different treating time.Under 24h treatments,the ethylene production,PE and CMC-Na activities increased slightly,but there were significant differences of the above parameters with control.5 mmol・L-1 calcium nitrate and treating for 12h could delayed the process of the muskmelon softness.