Foliar Venation in Angiosperms from an Ontogenetic Standpoint

Foster, Adriance S.

doi:10.2307/2438624

Cited by 56 publications

(26 citation statements)

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“…Veins transport water and nutrients, and are source of signals that act locally, to assign identity to surrounding cells, and systemically, to coordinate initiation of new shoot organs with that of new roots (Berleth and Sachs, 2001). Sites of vein formation are foreshadowed by appearance of files of elongated procambial cells, which in leaf development seem to emerge de novo from within a homogeneous population of isodiametric ground cells (Louis, 1935;Esau, 1943;Foster, 1952).…”

Section: Introductionmentioning

confidence: 99%

Simultaneous activation of SHR and ATHB8 expression defines switch to preprocambial cell state in Arabidopsis leaf development

Gardiner

Donner

Scarpella

2010

Developmental Dynamics

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The processes underlying the formation of leaf vascular networks have long captured the attention of developmental biologists, especially because files of elongated vascular-precursor procambial cells seem to differentiate from apparently equivalent, isodiametric ground cells. In Arabidopsis leaves, ground cells that have been specified to vascular fate engage expression of ARABIDOPSIS THALIANA HOMEOBOX8 (ATHB8). While definition of the transcriptional state of ATHB8-expressing ground cells would be particularly informative, no other genes have been identified whose expression is initiated at this stage. Here we show that expression of SHORT-ROOT (SHR) is activated simultaneously with that of ATHB8 in leaf development. Congruence between SHR and ATHB8 expression domains persists under conditions of manipulated vein patterning, suggesting that inception of expression of SHR and ATHB8 identifies transition to a preprocambial cell state that presages vein formation. Our observations further characterize the molecular identity of cells at anatomically inconspicuous stages of leaf vein development. Developmental Dynamics 240:261-270,

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Section: Introductionmentioning

confidence: 99%

Simultaneous activation of SHR and ATHB8 expression defines switch to preprocambial cell state in Arabidopsis leaf development

Gardiner

Donner

Scarpella

2010

Developmental Dynamics

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“…From a developmental standpoint, the process is particularly fascinating because it seems to be organized de novo in each leaf primordium. At early stages of leaf ontogeny, in fact, the cells located beneath the epidermis appear as a morphologically homogeneous population of tightly connected, polygonal, isodia-metric cells ('ground cells') (Smith, 1934;Foster, 1936Foster, , 1952; during leaf development, complementary, anatomically inconspicuous subsets of ground cells will differentiate to generate procambial strands and the photosynthetic tissue of the leaf, the mesophyll.…”

Section: Introductionmentioning

confidence: 99%

Expression of DOF genes identifies early stages of vascular development in Arabidopsis leaves

Gardiner

Sherr²,

Scarpella

2010

Int. J. Dev. Biol.

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The sequence of events underlying the formation of vascular networks in the leaf has long fascinated developmental biologists. In Arabidopsis leaves, vascular-precursor procambial cells derive from the elongation of morphologically inconspicuous ground cells that selectively activate expression of the HD-ZIP III gene ATHB8. Inception of ATHB8 expression operationally defines acquisition of a typically irreversible preprocambial cell state that preludes to vein formation. A view of the constellation of genes whose expression is activated at preprocambial stages would therefore be particularly desirable; however, very few preprocambial gene expression profiles have been identified. Here, we show that expression of three genes encoding members of the DOF family of plant-specific transcription factors is activated at stages overlapping onset of ATHB8 expression. Expression of DOF genes is initiated in wide domains that become confined to sites of vein development. Congruence between DOF expression fields and zones of vein formation persists upon experimental manipulation of leaf vascular patterning, suggesting that DOF expression identifies consistently recurring steps in vein ontogeny. Our results contribute to defining preprocambial cell identity at the molecular level.

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“…El patrón de venación se estableció temprano en el desarrollo de la hoja de las cuatro especies estudiadas, originándose en primer lugar la(s) vena(s) primaria(s) y en segundo lugar, en un sentido acrópeto, a lo largo de la(s) vena(s) primaria(s) las venas secundarias. El desarrollo de las venas en estas Senecioneae tuvo un arreglo jerárquico; es decir, los cordones procambiales de las venas primarias se desarrollan antes que en las venas secundarias y así sucesivamente, concordando con lo registrado por varios autores (Foster, 1952;Merrill, 1979;Dengler y Kang, 2001). Además, la formación de las venas de orden superior se produjo más tarde, durante la expansión de la hoja en regiones preformadas.…”

Section: Discussionunclassified

“…Estos patrones de venación se establecieron cuando las hojas tenían longitudes de 2-13 mm (etapa a) y alcanzaron su estado maduro, con longitudes de 22-31 mm (etapa c). El establecimiento temprano del patrón de venación también se ha registrado en otras familias (Foster, 1952;Slade, 1957;Merrill, 1979). Venas de órdenes superiores.…”

Section: Discussionunclassified

“…En varias familias de dicotiledóneas se ha estudiado la ontogenia tanto de hojas simples como compuestas para entender la formación del patrón de venación o dilucidar el desarrollo de la venación reticulada y el origen de las vénulas (Johnson, 1943;Foster, 1952;Slade, 1957Slade, , 1959Pray, 1963;Lersten, 1965;Herbst, 1972;Merril, 1979). En estos estudios se registra que el grado de división de la lámina, la forma de la hoja y el patrón de venación se evidencían desde tempranas etapas del desarrollo, cuando el primordio cuenta con cerca de 200 μm de longitud.…”

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Desarrollo del patrón de venación en cuatro especies de la tribu Senecioneae (Asteraceae)

2014

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Resumen: Para conocer los cambios que ocurren durante el desarrollo del patrón de venación e identifi car si la forma de la lámina determina el patrón de venación en miembros de la tribu Senecioneae (Asteraceae), en este trabajo se describió y comparó el desarrollo del patrón de venación durante la expansión de la hoja de Packera sanguisorbae, Psacalium peltatum, Roldana angulifolia y R. lineolata, cuyas morfologías son contrastantes (formas redondas vs. elípticas, y láminas no divididas vs. fuertemente lobuladas). Se recolectaron desde ápices vegetativos hasta hojas completamente desarrolladas y se aclararon con una mezcla de fucsina básica-NaOH para la observación de la venación. Los resultados mostraron que el tipo de margen, la disección de la lámina y el patrón de venación (venas primarias y secundarias), se establecen en estadios tempranos del desarrollo, cuando la lámina cuenta con alrededor del 3% de su longitud; la forma de la lámina se establece en etapas posteriores. El desarrollo de las venas tuvo un arreglo jerárquico como en otros taxa. Sin embargo, los órdenes de venación difi eren entre lóbulos y dientes. Los lóbulos son irrigados sólo por venas de primer y segundo orden, mientras que en los dientes pueden llegar venas hasta de séptimo orden. Con la forma de la hoja se pudo predecir el patrón de venación, excepto en aquellas de forma elíptica. En las especies de Packera, el patrón de venación semicraspedódromo festoneado se mantiene, sin importar si la lámina está o no dividida. Se concluye que el establecimiento temprano del patrón de venación y la forma de la hoja son caracteres de potencial importancia taxonómica en la tribu Senecioneae. Palabras clave: dientes, expansión de la hoja, lóbulos, órdenes de venación, Packera, Psacalium, Roldana. Abstract:The venation pattern development was described and evaluated during leaf expansion in Packera sanguisorbae, Psacalium peltatum, Roldana angulifolia, and R. lineolata of the Senecioneae tribe (Asteraceae) with contrasting morphologies (round versus elliptical shape, and entire versus deeply lobed lamina). The aims of this study were to identify the changes that occur during the venation pattern development and to determine if lamina shape correlates with the venation pattern. Leaves of different ages from meristematic apexes to fully developed leaves were collected and cleared with a basic fuchsin-NaOH mixture. The results showed that type of margin, dissection of lamina, and the venation pattern (primary and secondary veins) are fi xed since early stages of the development, when the lamina counts on 3% of its length. However, lamina shape is acquired later in development. Veins development followed a hierarchical pattern as described for other taxa. However, venation orders varied between lobes and teeth. Lobes are irrigated by primary and secondary veins, while up to 7 th orden veins are found in the teeth. Leaf shape may predict the venation pattern except when the leaf has an elliptic shape. In Packera the festooned semicraspedodromous venation...

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Foliar Venation in Angiosperms from an Ontogenetic Standpoint

Cited by 56 publications

References 0 publications

Simultaneous activation of SHR and ATHB8 expression defines switch to preprocambial cell state in Arabidopsis leaf development

Simultaneous activation of SHR and ATHB8 expression defines switch to preprocambial cell state in Arabidopsis leaf development

Expression of DOF genes identifies early stages of vascular development in Arabidopsis leaves

Desarrollo del patrón de venación en cuatro especies de la tribu Senecioneae (Asteraceae)

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