The present review highlights both the fundamental questions of calcium localization, compartmentation, and its participation in symbiosome signaling cascades during nodule formation and functioning. Apparently, the main link of such signaling is the calmodulin…calcium- and calmodulin-dependent protein kinases…CYCLOPS…NIN…target genes cascade. The minimum threshold level of calcium as a signaling agent in the presence of intracellular reserves determines the possibility of oligotrophy and ultraoligotrophy in relation to this element. During the functioning of root nodules, the Ca²⁺-ATPases activity maintains homeostasis of low calcium concentrations in the cytosol of nodule parenchyma cells. Disturbation of this homeostasis can trigger the root nodule senescence. The same reasons determine the increase in the effectiveness of symbiosis with the help of seed priming with sources of calcium. Examples of calcium response polymorphism in components of nitrogen fixing simbiosis important in practical terms are shown.

本综述强调了钙定位、区室化及其在结节形成和功能过程中参与共生体信号级联的基本问题。显然，这种信号传导的主要环节是钙调蛋白…钙和钙调蛋白依赖性蛋白激酶…CYCLOPS…NIN…靶基因级联。在存在细胞内储备的情况下，钙作为信号剂的最低阈值水平决定了与该元素相关的寡营养和超寡营养的可能性。在根瘤的功能过程中，Ca ²⁺ -ATP酶活性维持根瘤薄壁细胞细胞质中低钙浓度的稳态。这种稳态的紊乱会引发根瘤衰老。同样的原因决定了在钙源种子引发的帮助下共生有效性的增加。显示了在实际应用中重要的固氮共生组分中的钙响应多态性的例子。