Effects of potassium on fruit soluble sugar and citrate accumulations in Cara Cara navel orange (Citrus sinensis L. Osbeck)

摘要: Abstract Sugars and organic acid are key factors for sensory properties of fruit quality. Potassium (K) is an essential macroelement also known as quality element. This study aims to investigate how K affects improvement particularly sucrose, fructose, glucose citrate accumulations in Cara navel orange. fertilizer increased concentrations the ratios total soluble sugars citrate, more treatment 0.50 kg/plant fertilizer. These results showed that suitable amount could improve Further that, at early stage development, played important roles degrading sucrose due activities sucrose-degrading enzymes including invertase synthase-cleavage activity. Conversely, late re-synthesizing higher sucrose-synthesizing synthase-synthetic activity phosphate synthase. The above suggested upregulations enzyme caused by were conducive improving metabolism sink strength, then fructose fruit. citrate-synthesizing synthetase phosphoenolpyruvate carboxylase, but had no significant impacts on citrate-degrading enzyme, indicating least partially promoting its synthesis. finally improved sugar