Anatomy and Movement of The Column in Stylidium

Abstract

The flower of the trigger-plant Stylidium has stamens and style fused into a single column. A bend in the column, upon suitable stimulation by nectar-gathering insects, reverses its curvature in 10-30 ms, depending on species, causing the column to flip rapidly through an angle of 2-5 radians from its normal position against the anterior modified petal, the labellum, until it comes to rest against the posterior petals. This rapid movement or 'firing' provides a mechanism for cross-fertilization of the flowers. The column, after this rapid excursion then slowly resets to its original position in times from 200 to 700 s. Detailed measurements of the time courses of firing and resetting in several species of Stylidium have been made. During the firing, except for a short period of 1-10 ms in which it accelerates from rest under a force up to 50 g, the column moves with approximately constant angular velocity. This characteristic linear behaviour contrasts markedly with the distinctly non-linear time course of resetting. The dependence of firing and resetting rates on temperature has been investigated. A light-microscope study of the anatomy of the column shows that the mobile bend region possesses an internal anatomy strikingly different from the rest of the column. The bend consists of an inner core of three distinct longitudinal layers of thick-walled collenchymatous cells, surrounded by parenchymatous cells. A model in which changes in length pf the anatomically posterior outer layer of the core are greater than in the other layers is proposed to account for the movement of the column.

The evolution of staminodes in angiosperms: patterns of stamen reduction, loss, and functional re‐invention

“…In flowers without staminodes, such as Chamaepericlymenum (Cornaceae; Mosquin, 1985), sunbird-pollinated Loranthaceae (Feehan, 1985), Hyptis (Lamiaceae; Brantjes and De Vos, 1981;Keller and Armbruster, 1989), Kalmia (Ericaceae: Henshaw, 1915) and some Fabaceae (Medicago, Genista, Ulex, and Sarothamnus-Arroyo, 1981;Proctor and Yeo, 1992), the corolla encloses the stamens and/or style and acts as a trigger. In these flowers, the bent region of the column (comprising anthers and stigmas) is strongly reinforced by layers of thick-walled cells, which produce a rapid movement of the column after contact by a pollinator (Findlay and Findlay, 1975). In these flowers, the bent region of the column (comprising anthers and stigmas) is strongly reinforced by layers of thick-walled cells, which produce a rapid movement of the column after contact by a pollinator (Findlay and Findlay, 1975).…”

“…Rarely, tension is provided by the exploding organ itself, as in Stylidium (Stylidiaceae-Erbar, 1992). In these flowers, the bent region of the column (comprising anthers and stigmas) is strongly reinforced by layers of thick-walled cells, which produce a rapid movement of the column after contact by a pollinator (Findlay and Findlay, 1975).…”

Calcium and plant action potentials

“…Sibaoka, 1966), movement of the column of the flower of Stylidium (e.g. Findlay & Findlay, 1975) or closing of the trapdoor of the bladder of Utricularia (e.g. Sydenham & Findlay, 1973).…”

The Role of Electricity in Plant Movements

“…Stimulation of the region around the base of the column causes a rapid loss of K+ and Cl^ from the motor cells, sufficient to account for the corresponding water loss. There has been no published account of electrical activity associated with this movemetit, but electrical shocks also initiate movement (Kabasch, 1861;Findlay and Findlay, 1975), although this alone cannot be taken as proof of mediation by endogenous electrical signals. On the basis of investigations on Berberis, Sparmannia, Mahonia and Incarvillea it is likely that many, if not all, seismonastic floral movements are mediated by electrical impulses, but so far this prospect has not been fully explored.…”

“…5 min 1-2-2 s Not less Sinyukhin & Britikov, 1965a, b Millet, 1976Sibaoka, 1966 Eondeville, Borthwick & Hendricks, 1966Franck & Auger, 1932 Gregory and Pearse, 1937 than 1 min (-. 1 mm 1-4 min 1 42 s Up to 20 s 0-8 s 0-01 s Williams, 1949Williams, 1948Racusen & Etherton, 1975Diannelidis & Umrath, 1953Bunning, 1934Findlay & Findlay, 19750-015-0-027 sFindlay & Findlay, 1975 0-006 s 10 s Stomatal opening 3-5 min Sartorius musek contraction 0-0028 0-003 s Lloyd, 1942Raschke, 1972Raschke, 1970Sandow, 1944 Electricity in plant movements 13 gross exaggeration in popular literature. By describing the likely functions of electrical activity in reversible plant movements (that is, movements that can be performed more than once by the same motor organ), I hope to show that the plant kingdom has successfully exploited an electrical means of communication in many varied ways.…”