On the relationship between phyllotaxy and vasculature: a synthesis

Kirchoff, Bruce K.

doi:10.1111/j.1095-8339.1984.tb00999.x

Cited by 24 publications

(25 citation statements)

References 39 publications

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“…In most species, the spatial organization of the vasculature in the shoot apex is strictly correlated with phyllotactic patterns (Kirchoff, 1984), and expression analysis of the early procambial marker HOMEOBOX GENE 8 in Arabidopsis thaliana has supported these findings (Kang et al, 2003). Hence, vascular development and organ formation are closely correlated.…”

Section: Exploring the Role Of The Developing Midvein In Phyllotaxismentioning

confidence: 97%

Phyllotaxis involves auxin drainage through leaf primordia

et al. 2015

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The spatial arrangement of leaves and flowers around the stem, known as phyllotaxis, is controlled by an auxin-dependent reiterative mechanism that leads to regular spacing of the organs and thereby to remarkably precise phyllotactic patterns. The mechanism is based on the active cellular transport of the phytohormone auxin by cellular influx and efflux carriers, such as AUX1 and PIN1. Their important role in phyllotaxis is evident from mutant phenotypes, but their exact roles in space and time are difficult to address due to the strong pleiotropic phenotypes of most mutants in phyllotaxis. Models of phyllotaxis invoke the accumulation of auxin at leaf initials and removal of auxin through their developing vascular strand, the midvein. We have developed a precise microsurgical tool to ablate the midvein at high spatial and temporal resolution in order to test its function in leaf formation and phyllotaxis. Using amplified femtosecond laser pulses, we ablated the internal tissues in young leaf primordia of tomato (Solanum lycopersicum) without damaging the overlying L 1 and L 2 layers. Our results show that ablation of the future midvein leads to a transient accumulation of auxin in the primordia and to an increase in their width. Phyllotaxis was transiently affected after midvein ablations, but readjusted after two plastochrons. These results indicate that the developing midvein is involved in the basipetal transport of auxin through young primordia, which contributes to phyllotactic spacing and stability.

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Section: Exploring the Role Of The Developing Midvein In Phyllotaxismentioning

confidence: 97%

Phyllotaxis involves auxin drainage through leaf primordia

et al. 2015

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“…We propose that the influence of preexisting leaves on phyllotaxis is mediated by their vasculature, possibly by defining the routes of auxin transport to the meristem. Such a relationship between vasculature and phyllotaxis has been suggested on the basis of histologic analysis (Larson, 1975;Kirchoff, 1984). Auxin transport is associated with the vasculature; conversely, auxin induces vascular differentiation (Sachs, 1991;Davies, 1995).…”

Section: Leaf Primordiamentioning

confidence: 99%

Auxin Regulates the Initiation and Radial Position of Plant Lateral Organs

Reinhardt¹,

Mandel²,

Kuhlemeier³

2000

The Plant Cell

168

251

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Leaves originate from the shoot apical meristem, a small mound of undifferentiated tissue at the tip of the stem. Leaf formation begins with the selection of a group of founder cells in the so-called peripheral zone at the flank of the meristem, followed by the initiation of local growth and finally morphogenesis of the resulting bulge into a differentiated leaf. Whereas the mechanisms controlling the switch between meristem propagation and leaf initiation are being identified by genetic and molecular analyses, the radial positioning of leaves, known as phyllotaxis, remains poorly understood. Hormones, especially auxin and gibberellin, are known to influence phyllotaxis, but their specific role in the determination of organ position is not clear. We show that inhibition of polar auxin transport blocks leaf formation at the vegetative tomato meristem, resulting in pinlike naked stems with an intact meristem at the tip. Microapplication of the natural auxin indole-3-acetic acid (IAA) to the apex of such pins restores leaf formation. Similarly, exogenous IAA induces flower formation on Arabidopsis pin-formed1-1 inflorescence apices, which are blocked in flower formation because of a mutation in a putative auxin transport protein. Our results show that auxin is required for and sufficient to induce organogenesis both in the vegetative tomato meristem and in the Arabidopsis inflorescence meristem. In this study, organogenesis always strictly coincided with the site of IAA application in the radial dimension, whereas in the apical-basal dimension, organ formation always occurred at a fixed distance from the summit of the meristem. We propose that auxin determines the radial position and the size of lateral organs but not the apical-basal position or the identity of the induced structures.

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“…Barlow 1979;Pate & Fartington 1981 ;Shea & Watson 1989). Thus, phyllotaxy controls sectorial patterns of assimilate movement (Larson 1977;Kirchoff 1984;Oparka & Davies 1985;Watson 1986) and therefore influences which plant parts will be physiologically integrated, i.e. Thus, phyllotaxy controls sectorial patterns of assimilate movement (Larson 1977;Kirchoff 1984;Oparka & Davies 1985;Watson 1986) and therefore influences which plant parts will be physiologically integrated, i.e.…”

Section: Introductionmentioning

confidence: 99%