| Cut rose is quite favored by people because of elegant form and gorgeous color which is called"queen of flower". However its life is short, quality of appreciation is easier to drop, symptoms including the flowers cannot blossom normally; petals become wilting and fall off precociously; browning on edges and short vase life, etc. As an advanced cooling technology, vacuum cooling can eliminate field heat efficiently, guarantee cut flower quality and extend its vase life. The article uses cut rose and cut gerbera as test pieces, applied the vacuum cooling and then refrigerated and observed. We want to study the effect of mass loss, membrane permeability, pH value and vase life of cut rose with different pressure reduction rates, to learn the effect of relitave water content, membrane permeability, enzyme activity and vase life and temperature of cut rose with different loadages, to discuss the temperature distribution and change rule of cut rose with different loadages, and finally compared the difference in temperature-detecting of cut gerbera during vacuum cooling by thermoelectric couple and thermal infrared imaging. Main research results are as follows:1. Treated the cut roses with the pressure reduction rates by 310.63mbar/min, 178.04mbar/min and 62.12mbar/min during the vacuum cooling process. Results showed that treatment of 310.63mbar/min has the worst effect because it causes the breakup of cell membrane and increases the senescence. Although the treatments of 178.04mbar/min and 62.12mbar/min have no significant effect in EL, MDA content, SOD activity and pH value, the time of treatments is 5.6 min and 16.0 min. Considering the time and efficiency, the treatment of 178.04mbar/min has the best effect.2. Treated the cut rose with the different loadage of 20, 50 and 120 pieces and the results show that compared with the bigger loadage, the smaller treatments can keep the higher RWC, SOD, POD and CAT activity, maintain lower EL and MDA content, which means the loadage have significant effect on the quality of cut rose during the vacuum cooling and the smaller the better.3. Detecting the temperature change with the different loadages during the vacuum cooling by thermoelectric couple. It is found that the temperature varies by different loadage treatments and different tissues under the same loadage which means local environment formed by different quantity and branches of flower have influence on temperature change. Using the ratio of initial and final temperature to measuring the cooling effect: for single branch: petal> blade> stalk; for branchy cut flowers: cooling effect of stalk, blade and petal in core branch are all better than any organization in peripheral branches no matter the treatment of 20, 50 or 120 branches; Cooling effect of petal is the best among all tissues of core branch, blade worse and stalk worst. Cooling effect of all tissues in peripheral branches shows no obivious regular under the different loadages.4. Detected the temperature distribution and change in different parts of cut gerbera by thermal infrared imaging and thermocouple, the result showed the temperature distribution is non-uniform. Ligule-shape petal has the fast average cooling rate while stem has slowest. Compared with method of thermal infrared imaging, the final temperature of different parts obtained with thermal images vary from 4.55 to 10.4℃,which means the temperature detecting by thermocouple is change by the fit method, fit position and vapor. |
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