Study On Respiration Intensity Of Different Parts Of Several Fruits And Wound Respiration

Based on technical parameter of respiration intensity of fruits measured by means of infrared CO₂ analyzer, this paper investigated the respiration volume of different parts of fruits, such as apple, pear, peach, nectarine, persimmon, grape, kiwifruit and Winter jujube. The effect of fruit falling from different height on the respiration process was also studied for apple, pear, peach and nectarine. The test results are showed as follows.The infrared CO₂ analyzer can be used to measure the respiration intensity of fruits. Tests showed that the remaining space in respiration room, the velocity of gas flow and temperature affected the respiratory intensity of tested fruits. This indicated that CO₂ analyzer was reliable for measuring fruit respiration intensity under different temperatures. The required period of time was short and the measured value was stable when the remaining space in respiration room in relation to the volume of the tested fruit was 2⁴:1 and the velocity of gas flow is 400 ml/min.By using the optimized technical parameters as stated in above, the respiration channel was studied for different fruits, such as apple, pear, peach, nectarine, persimmon, grape, kiwifruit and Winter jujube. The result showed that peel respiration in Starking Delicious and Fuji apple accounted for 87% of total respiratory volume, while, the peel respiration of Yali and Kuerle Fragrant pears accounted for 90% and 80%, respectively. For the 4 types of pome fruit, the proportion of stem respiration was almost the same as that of calyx respiration. The proportion of peel respiration of Beijing No.14 peach and in stone fruit, such as Yellow Nectarine, was about 96%, and that of stem respiration was about 4%. There were relatively large differences among the berry fruits. The proportion of peel respiration of Kyoho grape was 70% compared to 67% of kiwifruit and 30% of persimmon. For uncommon fruits such as Winter jujube, the peel respiration was 44%, and stem respiration accounted for 56%. The results showed that peel respiration in relation to total fruit respiration of pome fruit and nut fruit accounted for more than 80%, which indicated the peel was the main respiration channel. For the berry fruits, the proportion of peel respiration to stem respiration was approximately 7:3, while for jujube, the proportion was about 4:6. For persimmon, the main respiration channel was pedicel, and the respiration of pedicel accountedfor70% of total respiration volume of fruit.Experiments of free falling were carried out from different height (0.5 m—2.0 m) for apple, pear and peach. Tests showed that peach was sensitive to mechanical wounds. The Wound respiration of Beijing No.14 peach and Yellow Nectarine increased rapidly in 10 min. The peak respiration rate reached in 30 min. The respiration rate increase of Yali became evident after 30min and the peak respiration rate occurred after 3 hours. The respiration rate increase of Fuji apple became evident after 30min and the peak respiration rate occurred after 3⁵ hours. The higher of the falling height, the more the respiration rate increased and the earlier the peak respiration existed.