毛花猕猴桃‘赣猕6号’果实发育期间色素变化及呈色分析

Changes of pigment contents and flesh color generation analysis during fruit development of‘Ganmi 6'(Actinidia eriantha)

【目的】探讨毛花猕猴桃果实发育期间果肉色素的变化规律及呈色原因。【方法】以毛花猕猴桃‘赣猕6号’果实为试材,进行果肉色度、叶绿素、类胡萝卜素含量的测定及各指标间的相关性分析。【结果】整个果实发育阶段果肉色度稳固上升;叶绿素含量在盛花后95 d之前基本维持在60 mg·kg-1,盛花后110 d达到最小值(47.7 mg·kg-1),而在盛花后140 d快速上升至整个时期最大值(92.0 mg·kg-1),采收时下降到73.0 mg·kg-1;整个过程中叶绿素a含量所占比例显著高于叶绿素b;类胡萝卜素含量在盛花后110 d之前表现稳定,后期先上升再下降,于盛花后140 d达到最大值(26.3mg·kg-1),采收时下降至21.2 mg·kg-1;叶绿素和类胡萝卜素均与叶绿素a、叶绿素b、色度呈极显著相关,且2者之间亦呈极显著相关。【结论】整个果实发育阶段高含量的叶绿素是毛花猕猴桃果肉持续呈现绿色的原因。

[ Objective ]The flesh colors of Actinidia Lindl. have shown priorities for green, yellow and red, the present-color materials primarily associated with chlorophyll, carotenoids, anthocyanins and other pigments, which are the relative contents for determining the fruit＇ s color. As a unique berry resource in our country, Actinidia erientha Benth. is mainly distributed in Jiangxi, Zhejiang, Yunnan, Guizhou, Fujian and Hunan provinces, mostly in their wild state, which has rich antioxidants, and a high content of ascorbic acid and other nutrients, Its flowers and fruits have strong ornamental value, and in addition, the fruit is easy-peeling and tree resistance is strong. With all these advantages, A. eriantha has a broad prospect for development and utilization. At present, the flesh color of the kiwifruit has gotten more and more attention, but the color analysis research of the green-flesh kiwifruit during the whole development process has not yet been reported. In this study, we want to explore the changes of pigment contents during the fruit development of A, eriantha. [ Methods ]A. eriantha ＇ Ganmi 6＇ fruits were collected from the kiwifruit orchard of the Fengxin County Agricultural Bureau of Jiangxi Province. 15 kiwi fruits were randomly selected ev- ery 15 days beginning 20 days after full bloom to 170 days after full bloom until reaching their mature stage, which totaled 11 times. Five similar situations were selected as sampling trees, and 3 disabled fruits were also chosen. The collected samples were wrapped with a polyethylene closure pocket and stored in an ice box. Subsequently, the fruits were transported to the laboratory. The fruit flesh was cut up, then frozen using liquid nitrogen and stored at-80 ℃. Colorimeter （MINOLTA CR-400） was used to determine the h＊ values of the ＇Ganmi 6＇ fruit＇s flesh for each period. H＊ represents the hue angle. When h＊ = 0°- 90°, the colors changed from a purplish red （0°）, red, orange-red, orange yellow to yellow （90°） along with the increase of the hue angle. When h＊ = 90°- 180°, the colors changed from yellowish green, green to bluish green （180°） along with the increase of the hue angle. The method of chlorophyll and carotenoids extraction and determination were referenced from Li Hesheng. Each experiment was repeated 3 times. [ Results] The hue angle of the flesh in the ongoing process of the＇ Ganmi 6＇ fruit＇ s development rose stably. The rising range of each stage was small, the rates for every 30 d were 2.94%, 0.55%, 1.29%, 0.34% and 0.47%, which only obviously changed at 20-50 days after full bloom and 80-90 days after full bloom with 118.55% rising to 120.45% and 121.66% rising to 122.38% respectively. The chlorophyll a content reached a peak of 46.6 mg·kg^-1 at 95 days after full bloom, then fell to a low point of 31.9 mg·kg^-1 at 110 days after full bloom, which was the minimum result for all the periods. Later we saw an increase to the top, 62.9 mg·kg^-1 at 140 days after full bloom, at then it decreased to 47.6 mg·kg^-1 at 170 days after full bloom. The chlorophyll b content reached a peak of 25.8 mg·kg^-1 at 80 days after full bloom, then fell sharply to 15.8 mg·kg^-1 at 110 days after full bloom, After that, it rose to a max value of 29.1 mg·kg^-1. At finally, it was 25.4 mg·kg^-1 at picking time. The chlorophyll content was 47.7 mg·kg^-1 at 110 days after full bloom which was the minimum content during the entire development time. Following this, the chlorophyll content then rose to its maximum content of 92.0 mg·kg^-1 at 140 days after full bloom, and then down to 73.0 mg·kg^-1 at harvest time. And the consequences obtained from chlorophyll a had a greater impact than chlorophyll b. The carotenoids content remained stable until 110 days after full bloom, and then it showed an up-down trend, rising to the maximum （26.3 mg·kg^-1） at 140 days after full bloom, then reducing to 21.2 mg·kg^-1 at harvest time. The chlorophyll/carotenoid （ratio） in the process of the ＇ Ganmi 6＇ fruit development appeared to show a trend of down-up-down-up, with a generally downward trend. It had a maximum value （4.02） at 20 days after full bloom, then declined to a low point of 3.34 at 65 days after full bloom, and then after- wards increased to 4.02 at 80 days after full bloom, followed by a minimum value （3.09） at 110 days after full bloom, and then up to a value of 3.51 at 140 days after full bloom; in the last stage it remained unchanged with a value of 3.44 in the harvest period （170 days after full bloom）. Chlorophyll and carotenoid were significantly correlated with chlorophyll a, chlorophyll b and the hue angle, the two also had signifi- cant correlation with each other. [Conclusion] With the observation of the ＇Ganmi 6＇ pigment contents during fruit development, we found that the chlorophyll content was basically maintained at 60.0 mg·kg^-1 up to 95 days after full bloom, then it rose to a maximum content （92.0 mg·kg^-1） at 140 days after full bloom, and it always occupied a larger proportion in the total high level contents of the pigments. Although there was some degradation in the chlorophyll and carotenoid contents after 140 days following full bloom, the remaining pigments contents were still higher than the young fruit stage. This result was differ- ent from the other varieties of the kiwifruit. Correlation analysis showed that chlorophyll and carotenoid had a highly significant correlation with chlorophyll a, chlorophyll b and the hue angle, and also there was observed a highly significant correlation between the chlorophyll and carotenoid. It was the high expression level of chlorophyll which kept the flesh color green throughout the development of A. eriantha.