Abstract It remains true that through its signaling mechanisms, Ca2+ also has specific, direct effects on plant metabolic activities, which are poorly understood due to the currently trendy pursuit of Ca2+ signaling studies. This paucity triggered us to examine the virtues of calcium nutrition by investigating carbohydrate metabolism using combinations of physiological and microscopy techniques in Ca2+ sufficient and Ca2+ starved grapevines (Vitis vinifera L.). Net photosynthesis was severely down-regulated in Ca2+ deficient vines, which paralleled with altered chloroplast ultrastructure and reduced chlorophyll concentration. Interestingly, the activities of Rubisco, sucrose phosphate synthase (SPS), sucrose synthase (SS), and fructose-1, 6-bisphosphatase (FBPase) were elevated in Ca2+ deficient vines, while ADP-glucose pyrophosphorylase (AGPase) and phosphoribulose kinase (PRK) activities were reduced. Since plants evolved adaptive mechanisms to cope up with lack or excess of nutrients, these metabolic changes in Ca2+ deficient and sufficient grapevines could be interpreted as acclimation reactions to establish optimal homeostasis. However, given the controversial nature of calcium’s multifunctionality, we need concrete evidence for this radical new paradigm.

中文翻译：

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葡萄中酶活性的差异调节和钙营养的生理解剖学方面

摘要 确实，Ca2+ 通过其信号传导机制也对植物代谢活动具有特定的、直接的影响，由于当前对 Ca2+ 信号传导研究的流行追求，人们对此知之甚少。这种缺乏促使我们通过在 Ca2+ 充足和 Ca2+ 饥饿的葡萄藤 (Vitis vinifera L.) 中结合使用生理学和显微镜技术研究碳水化合物代谢来研究钙营养的优点。在 Ca2+ 缺乏的葡萄藤中，净光合作用严重下调，这与叶绿体超微结构的改变和叶绿素浓度的降低并行。有趣的是，在 Ca2+ 缺乏的葡萄树中，Rubisco、蔗糖磷酸合酶 (SPS)、蔗糖合酶 (SS) 和果糖-1, 6-双磷酸酶 (FBPase) 的活性升高，而 ADP-葡萄糖焦磷酸化酶 (AGPase) 和磷酸核酮糖激酶 (PRK) 活性降低。由于植物进化出适应机制来应对营养缺乏或过剩，Ca2+ 缺乏和充足的葡萄藤中的这些代谢变化可以解释为适应反应，以建立最佳稳态。然而，鉴于钙的多功能性存在争议，我们需要为这种激进的新范式提供具体的证据。