光照强度对厚皮甜瓜糖分积累与蔗糖代谢相关酶的影响

Effects of light intensity on sugar accumulation and sucrose-metabolizing enzymes in muskmelon

【目的】研究不同光照强度对厚皮甜瓜中3种糖分积累与4种蔗糖代谢相关酶活性的影响,以期找到适合秋冬茬甜瓜生长的光照强度。【方法】以＂一品天下108＂厚皮甜瓜品种为试材,在温度相同的日光温室隔间中,分别设置自然光照、自然光照＋补光50μmol/（m2.s）和自然光照＋补光100μmol/（m2.s）3个处理,分别于花后7,14,21,28,35,42 d采摘甜瓜果实,研究不同光照强度对甜瓜果实磷酸蔗糖合成酶（SPS）、蔗糖合成酶（SS）、中性转化酶（NI）、酸性转化酶（AI）活性及蔗糖、果糖、可溶性糖积累的影响。【结果】光照越强的处理,厚皮甜瓜果实中果糖、可溶性糖含量和2个转化酶活性越高;在花后7~21 d,光照越强的处理,厚皮甜瓜果实中蔗糖含量越低,但在花后28~42 d,光照最强的处理,果实中蔗糖含量却最高;SPS活性在厚皮甜瓜果实发育过程中呈波动变化,光照最强处理的果实中SPS活性随果实的成熟总体呈升高趋势;自然光照处理中,SS活性在果实发育过程中呈波动变化,2个补光处理果实中的SS活性变化趋势较一致,即在花后7~21 d活性较低,花后28~42 d活性明显升高。【结论】补光程度达到某一阈值后,才会对甜瓜果实糖分积累和蔗糖酶活性的变化有较大影响。就本试验而言,冬季补光50μmol/（m2.s）的效果不明显,补光100μmol/（m2.s）即可获得较为明显的效果。

【Objective】 This experiment was carried out to elucidate the effects of different light intensities on sugar accumulation and sucrose-metabolizing enzymes in muskmelon.【Method】 With Yipintianxia 108 as the experimental material,the changes of sugar accumulation and activities of enzymes related to sucrose metabolism in the development of muskmelon fruits under three different light conditions,the natural light,natural light＋50 μmol/（m2·s） and natural light＋100 μmol/（m2·s） in a greenhouse with the same temperature were studied.【Result】 The results show that the stronger the light is,the higher the fructose and soluble sugar content in the fruits are,while the activity of zymose also increases with the increase in light intensity;During 7-21 d after pollination,the stronger the light is,the higher the sucrose content in the fruits are;During 28-42 d after pollination,the sucrose content in the fruits is the highest which are cultivated in the strongest light treatment;Sucrose phosphate synthase activities fluctuate in the whole phase,and in the strongest light treatment,the sucrose phosphate synthase activities have an upward trend as the fruits grow;In the natural light treatment,sucrose synthase activities in the fruits fluctuate as the fruits grow,while in those two light strengthened treatments,the sucrose synthase activities are low in 7-21 d after pollination,and then increase significantly during 28-42 d after pollination.【Conclusion】 When the light intensity reaches a certain value,it exerts great impact on the sugar accumulation and sucrose-metabolizing enzymes in muskmelon.In this experiment,natural light＋100 μmol/（m2·s） has an obvious effect while the effect of natural light＋50 μmol/（m2·s） is not significant.