منابع مشابه
Vascular phyllotaxis transition and an evolutionary mechanism of phyllotaxis
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 α0 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...
متن کاملRegulation of phyllotaxis.
Plant architecture is characterized by a high degree of regularity. Leaves, flowers and floral organs are arranged in regular patterns, a phenomenon referred to as phyllotaxis. Regular phyllotaxis is found in virtually all higher plants, from mosses, over ferns, to gymnosperms and angiosperms. Due to its remarkable precision, its beauty and its accessibility, phyllotaxis has for centuries been ...
متن کاملOn geodesics of phyllotaxis
1: Seeds of sunflowers are often modelled by the map n 7−→ φθ(n) = √ ne2iπnθ leading to a roughly uniform repartition with two consecutive seeds separated by the divergence angle 2πθ for θ the golden ratio. We associate to an arbitrary real divergence angle 2πθ a geodesic path γθ : R>0 −→ PSL2(Z)\H of the modular curve and use it for local descriptions of the image φθ(N) of the phyllotactic map...
متن کاملPhysical phenomenology of phyllotaxis.
We propose an evolutionary mechanism of phyllotaxis, regular arrangement of leaves on a plant stem. It is shown that the phyllotactic pattern with the Fibonacci sequence has a selective advantage, for it involves the least number of phyllotactic transitions during plant growth.
متن کاملPhyllotaxis, a model
A model is proposed to account for the positioning of leaf outgrowths from a plant stem. The specified interaction of two signaling pathways provides tripartite patterning. The known phyllotactic patterns are given by intersections of two 'lines' which are at the borders of two determined regions. The Fibonacci spirals, the decussate, distichous and whorl patterns are reproduced by the same sim...
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ژورنال
عنوان ژورنال: New Phytologist
سال: 1902
ISSN: 0028-646X,1469-8137
DOI: 10.1111/j.1469-8137.1902.tb06553.x