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Title: The Power of Movement in Plants

 

Author: Charles Darwin

 

Release Date: May, 2004 [EBook #5605]

[Most recently updated: August 14, 2002]

 

Edition: 11

 

Language: English

 

Character set encoding: ASCII

 

*** START OF THE PROJECT GUTENBERG EBOOK, THE POWER OF MOVEMENT IN PLANTS ***

 

This eBook was produced by Sue Asscher.

 

[page i.]

 

THE

 

POWER OF MOVEMENT

 

IN

 

PLANTS.

 

[page ii.]

 

[page iii.]

 

THE

 

POWER OF MOVEMENT

 

IN

 

PLANTS.

 

BY CHARLES DARWIN, LL.D., F.R.S.

 

ASSISTED BY

 

FRANCIS DARWIN.

 

[page iv.]

 

[page v.]

 

CONTENTS.

–—

INTRODUCTION…Page 1-9.

 

CHAPTER I.

 

THE CIRCUMNUTATING MOVEMENTS OF SEEDLING PLANTS.

 

Brassica oleracea, circumnutation of the radicle, of the arched hypocotyl whilst still buried beneath the ground, whilst rising above the ground and straightening itself, and when erect—Circumnutation of the cotyledons—

Rate of movement—Analogous observations on various organs in species of Githago, Gossypium, Oxalis, Tropaeolum, Citrus, Aesculus, of several Leguminous and Cucurbitaceous genera, Opuntia, Helianthus, Primula, Cyclamen, Stapelia, Cerinthe, Nolana, Solanum, Beta, Ricinus, Quercus, Corylus, Pinus, Cycas, Canna, Allium, Asparagus, Phalaris, Zea, Avena, Nephrodium, and Selaginella…10-66

 

CHAPTER II.

 

GENERAL CONSIDERATIONS ON THE MOVEMENTS AND GROWTH OF SEEDLING PLANTS.

 

Generality of the circumnutating movement—Radicles, their circumnutation of service—Manner in which they penetrate the ground—Manner in which hypocotyls and other organs break through the ground by being arched—

Singular manner of germination in Megarrhiza, etc.—Abortion of cotyledons-

-Circumnutation of hypocotyls and epicotyls whilst still buried and arched-

-Their power of straightening themselves—Bursting of the seed-coats—

Inherited effect of the arching process in hypo-

[page vi.]

gean hypocotyls—Circumnutation of hypocotyls and epicotyls when erect—

Circumnutation of cotyledons—Pulvini or joints of cotyledons, duration of their activity, rudimentary in Oxalis corniculata, their development—

Sensitiveness of cotyledons to light and consequent disturbance of their periodic movements—Sensitiveness of cotyledons to contact…Page 67-128

 

CHAPTER III.

 

SENSITIVENESS OF THE APEX OF THE RADICLE TO CONTACT AND TO OTHER IRRITANTS.

 

Manner in which radicles bend when they encounter an obstacle in the soil—

Vicia faba, tips of radicles highly sensitive to contact and other irritants—Effects of too high a temperature—Power of discriminating between objects attached on opposite sides—Tips of secondary radicles sensitive—Pisum, tips of radicles sensitive—Effects of such sensitiveness in overcoming geotropism—Secondary radicles—Phaseolus, tips of radicles hardly sensitive to contact, but highly sensitive to caustic and to the removal of a slice—Tropaeolum—Gossypium—Cucurbita—Raphanus—Aesculus, tip not sensitive to slight contact, highly sensitive to caustic—Quercus, tip highly sensitive to contact—Power of discrimination—Zea, tip highly sensitive, secondary radicles—Sensitiveness of radicles to moist air—

Summary of chapter…129-200

 

CHAPTER IV.

 

THE CIRCUMNUTATING MOVEMENTS OF THE SEVERAL PARTS OF MATURE PLANTS.

 

Circumnutation of stems: concluding remarks on—Circumnutation of stolons: aid thus afforded in winding amongst the stems of surrounding plants—

Circumnutation of flower-stems—Circumnutation of Dicotyledonous leaves—

Singular oscillatory movement of leaves of Dionaea—Leaves of Cannabis sink at night—Leaves of Gymnosperms—Of Monocotyledons—Cryptogams—Concluding remarks on the circumnutation of leaves; generally rise in the evening and sink in the morning…201-262

[page vii.]

 

CHAPTER V.

 

MODIFIED CIRCUMNUTATION: CLIMBING PLANTS; EPINASTIC AND HYPONASTIC

MOVEMENTS.

 

Circumnutation modified through innate causes or through the action of external conditions—Innate causes—Climbing plants; similarity of their movements with those of ordinary plants; increased amplitude; occasional points of difference—Epinastic growth of young leaves—Hyponastic growth of the hypocotyls and epicotyls of seedlings—Hooked tips of climbing and other plants due to modified circumnutation—Ampelopsis tricuspidata—

Smithia Pfundii—Straightening of the tip due to hyponasty—Epinastic growth and circumnutation of the flower-peduncles of Trifolium repens and Oxalis carnosa…Page 263-279

 

CHAPTER VI.

 

MODIFIED CIRCUMNUTATION: SLEEP OR NYCTITROPIC MOVEMENTS, THEIR USE: SLEEP

OF COTYLEDONS.

 

Preliminary sketch of the sleep or nyctitropic movements of leaves—

Presence of pulvini—The lessening of radiation the final cause of nyctitropic movements—Manner of trying experiments on leaves of Oxalis, Arachis, Cassia, Melilotus, Lotus and Marsilea and on the cotyledons of Mimosa—Concluding remarks on radiation from leaves—Small differences in the conditions make a great difference in the result - Description of the nyctitropic position and movements of the cotyledons of various plants—

List of species—Concluding remarks—Independence of the nyctitropic movements of the leaves and cotyledons of the same species—Reasons for believing that the movements have been acquired for a special purpose…280-316

 

CHAPTER VII.

 

MODIFIED CIRCUMNUTATION: NYCTITROPIC OR SLEEP MOVEMENTS OF LEAVES.

 

Conditions necessary for these movements—List of Genera and Families, which include sleeping plants—Description of the movements in the several Genera—Oxalis: leaflets folded at

[page viii.]

night—Averrhoa: rapid movements of the leaflets—Porlieria: leaflets close when plant kept very dry—Tropaeolum: leaves do not sleep unless well illuminated during day—Lupinus: various modes of sleeping—Melilotus: singular movements of terminal leaflet—Trifolium—Desmodium: rudimentary lateral leaflets, movements of, not developed on young plants, state of their pulvini—Cassia: complex movements of the leaflets—Bauhinia: leaves folded at night—Mimosa pudica: compounded movements of leaves, effect of darkness—Mimosa albida, reduced leaflets of—Schrankia: downward movement of the pinnae—Marsilea: the only cryptogam known to sleep—Concluding remarks and summary—Nyctitropism consists of modified circumnutation, regulated by the alternations of light and darkness—Shape of first true leaves…Page 317-417

 

CHAPTER VIII.

 

MODIFIED CIRCUMNUTATION: MOVEMENTS EXCITED BY LIGHT.

 

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 flower-peduncles of Cyclamen—Burying of the pods—Heliotropism and apheliotropism modified forms of circumnutation—

Steps by which one movement is converted into the other—

Transversal-heliotropismus 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…418-448

 

CHAPTER IX.

 

SENSITIVENESS OF PLANTS TO LIGHT: ITS TRANSMITTED EFFECTS.

 

Uses of heliotropism—Insectivorous and climbing plants not heliotropic—

Same organ heliotropic at one age and not at another—Extraordinary sensitiveness of some plants to light—The effects [page ix.]

of light do not correspond with its intensity—Effects of previous illumination—Time required for the action of light—After-effects of light—Apogeotropism acts as soon as light fails—Accuracy with which plants bend to the light—This dependent on the illumination of one whole side of the part—Localised sensitiveness to light and its transmitted effects—Cotyledons of Phalaris, manner of bending—Results of the exclusion of light from their tips—Effects transmitted beneath the surface of the ground—Lateral illumination of the tip determines the direction of the curvature of the base—Cotyledons of Avena, curvature of basal part due to the illumination of upper part—Similar results with the hypocotyls of Brassica and Beta—Radicles of Sinapis apheliotropic, due to the sensitiveness of their tips—Concluding remarks and summary of chapter—

Means by which circumnutation has been converted into heliotropism or apheliotropism…Page 449-492

 

CHAPTER X.

 

MODIFIED CIRCUMNUTATION: MOVEMENTS EXCITED BY GRAVITATION.

 

Means of observation—Apogeotropism—Cytisus—Verbena—Beta—Gradual conversion of the movement of circumnutation into apogeotropism in Rubus, Lilium, Phalaris, Avena, and Brassica—Apogeotropism retarded by heliotropism—Effected by the aid of joints or pulvini—Movements of flower-peduncles of Oxalis—General remarks on apogeotropism—Geotropism—

Movements of radicles—Burying of seed-capsules—Use of process—Trifolium subterraneum—Arachis—Amphicarpaea—Diageotropism—Conclusion…493-522

 

CHAPTER XI.

 

LOCALISED SENSITIVENESS TO GRAVITATION, AND ITS TRANSMITTED EFFECTS.

 

General considerations—Vicia faba, effects of amputating the tips of the radicles—Regeneration of the tips—Effects of a short exposure of the tips to geotropic action and their subsequent amputation—Effects of amputating the tips obliquely—Effects of cauterising the tips—Effects of grease on the tips—Pisum

[page x.]

sativum, tips of radicles cauterised transversely, and on their upper and lower sides—Phaseolus, cauterisation and grease on the tips—Gossypium—

Cucurbita, tips cauterised transversely, and on their upper and lower sides—Zea, tips cauterised—Concluding remarks and summary of chapter—

Advantages of the sensibility to geotropism being localised in the tips of the radicles…Page 523-545

 

CHAPTER XII.

 

SUMMARY AND CONCLUDING REMARKS.

 

Nature of the circumnutating movement—History of a germinating seed—The radicle first protrudes and circumnutates—Its tip highly sensitive—

Emergence of the hypocotyl or of the epicotyl from the ground under the form of an arch—Its circumnutation and that of the cotyledons—The seedling throws up a leaf-bearing stem—The circumnutation of all the parts or organs—Modified circumnutation—Epinasty and hyponasty—Movements of climbing plants—Nyctitropic movements—Movements excited by light and gravitation—Localised sensitiveness—Resemblance between the movements of plants and animals—The tip of the radicle acts like a brain…546-573

 

INDEX…574-593

 

[page 1]

 

THE MOVEMENTS OF PLANTS.

 

INTRODUCTION.

 

THE chief object of the present work is to describe and connect together several large classes of movement, common to almost all plants. The most widely prevalent movement is essentially of the same nature as that of the stem of a climbing plant, which bends successively to all points of the compass, so that the tip revolves. This movement has been called by Sachs “revolving nutation;” but we have found it much more convenient to use the terms circumnutation and circumnutate. As we shall have to say much about this movement, it will be useful here briefly to describe its nature. If we observe a circumnutating stem, which happens at the time to be bent, we will say towards the north, it will be found gradually to bend more and more easterly, until it faces the east; and so onwards to the south, then to the west, and back again to the north. If the movement had been quite regular, the apex would have described a circle, or rather, as the stem is always growing upwards, a circular spiral. But it generally describes irregular elliptical or oval figures; for the apex, after pointing in any one direction, commonly moves back to the opposite side, not, however, returning along the same line. Afterwards other irregular ellipses or ovals are successively described, with their longer [page 2]

axes directed to different points of the compass. Whilst describing such figures, the apex often travels in a zigzag line, or makes small subordinate loops or triangles. In the case of leaves the ellipses are generally narrow.

 

Until recently the cause of all such bending movements was believed to be due to the increased growth of the side which becomes for a time convex; that this side does temporarily grow more quickly than the concave side has been well established; but De Vries has lately shown that such increased growth follows a previously increased state of turgescence on the convex side.* In the case of parts provided with a so-called joint, cushion or pulvinus, which consists of an aggregate of small cells that have