Perennial plants maintain their life span through several growth seasons. Arabis alpina serves as model Brassicaceae species to study perennial traits. A. alpina lateral stems have a proximal vegetative zone with a dormant bud zone, and a distal senescing seed-producing inflorescence zone. We addressed the questions of how this zonation is distinguished at the anatomical level, whether it is related to nutrient storage, and which signals affect the zonation. We found that the vegetative zone ehxibits secondary growth, which we termed the perennial growth zone (PZ). High-molecular weight carbon compounds accumulate there in cambium and cambium derivatives. Neither vernalization nor flowering were requirements for secondary growth and sequestration of storage compounds. The inflorescence zone with only primary growth, termed annual growth zone (AZ), or roots exhibited different storage characteristics. Following cytokinin application, cambium activity was enhanced and secondary phloem parenchyma was formed in the PZ and also in the AZ. In transcriptome analysis cytokinin-related genes represented enriched gene ontology terms and were expressed at higher level in PZ than AZ. Thus, A. alpina uses primarily the vegetative PZ for nutrient storage, coupled to cytokinin-promoted secondary growth. This finding lays a foundation for future studies addressing signals for perennial growth.

中文翻译：

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细胞分裂素促进拟南芥多年生茎区的次级生长和养分存储

多年生植物在几个生长季节中都能维持其寿命。拟南芥作为模式十字花科物种研究多年生性状。A. alpina侧茎具有近端营养区和休眠芽区，而近端营养区带有休眠芽区，而远端种子产生花序区。我们解决了以下问题：如何在解剖学上区分该分区，是否与养分存储有关以及哪些信号会影响分区。我们发现植物生长带阻碍了次生生长，我们称其为多年生生长带（PZ）。高分子量的碳化合物在那里堆积在形成层和形成层中。春化和开花都不是二级生长和隔离存储化合物的要求。仅初生的花序区，称为年生区（AZ），或根表现出不同的存储特性。应用细胞分裂素后，形成层的活性增强，继发韧皮部实质在PZ和AZ中形成。在转录组分析中，与细胞分裂素相关的基因代表丰富的基因本体术语，并且在PZ中的表达水平高于AZ。因此，A。alpina主要使用营养性PZ进行营养物储存，并结合细胞分裂素促进的次级生长。这一发现为未来研究解决常年增长的信号奠定了基础。在转录组分析中，与细胞分裂素相关的基因代表丰富的基因本体术语，并且在PZ中的表达水平高于AZ。因此，A。alpina主要使用营养性PZ进行营养物储存，并结合细胞分裂素促进的次级生长。这一发现为未来研究解决常年增长的信号奠定了基础。在转录组分析中，与细胞分裂素相关的基因代表丰富的基因本体术语，并且在PZ中的表达水平高于AZ。因此，A。alpina主要使用营养性PZ进行营养物储存，并结合细胞分裂素促进的次级生长。这一发现为未来研究解决常年增长的信号奠定了基础。