We develop a model based on the biophysical representation of water and sugar flows between the pedicel, fruit xylem and phloem, and the fruit apoplast and symplast in order to identify diurnal patterns of transport in the pedicel–fruit system of peach. The model predicts that during the night water is mainly imported to the fruit through the xylem, and that fruit phloem–xylem transfer of water allows sugar concentrations in the phloem to be higher in the fruit than in the pedicel. This results in relatively high sugar transport to the fruit apoplast, leading to relatively high sugar uptake by the fruit symplast despite low sugar concentrations in the pedicel. At midday, the model predicts a xylem backflow of water driven by a lower pressure potential in the xylem than in the fruit apoplast. In addition, fruit xylem-to-phloem transfer of water decreases the fruit phloem sugar concentration, resulting in moderate sugar uptake by the fruit symplast, despite the high sugar concentration in the pedicel. Globally, the predicted fruit xylem–phloem water transfers buffer the sugar concentrations in the fruit phloem and apoplast, leading to a diurnally regulated uptake of sugar. A possible fruit xylem-to-apoplast recirculation of water through the fruit phloem reduces water lost by xylem backflow at midday.

中文翻译：

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桃花梗果实系统的模型辅助分析表明，调节糖的摄取和节水策略。

我们基于花梗，果实木质部和韧皮部，韧皮部与果实的质外体和共生质之间的水和糖流动的生物物理表示，开发了一个模型，以便确定桃的花梗－果实系统中的昼夜运输模式。该模型预测，在夜间，水主要通过木质部进入水果，并且韧皮部-木质部中水的转移使韧皮部中的糖浓度高于花梗中的糖浓度。这导致相对较高的糖向水果质外体的运输，尽管花梗中糖的浓度较低，但导致水果共生体的糖摄入量相对较高。该模型预测，在午间时，木质部中的压力势可能低于果外质体中的木质部回流。此外，果实木质部到韧皮部的水转移降低了果实韧皮部的糖浓度，尽管花梗中糖浓度很高，但果实的共生体吸收了适量的糖。在全球范围内，预计的果实木质部-韧皮部水转移缓冲了果实韧皮部和质外体中的糖浓度，从而导致了糖的昼夜调节摄取。通过果实韧皮部的可能的果实木质部到质外体的再循环减少了中午木质部回流造成的水分流失。