Relation between Phyllotaxis and Primary Vascular Organization in Linum

Girolami, Guido

doi:10.2307/2438450

Cited by 10 publications

(10 citation statements)

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“…The results of analyses of poplar [131,132,136] and Linum [137] have led to suggestions that the acropetally differentiating vascular system determines the site of primordium initiation at the SAM, thereby regulating phyllotactic patterning. The importance of the vascular system in phyllotactic pattern formation has recently been re-discovered, but interpretations of its actual function vary [63,127,134].…”

Section: Regulation Of the Phyllotactic Pattern Formation -Similaritimentioning

confidence: 99%

Diversity of phyllotaxis in land plants in reference to the shoot apical meristem structure

Gola

Banasiak

2016

Acta Soc Bot Pol

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Regularity and periodicity in the arrangements of organs in all groups of land plants raise questions about the mechanisms underlying phyllotactic pattern formation. The initiation of the lateral organs (leaves, flowers, etc.), and thus, their spatio-temporal positioning, occurs in the shoot apical meristem (SAM) and is related to the structure and organogenic activity of the meristem. In this review, we present some aspects of the diversity and stability of phyllotactic patterns in the major lineages of land plants, from bryophytes to angiosperms, in which SAM structures differ significantly. In addition, we discuss some of the possible mechanisms involved in the formation of the recurring arrangement of the lateral organs.

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Section: Regulation Of the Phyllotactic Pattern Formation -Similaritimentioning

confidence: 99%

Diversity of phyllotaxis in land plants in reference to the shoot apical meristem structure

Gola

Banasiak

2016

Acta Soc Bot Pol

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“…Thus, the geometric interpretation predicts a correlation between the fraction index of the phyllotaxis order and the trace length represented in internode units. Indeed, it has been remarked as a general rule; the higher phyllotaxis order is with the longer leaf trace (Girolami (1953); Esau (1965)). To conclude, the plant in its maturity, as it were, achieves rational approximations to a divergence angle at the apex in conformity with the leaftrace length in internode units.…”

Section: Discussionmentioning

confidence: 94%

Geometric interpretation of phyllotaxis transition

Okabe

2012

Preprint

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The original problem of phyllotaxis was focused on the regular arrangements of leaves on mature stems represented by common fractions such as 1/2, 1/3, 2/5, 3/8, 5/13, etc. The phyllotaxis fraction is not fixed for each plant but it may undergo stepwise transitions during ontogeny, despite contrasting observation that the arrangement of leaf primordia at shoot apical meristems changes continuously. No explanation has been given so far for the mechanism of the phyllotaxis transition, excepting suggestion resorting to genetic programs operating at some specific stages. Here it is pointed out that varying length of the leaf trace acts as an important factor to control the transition by analyzing Larson's diagram of the procambial system of young cottonwood plants. The transition is interpreted as a necessary consequence of geometric constraints that the leaf traces cannot be fitted into a fractional pattern unless their length is shorter than the denominator times the internode.

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“…This is not because the latter is less important than the former. As a matter of fact, experimental findings on the close relationship between phyllotactic fraction and vascular organization have been accumulated without being theorized from a general perspective (Sterling (1945); Girolami (1953); Jensen (1968); Namboodiri and Beck (1968); Larson (1977); Beck et al (1982); Kirchoff (1984)).…”

Section: Review Background and Motivationmentioning

confidence: 99%

“…The fraction neatly represents geometrical arrangement of leaf traces, and the fractional order need not mean that leaves are positioned exactly vertically. Developmental sequences in differentiation and vascularization of leaf primordia are numerically correlated with the phyllotactic fraction of the shoot (Priestley and Scott (1936); Girolami (1953); Esau (1965)). Seemingly irregular rhythmical variations in various lengths of the external structure of a mature plant may be understood as a consequence of a hidden phyllotactic order in the vascular system (Unruh (1950); Kumazawa and Kumazawa (1971)).…”

Section: Review Background and Motivationmentioning

confidence: 99%

Vascular phyllotaxis transition and an evolutionary mechanism of phyllotaxis

Okabe

2012

Preprint

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Leaves of vascular plants are arranged regularly around stems, a phenomenon known as phyllotaxis. A constant angle between two successive leaves is called divergence angle. On the one side, the divergence angle α 0 of an initial pattern of leaf primordia at a shoot apex is most commonly an irrational number of about 137.5 degrees, called limit divergence. On the other side, the divergence α of a final pattern of leaf traces in the vascular system of a mature stem is expressed in terms of a sequence of rational numbers, 1 2 , 1 3 , 2 5 , 3 8 , 5 13 , 8 21 , called phyllotactic fractions. The mathematical relationship between the initial divergence α 0 , the final divergence α, and the number of internodes traversed by the leaf traces n c is investigated by means of a theoretical model of vascular phyllotaxis. It is shown that continuous changes of the trace length n c induce transitions between the fractional orders in the vascular structure. The vascular phyllotaxis transition suggests an evolutionary mechanism for the phenomenon of phyllotaxis. To provide supporting evidence for the model and mechanism, available experimental results for fossil remains of Lepidodendron and the vascular structure of Linum and Populus are analyzed with the model.

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Relation between Phyllotaxis and Primary Vascular Organization in Linum

Cited by 10 publications

References 0 publications

Diversity of phyllotaxis in land plants in reference to the shoot apical meristem structure

Diversity of phyllotaxis in land plants in reference to the shoot apical meristem structure

Geometric interpretation of phyllotaxis transition

Vascular phyllotaxis transition and an evolutionary mechanism of phyllotaxis

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