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猕猴桃果实发育过程中淀粉积累差异及其糖代谢特性

来源：花匠小妙招时间：2025-04-20 08:28

摘要： 【目的】探讨高、低淀粉积累型猕猴桃果实发育过程中淀粉积累差异、糖代谢特性及与相关酶活性的关系，为提高猕猴桃果实糖含量和风味等关键品质提供理论依据。【方法】以高淀粉积累型品种‘红阳’和低淀粉积累型品种‘华特’为试材，测定果实发育过程中的相对生长速率、碳水化合物（淀粉、葡萄糖、果糖和蔗糖）含量、干物质含量以及碳水化合物代谢相关酶活性的变化。【结果】果实碳水化合物含量与果实生长速率呈负相关，其含量随淀粉积累而不断增加；淀粉含量与果糖、葡萄糖、蔗糖等可溶性糖含量及干物质含量均呈正相关，当达峰值时，其在‘华特’和‘红阳’果实碳水化合物含量中所占比例分别为87.1%和84.1%。‘红阳’果实淀粉积累增速快、峰值高、时间长，其淀粉积累平均速率为0.685 mg•g-1FW•d-1，淀粉积累峰值为70.78 mg•g-1FW，分别是‘华特’的1.34倍和1.69倍，且其淀粉积累时间比‘华特’长21 d。‘华特’果实淀粉在采前已急剧下降，至采收时几乎都转化为可溶性糖；而‘红阳’果实淀粉含量仍直线增长，并在采前维持在一个较高水平。‘华特’果实的中性转化酶（NI）和酸性转化酶（AI）活性始终显著高于‘红阳’，而后者的蔗糖磷酸合成酶（SPS）和腺苷二磷酸葡萄糖焦磷酸化酶（AGPase）活性一直明显强于前者。‘红阳’和‘华特’的果实淀粉含量与AGPase和SPS活性的相关性最强，而与NI和AI活性呈较强负相关。NI活性与AI活性呈显著正相关，而与AGPase、SPS、蔗糖合成酶（SS）、果糖激酶（FK）、葡萄糖激酶（GK）、尿苷二磷酸葡萄糖焦磷酸化酶（UGPase）等酶活性均呈负相关；‘红阳’果实中的AGPase活性与SPS、SS、FK、GK、UGPase等酶活性均呈显著正相关。【结论】猕猴桃果实碳水化合物积累以淀粉为主，AGPase是影响淀粉积累的关键酶，NI、AI和SPS活性的差异可能是造成果实淀粉积累高低、干物质多少、可溶性糖组分及含量不同的重要原因。

关键词: 猕猴桃 , 果实发育 , 淀粉 , 糖代谢

Abstract: 【Objective】The aim of this work is to study difference in starch accumulation between high- and low-starch- accumulating cultivars and characterization of sugar metabolism during fruit development, and to identify the related enzymes activities in order to provide a theoretical guidance for increasing fruit sugar content and improving flavour and quality of fruit.【Method】High-starch-accumulating variety ‘Hongyang’ and low-starch-accumulating variety ‘White’ were used to measure the changes in fruit relative growth rate (RGR), carbohydrate content (starch, glucose, fructose and sucrose), dry matter and enzyme activity in relation to carbohydrate metabolism throughout the growing season.【Result】The carbohydrate concentration was negatively correlated with fruit relative growth rate, and constantly increased with starch accumulation. The starch content was positively correlated with the soluble sugar contents (glucose, fructose and sucrose) and dry matter, and the ratios of maximum starch content to carbohydrates in ‘White’ and ‘Hongyang’ fruit were 87.1% and 84.1%, respectively. The higher rate of starch accumulation, which was also maintained for a longer period of time, was found in ‘Hongyang’, and the starch peak was much higher in ‘Hongyang’ than in ‘White’. The rate of starch accumulation and the maximum starch content in ‘Hongyang’ were 0.685 mg•g-1FW•d-1 and 70.78 mg•g-1FW, and they were 1.34 and 1.69 fold higher than those in ‘White’, respectively. The period of starch accumulation of ‘Hongyang’ was 21 days longer than that of ‘White’. When starch content in ‘White’ fruit rapidly dropped, starch accumulation of ‘Hongyang’ fruit linearly increased. As a consequence, the higher level of starch concentration in ‘Hongyang’ fruit maintained until harvest, while almost all starch in ‘White’ had been converted into soluble sugars prior to harvest. Neutral invertase (NI) and acid invertase (AI) activities were consistently much higher in ‘white’ than in ‘Hongyang’. In contrast, ADP-glucose pyrophosphorylase (AGPase) and sucrose phosphate synthase (SPS) activity was always stronger in ‘Hongyang’ than in ‘White’. Fruit starch content was positively and significantly correlated with AGPase and SPS activities, but was negatively and strongly correlated with NI and AI activities. NI activity was positively and significantly correlated with NI activity, while was negatively correlated with the activities of AGPase, SPS, sucrose synthase (SS), fructokinase (FK), glucokinase (GK) and UDP-glucose pyrophosphorylase (UGPase). AGPase activity in ‘Hongyang’ had positive and significant correlation with the activities of SPS, SS, FK, GK and UGPase.【Conclusion】Kiwi fruit accumulated carbohydrate predominantly as starch. AGPase was a determinant of high starch concentration in fruit, in addition to this, the variation of NI, AI and SPS activity may be the causes of high or low contents of starch, dry matter and soluble sugars in fruit.

Key words: kiwi fruit , fruit development , starch , sugar metabolism