Vein Pattern Development in Adult Leaves of Arabidopsis thaliana
Vein Pattern Development in Adult Leaves of Arabidopsis thaliana
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DOI：
10.1086/382794
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发表时间：
2004-03
影响因子：
2.3
通讯作者：
Julie Kang;N. Dengler
中科院分区：
文献类型：
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作者：
Julie Kang;N. Dengler
高等植物叶子中的静脉图案发育需要从地面分生组织前体重新形成具有分级静脉尺寸类别和规则间距的连续系统。在本研究中，我们使用原形成层身份的分子标记 AtHB-8::GUS 来研究拟南芥成年莲座叶中静脉图案形成的原形成层阶段，并将 AtHB-8 标记的静脉图案的形成与木质部分化表达的静脉图案的形成进行比较。虽然经过充分研究的拟南芥幼叶具有相对简单的枝状静脉图案，同时出现环状次脉，但成年叶具有复杂的半弯状静脉图案，并且大多数直次脉逐渐发育。晚形成的次脉要么出现在叶子的基部，要么插入在早形成的次脉之间。较小的“连接器”静脉在发育过程中变得增强，形成半蔓状次静脉模式的亚末端环。高阶静脉，特别是自由末端的小脉，在叶子扩张过程中形成，保持稳定的静脉密度。成年叶脉图案的这些独特特征与边缘锯齿的存在和叶子扩张的长期时间密切相关。在早期叶发育中，AtHB-8::GUS 表达先于假定原形成链中原形成层细胞的任何标志性解剖特征，定义了“前原形成层”阶段。相比之下，在高级静脉的后期形成过程中没有检测到 AtHB-8::GUS 表达，表明功能冗余机制指导叶维管模式的发展。
Vein pattern development in the leaves of higher plants requires that a continuous system with hierarchical vein size classes and regular spacing be formed de novo from ground meristem precursors. In this study, we use a molecular marker of procambium identity, AtHB‐8::GUS, to investigate the procambial stage of vein pattern formation in adult rosette leaves of Arabidopsis thaliana and to compare the elaboration of AtHB‐8‐marked vein pattern with that expressed by xylem differentiation. While the well‐studied juvenile leaves of Arabidopsis have a relatively simple brochidodromous vein pattern with the simultaneous appearance of the looped secondary veins, adult leaves have a complex semicraspedodromous vein pattern, and a majority of the straight secondary veins develop progressively. Late‐formed secondary veins either arise in the basal portions of the leaf or are intercalated between earlier‐formed secondary veins. Smaller “connector” veins become enhanced during development to form the subterminal loops of the semicraspedodromous secondary vein pattern. Higher‐order veins, especially freely ending veinlets, are formed throughout leaf expansion, maintaining a stable vein density. These unique features of adult leaf vein pattern are strongly correlated with the presence of marginal serrations and a protracted period of leaf expansion. In early leaf development, AtHB‐8::GUS expression precedes any of the hallmark anatomical features of procambial cells in presumptive procambial strands, defining a “preprocambial” stage. In contrast, AtHB‐8::GUS expression was not detected during the late formation of higher‐order veins, indicating that functionally redundant mechanisms guide the development of leaf vascular pattern.