The development of woody plants is related to the continuity of the procambium and cambium. Whether such a continuity is present in plants with successive cambia, especially in those, where the first cambium is formed outside the primary vascular bundles, has not been analyzed so far. Therefore, we studied the development of vascular meristem in Celosia argentea, in which the first and successive cambial cylinders arise outside the primary bundles and, intriguingly, in the literature are interpreted as developmentally independent structures. Our results showed that in C. argentea, the outermost procambial cells maintain their meristematic characteristics during differentiation of vascular bundles and divide periclinally, forming the zone of procambium-derived cells outside the primary bundles. This zone comprises parenchyma cells bordering the bundles, and a continuous ring of the incipient cambial cells neighboring the primary cortex. Later in the development, the ability to preserve the outermost cells in the cambium undifferentiated is repeated during the formation of successive cylinders of cambia. Together, our results clearly point to the developmental continuity of the procambium and successive cambia in C. argentea, despite their seemingly spatial distinctiveness. We postulate that the mechanism demonstrated in C. argentea is universal and orchestrates the development of successive cambia in other plant species.

中文翻译：

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龙葵连续形成形成过程中原形成层和异常形成层的连续性

木本植物的发育与原形成层和形成层的连续性有关。到目前为止，尚未分析这种连续性是否存在于具有连续形成层的植物中，特别是在那些第一形成层形成于初级维管束之外的植物中。因此，我们研究了 Celosia argentea 维管分生组织的发育，其中第一个和连续的形成层圆柱出现在初级束之外，有趣的是，在文献中被解释为发育独立的结构。我们的结果表明，在 C. argentea 中，最外层的原形成细胞在维管束分化过程中保持其分生组织特征，并沿周分裂，在初级束外形成原形成细胞区。该区域包括与束接壤的薄壁组织细胞，以及与初级皮层相邻的初始形成层细胞的连续环。在发育的后期，在形成连续圆柱体的形成过程中重复保持未分化形成层中最外层细胞的能力。总之，我们的结果清楚地指出了 C. argentea 中原形成层和连续 cambia 的发展连续性，尽管它们看似空间独特。我们假设在 C. argentea 中展示的机制是普遍的，并且在其他植物物种中协调了连续 cambia 的发展。在形成连续圆柱体形成过程中，形成层中最外层细胞保持未分化的能力重复出现。总之，我们的结果清楚地指出了 C. argentea 中原形成层和连续 cambia 的发展连续性，尽管它们看似空间独特。我们假设在 C. argentea 中展示的机制是普遍的，并且协调了其他植物物种中连续 cambia 的发展。在形成连续圆柱体形成过程中，形成层中最外层细胞保持未分化的能力重复出现。总之，我们的结果清楚地指出了 C. argentea 中原形成层和连续 cambia 的发展连续性，尽管它们看似空间独特。我们假设在 C. argentea 中展示的机制是普遍的，并且在其他植物物种中协调了连续 cambia 的发展。