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epinasty

n. (context botany English) the downward curvature of leaves etc due to differential growth rates

Usage examples of "epinasty".

A young cotyledon or leaf after bursting free is brought down into its proper position, as already remarked, by epinasty, which, according to De Vries, long continues to act on the midribs and petioles.

As this latter movement occurred in complete darkness, and with peduncles arising from upright and from dependent branches, it cannot be due to apheliotropism or to epinasty, but must be attributed to geotropism.

Distinction between heliotropism and the effects of light on the periodicity of the movements of leaves--Heliotropic movements of Beta, Solanum, Zea, and Avena--Heliotropic movements towards an obscure light in Apios, Brassica, Phalaris, Tropaeolum, and Cassia--Apheliotropic movements of tendrils of Bignonia--Of flowerpeduncles of Cyclamen--Burying of the pods--Heliotropism and apheliotropism modified forms of circumnutation--Steps by which one movement is converted into the other--Transversalheliotropismus or diaheliotropism influenced by epinasty, the weight of the part and apogeotropism--Apogeotropism overcome during the middle of the day by diaheliotropism--Effects of the weight of the blades of cotyledons--So called diurnal sleep--Chlorophyll injured by intense light--Movements to avoid intense light SACHS first clearly pointed out the important difference between the action of light in modifying the periodic movements of leaves, and in causing them to bend towards its source.

This apparently was due to epinasty and not to apogeotropism, for the apex, soon after passing the perpendicular, curved so rapidly downwards that we could not doubt that the movement was at least aided by geotropism.

The subpeduncles of the fertilised and withered flowers of Oxalis carnosa likewise bend downwards through epinasty, as will be shown in a future chapter.

We will therefore speak of circumnutation, which is always in progress, as modified by epinasty, hyponasty, geotropism, or other agencies, whether internal or external.