Physiological And Biochemical Study Of Loquat Fruit (Eriobotrya Japonica Lindl.) In North-cultivated-marginal Area During Growth And Postharvest

The south area of Qinling Mountains is the north margin of natural distribution of the loquat in China. In this experiment, loquat fruit(Eriobotrya japonica Lindl.) that grew in Ankang Shaanxi were used as experiment materials, the physiological changes of loquat fruit in growth course of fruitage and the effects of different concentrations exgenous hormones (such as GA₃ and Put) on physiological and biochemical of cold storage loquat fruit after harvest were studied. Features of quality and physiological changes in postharvest loquat fruit has been discussed, to provide theoretical foundation for culture management and fresh preservation of loquat fruit under North-cultivated-marginal area growing conditions. Results were as followings:1.The growth curves of loquat fruit showed an"S"shape. Fresh weight grew slowly at prophase, and then their growth was accelerated at the early ripening time.2.The changes of fruit inclusion content during loquat fruit growth and development were as follows: (1) the content of soluble sugar changed unremarkably in the early stage of fruit development, then accumulated rapidly at the early maturation time. (2) The content of titratable acid was low at the beginning of fruit set. With the development of fruit, titratable acid content increased, and it decreased rapidly near the fruit maturity. (3) The content of vitamin C was low in the early stage of fruit development, then increased with the development of fruit during growth, and then decreased lightly.3.No respiratory climacterric occurred during fruit growth and storage, so loquat fruit belonged to non-climacteric fruit.4.GA₃ treatments inhibited the increase of clod storage loquat fruit firmness and respiratory rate, delayed the increase of lignification related enzymes activites, remained the activites of antioxidant enzymes in a high level, lowered the incidence of fruit decay , thereby keeping fruit quality and prolonging storage life. Comparatively, lower concentration of GA₃ (10μmol/L) effectively delayed the decrease of soluble sugar and titratable acid contents, inhibited the increase of relative electric conductivity, at the end of the storage(after stored 49 days), the healthy fruit ratio of loquat was 97.5%, however the control group was only 61.5%.5.Put treatments promoted the increase of the firmness, relative electric conductivity and activities of lignification related enzymes, accelerated the decrease of the titratable acid content, which was resulted in chilling injury aggravated and reduce of fruit quality. However Put treatments could delay the rebound increase of the respiratory rate and significantly improve the activities of antioxidant enzymes to reduce decay symptoms of the fruits, by which the healthy fruit ratio was still maintained about 70% that higher than that of the control.