Life Movements in Plants, Volume II

I have in the present volume dealt with the intricate phenomena of different tropisms. The movements in plants under the stimuli of the environment—the twining of tendrils, the effect of temperature, the action of light inducing movements sometimes towards and at other times away from the stimulus, the diametrically opposite responses of the shoot and the root to the same stimulus of gravity, the day and night positions of organs of plants—these, and many others present such diversities that it must have appeared a hopeless endeavour to discover any fundamental reaction applicable in all cases. It has therefore been customary to assume different sensibilities especially evolved for the advantage of the plant. But teleological argument and the use of descriptive phrases, like positive and negative tropism, offer no real explanation of the phenomena. Thus to quote Pfeffer "When we say that an organ curves towards a source of illumination, because of its heliotropic irritability we are simply expressing an ascertained fact in a conveniently abbreviated form, without explaining why such curvature is possible or how it is produced.... Many observers have unfortunately devoted their attention to artificially classifying the phenomenon observed, and have entirely neglected the explanation of causes underlying them." He also adds that in regard to the phenomenon of growth and its variations, an empirical treatment is all that is possible in the present state of our knowledge; but deduction from results of experimental investigation "still remains the ideal of physiology, and only when this ideal has been attained, shall we be able to obtain a comprehensive view of the interacting factors at work in the living organism."

In my previous work on "Plant Response" (1906) I described detailed investigations on irritability of plants which I carried out with highly sensitive recorders. The plant was thus made to tell its own story by means of its self-made records. The results showed that there is no specific difference in physiological reaction of different organs to justify the assumption of positive and negative irritabilities. A generalisation was obtained which gave a complete explanation of diverse movements in plants. The results were fully confirmed by an independent method of inquiry, namely that of electric response, which I have been able to elaborate so as to become a very important means of research.

The investigations described in the present volume not only support the conclusions reached in my earlier works, but have led to important additions. It is evident that the range of our investigation is limited only by our power of recording the rate of plant-movement, that is to say, in the measurement of length and time. In these respects the instruments that I have been able to devise have surpassed my sanguine expectations. The Resonant Recorder traces time-intervals as short as a thousandth part of a second, while my Balanced Crescograph enables us to measure variation of rate of growth as minute as ¹⁄₁₀₀₀ millionth of an inch per second, the sensitiveness of this apparatus thus rivals that of the spectroscope. The increasing refinement in our experimental methods cannot but lead to important advances towards a deeper understanding of underlying reactions in the living organism.

I shall here draw attention to only a few of the important results given in the present volume. The tropic effect of light has been shown to have a definite relation to the quantity of incident light. A complete tropic curve has been obtained from sub-minimal to maximal stimulation which shows the inadequacy of Weber's law, for the sub-minimal stimulus induces a qualitative difference in physiological reaction. It has further been shown that the prevalent idea that perception and heliotropic excitation are two distinct phenomena is without any foundation.

With reference to the effect of ether waves on plants, I have given an account of my discovery of the response of all plants to wireless stimulation, the results being similar to that induced by visible light. The perceptive range of the plant is thus infinitely greater than ours; for it not only perceives, but also responds to different rays of the vast ethereal spectrum.

The results obtained by the method of geo-electric response show that the responsive reaction of the root is in no way different from that of the shoot, the opposite movements being due to the fact that in the shoot the stimulation is direct, and in the root it is indirect.

Full description is given of the new method of physiological exploration by means of the electric probe, by which the particular layer which perceives the stimulus of gravity is definitely localised. The method of electric probe is also found to be of extended application in the detection of physiological changes in the interior of an organ.

An important factor of nyctitropic movements, hitherto unsuspected, is the effect of variation of temperature on geotropic curvature. This and other co-operative factors have been fully analysed, and a satisfactory explanation has been offered of various types of diurnal movement.

A generalisation has been obtained which explains all the diverse movements of plants, under all modes of stimulation: it has been shown that direct stimulation induces contraction and retardation of growth, and that indirect stimulation induces an expansion and acceleration of growth.

Another generalisation of still greater importance is the establishment of identical nature of physiological reaction in the plant and the animal, leading to advances in general physiology. Thus the discovery of a method for immediate enhancement or inhibition of nervous impulse in the plant led to my success in the control of nervous impulse in the animal. Another important discovery was the dual nervous impulses in plants, and I have very recently been able to establish, that the nervous impulse generated in the animal nerve by stimulus is not single, but double.

The study of the responsive phenomena in plants must thus form an integral part of physiological investigation into various problems relating to the irritability of all living tissues, and without such study the investigation must in future remain incomplete.

J. C. BOSE.

October 1919.

CONTENTS.

PART III. TROPISM IN PLANTS.
	PAGE.
XXII.—THE BALANCED CRESCOGRAPH.
Principle of the Method of Balance—Compensating movement—Growth-scale—Sensitiveness of the Crescographic Balance—Effect of CO₂—Effect of anÆsthetics	255
XXIII.—ON TROPIC MOVEMENTS.
Complexity of the problem—Contradictory nature of responses—Two classes of tropic responses—Longitudinal transmission of effect of stimulus—Transverse transmission of effect of stimulus—Modification of tropic curvature by conducting power of tissues and differential excitability of the organ	268
XXIV.—TROPIC CURVATURE WITH LONGITUDINAL TRANSMISSION OF EFFECT OF STIMULUS.
Dual impulses, positive and negative, caused by stimulus—Direct and Indirect stimulus—Tropic effect of Indirect stimulation	271
XXV.—TROPIC CURVATURE WITH TRANSVERSE TRANSMISSION OF EFFECT OF STIMULUS.
Turgor variation under transverse transmission of stimulus-effect—Tropic responses of pulvinated and growing organs to unilateral stimulation—Direct unilateral stimulation—Indirect unilateral stimulation—Difference of effects induced by Direct and Indirect stimulation—Laws of tropic curvature	279
XXVI.—MECHANOTROPISM: TWINING OF TENDRILS.
Anomalies of mechanotropism—Effects of indirect and direct electric stimulation on growth of tendril—Effect of direct and indirect mechanical stimulus—Immediate and after-effect of stimulus—Inhibitory action of stimulus—Response of less excitable side of the tendril—Relative intensities of responses of upper and under sides of tendril of Passiflora—Negative curvature of tendril	288
XXVII.—ON GALVANOTROPISM.
Polar effects of electric current on growth—Effect of anode and cathode on growth	301
XXVIII.—ON THERMONASTIC PHENOMENA.
Effect of temperature—Different thermonastic organs—Two types of response: Positive and Negative—Effect of rise of temperature and of stimulus on thermonastic organs—Law of thermonastic reaction	305
XXIX.—ON PHOTOTROPISM.
Complexity of problem of phototropic reaction—Action of light—Positive phototropic curvature of pulvinated organs—Positive phototropic curvature of growing organs—Phenomenon of recovery—Immediate and after-effect of light on growth—Latent period of phototropic reaction—Growth variation induced by flash of light from a single spark—Maximum positive curvature under continued action of light	313
XXX.—DIA-PHOTOTROPISM AND NEGATIVE PHOTOTROPISM.
Differential excitability of two halves of pulvinus of Mimosa—Transformation of positive to negative curvature—Tropic effect under sunlight—Negative phototropism of shoot and root	328
XXXI.—RELATION BETWEEN THE QUANTITY OF LIGHT AND THE INDUCED PHOTOTROPIC CURVATURE.
Effect of increasing intensity of light on pulvinated and growing organs—Effect of increasing angle—Effect of duration of exposure	338
XXXII.—THE PHOTOTROPIC CURVE AND ITS CHARACTERISTICS.
Summation of stimulus—General consideration—The general characteristic curve—Characteristics of simple phototropic curve—Variation of susceptibility for excitation in different parts of the curve—Effect of sub-minimal stimulus—The complete phototropic curves of pulvinated and growing organs—Limitation of Weber's law	346
XXXIII.—TRANSMITTED EFFECT OF PHOTIC STIMULATION.
Effect of light applied on tip of Setaria—Response of growing region to unilateral stimulus—Effect of simultaneous stimulation of the tip and the hypocotyl—Algebraical summation of effects of direct and indirect stimuli	362
XXXIV.—ON PHOTONASTIC CURVATURES.
Phototropic response of anisotropic organs—Positive para-heliotropism—Negative para-heliotropism—Responses of pulvinated and growing organs to light	378
XXXV.—EFFECT OF TEMPERATURE ON PHOTOTROPIC CURVATURE.
Effect of temperature on excitability—Effect of temperature on conduction—Phototropic response of tendrils—Seasonal variation of phototropic curvature—Antagonistic effects of light and of rise of temperature	388
XXXVI.—ON PHOTOTROPIC TORSION.
Torsional response to light—Effect of different modes of lateral stimulation—Effect of differential excitability on the direction of torsion—Laws of torsional response—Complex torsion under light—Advantages of the Method of Torsional Response—The Torsional Balance—Determination of the direction of stimulus	397
XXXVII.—RADIO-THERMOTROPISM.
Effect of infra-red radiation—Positive radio-thermotropism—Dia-radio-thermotropism—Negative radio-thermotropism	410
XXXVIII.—RESPONSE OF PLANTS TO WIRELESS STIMULATION.
Effects of different rays of spectrum on growth—The wireless system—Mechanical and electrical responses of Mimosa to Hertzian waves—Effect of wireless stimulation on growth of plants	416
XXXIX.—GEOTROPISM.
Direction of the stimulus of gravity—The Geotropic Recorder—Determination of the character of geotropic reaction—Theory of statoliths—Determination of the latent period—The complete geotropic curve—Determination of effective direction of stimulus of gravity—Algebraical summation of effects of geotropic and photic stimulus—Analogy between the effects of stimulus of light and of gravity—Relation between the directive angle and geotropic reaction—Differential geotropic excitability	425
XL.—GEO-ELECTRIC RESPONSE OF SHOOT.
Electric response to direct and indirect stimulation—Experimental arrangement for obtaining geo-electric response—Geo-electric response of the upper and lower sides of the organ—Method of Axial Rotation—Characteristics of geo-electric response—Physiological character of geo-electric response—Effect of differential excitability of the organ—Law determining the relation between angle of inclination and geotropic effect—Method of Vertical Rotation—Electric response through an entire cycle—Relation between angle of vertical rotation and intensity of geo-tropic reaction	442
XLI.—MECHANICAL AND ELECTRICAL RESPONSE OF ROOT TO VARIOUS STIMULI.
Mechanical and electrical response to Direct stimulation—Mechanical and electrical response to Indirect stimulation—Effect of unilateral stimulation applied at the root-tip	461
XLII.—GEO-ELECTRIC RESPONSE OF ROOT.
Geo-electric response of the root-tip—Electric response in the growing region of root—Differential effect between the tip and the growing region—Geo-perception at the root-tip	467
XLIII.—LOCALISATION OF GEO-PERCEPTIVE LAYER BY MEANS OF THE ELECTRIC PROBE.
Principle of the method of electric exploration—The Electric Probe—Electric exploration of the geo-perceptive layer—Geo-electric reaction at different depths of tissues—Microscopical examination of the maximally excited layer—Influence of season on geo-electric response—Tests of insensitive specimens—Reaction at lower side of the organ—The Method of Transverse Perforation	478
XLIV.—ON GEOTROPIC TORSION.
Arrangement for torsional response—Algebraical summation of geotropic, and phototropic effects—Balance of geotropic by phototropic action—Comparative balancing effects of white and red lights—Effect of coal gas on photo-geotropic balance	503
XLV.—ON THERMO-GEOTROPISM.
Necessary conditions for geotropic curvature—Modifying influence of temperature on geotropic curvature—Magnetic analogue—Tropic equilibrium under varying intensities of stimulus—Effect of variation of temperature on geotropic torsion—Variation of apo-geotropic curvature under thermal change—Effect of variation of temperature on dia-geotropic equilibrium	509
PART IV. NIGHT AND DAY MOVEMENTS IN PLANTS.

XLVI.—DIURNAL MOVEMENTS IN PLANTS.
Complexity of the problem—The different factors involved—Autonomous movements—Epinasty and hyponasty—Positive and negative thermonasty—Thermo-geotropism—Classification of diurnal movements—Discriminating tests for classification—Diurnal variation of light and of temperature	523
XLVII.—DIURNAL MOVEMENT DUE TO ALTERNATION OF LIGHT AND DARKNESS.
Experimental arrangements—The Quadruplex Nyctitropic Recorder—Diurnal movement of the leaflet of Cassia alata—Effect of variation of temperature—Effect of variation of light—Diurnal movement of the terminal leaflet of Desmodium gyrans—The 'midday sleep'	535
XLVIII.—DIURNAL MOVEMENT DUE TO VARIATION OF TEMPERATURE AFFECTING GROWTH.
Tropic and nastic movements—Distinction between thermonastic and thermo-geotropic action—Diurnal movement of NymphÆa—Action of light—Effect of variation of temperature	546
XLIX.—DAILY MOVEMENT IN PLANTS DUE TO THERMO-GEOTROPISM.
Characteristics of thermo-geotropic movements—Diurnal movement of Palm trees—Diurnal movement of procumbent stems and of leaves—Continuous diurnal record for successive thermal noon—Modification of the diurnal curve—Effect of fluctuation of temperature—Effect of restricted pliability of the organ—Effect of age—Effect of season—Reversal of the normal rhythm—Effect of constant temperature—Diurnal movement in inverted position	554
L.—THE AFTER-EFFECT OF LIGHT.
Electric after-effect of light—After-effect at pre-maximum, maximum, and post-maximum—Tropic response under light, and its after-effects at pre-maximum, maximum, and post-maximum	569
LI.—THE DIURNAL MOVEMENT OF THE LEAF OF MIMOSA.
Four different phases in the diurnal record of Mimosa—Different factors determining its diurnal movement—Diurnal variation of geotropic torsion—Autonomous pulsation of the leaf of Mimosa—The Photometric Recorder—Effect of direct light—The evening spasmodic fall of the leaf—Diurnal movement of the amputated petiole—Diurnal curve of the petiole of Cassia alata—Response of Mimosa to darkness at different parts of the day—After-effect of light at pre-maximum, maximum, and post-maximum	576

ILLUSTRATIONS.

FIGURE.		PAGE.
93.	Arrangement for compensation of growth-movement by equal subsidence of plant-holder	257
94.	Photograph of the Balanced Crescograph	258
95.	Balanced Crescographic record	260
96.	Record showing the effect of CO₂	265
97.	Effect of ether and of chloroform	266
98.	Diagrammatic representation of effects of Indirect and Direct stimulation	275
99.	Tropic curvature of Crinum	276
100.	Turgor variation caused by Indirect stimulation	281
101.	Response of Mimosa leaf under transverse transmission of effect of electric stimulus	282
102.	Diagrammatic representation of Indirect and Direct stimulation of tendril	290
103.	Record by Method of Balance	291
104.	Variation of growth under direct stimulation	292
105.	Positive curvature of tendril of Cucurbita	295
106.	Diagrammatic representation of effects of Indirect and Direct unilateral stimulation of tendril	296
107.	Retardation of rate of growth under cathode	303
108.	Acceleration of rate of growth under anode	303
109.	Thermonastic and radionastic responses of petal of Zephyranthes	308
110.	The Thermonastic Recorder	309
111.	Negative thermonastic response of NymphÆa	310
112.	Successive positive responses of the terminal leaflet of bean plant	317
113.	Positive response and recovery under moderate phototropic stimulation	318
114.	Persistent positive curvature under stronger stimulation	318
115.	Immediate and after-effect of stimulus of light on growth	320
116.	Latent period for photic stimulation	324
117.	Effect of a single electric spark on growth	325
118.	Responses of Mimosa leaf to light from above	330
119.	Responses of Mimosa leaf to light from below	330
120.	Record of effect of continuous application of light on upper half of pulvinus of Mimosa	331
121.	Positive and negative phototropic response of Oryza	335
122.	Leaf of Desmodium gyrans	339
123.	The Oscillating Recorder	340
124.	Tropic effect of increasing intensity of light on the leaflet of Desmodium gyrans	341
125.	Tropic effect of increasing intensity of light on growing organ (Crinum)	341
126.	The Collimator	342
127.	Effect of angle of inclination of light on tropic curvature of pulvinated organ	343
128.	Effect of angle of inclination on growth-curvature	343
129.	Effect of increasing duration of exposure to light	344
130.	Effect of continuous electric and photic stimulation on rate of growth	348
131.	Characteristic curve of iron	351
132.	Simple characteristic curve of phototropic reaction	351
133.	Complete phototropic curve of pulvinated organ	358
134.	Complete phototropic curve of growing organ	359
135.	Arrangement for local application of light	367
136.	Response of seedling of Setaria to light	368
137.	Effect of application of light to the growing hypocotyl of Setaria	370
138.	Response to direct and indirect photic stimulus	373
139.	Diagrammatic representation of the effects of direct and indirect stimulation of Setaria	375
140.	Photonastic curvature of creeping stem of Mimosa pudica	380
141.	Positive phototropic response of Erythrina indica	382
142.	Response of leaflet of Mimosa to light	383
143.	Response of leaflet of Averrhoa to light	383
144.	Diagrammatic representation of different types of phototropic response	384
145.	Phototropic curvature of tendril of Passiflora	392
146.	Effect of rise of temperature on phototropic curvature	394
147.	After-effect of rise of temperature	395
148.	Arrangement for record of torsional response	399
149.	Record of torsional response of pulvinus of Mimosa pudica	400
150.	Leaflets of Cassia alata	404
151.	Positive response to thermal radiation	413
152.	Record of positive, neutral, and reversed negative curvature under thermal radiation	414
153.	Diagrammatic representation of the wireless system	419
154.	Mechanical response of Mimosa leaf to electric waves	420
155.	Electric response of Mimosa to Hertzian wave	420
156.	Record of responses of growing organs to wireless stimulation	422
157.	The Quadruplex Geotropic Recorder	428
158.	Effect of alternate application of cold on upper and lower sides of the organ	430
159.	Geotropic response of flower stalk of Tube-rose	433
160.	Geotropic response of TropÆolum	433
161.	The Complete Geotropic Curve	435
162.	Diagrammatic representation of photic and geotropic stimulation	436
163.	The effect of super-imposition of photic stimulus	436
164.	Diagrammatic representation of the mechanical and electrical response	443
165.	Diagrammatic representation of geo-electric response	447
166.	Diagrammatic representation of Methods of Axial and Vertical Rotation	449
167.	Diagrammatic representation of the geo-electric response of the shoot	450
168.	Geo-electric response of the petiole of TropÆolum	452
169.	Geo-electric response of the scape of Uriclis	453
170.	Mechanical and electric response to indirect stimulation	463
171.	Diagrammatic representation of mechanical and electric response of root	464
172.	Diagrammatic representation of geo-electric response of root-tip	469
173.	Diagrammatic representation of geo-electric response of growing region of root	471
174.	Diagrammatic representation of the geo-perceptive layer	480
175.	The Electric Probe	483
176.	Transverse section showing continuous geo-perceptive layer (Bryophyllum)	488
177.	Curve of geo-electric excitation in different layers of NymphÆa	497
178.	Curve of geo-electric excitation in Bryophyllum	497
179.	Diagram of arrangement of geotropic torsional response	503
180.	Additive effect of stimulus of gravity and light	505
181.	Algebraical summation of geotropic and phototropic actions	505
182.	Comparative balancing effects of white and red lights	506
183.	Effect of coal gas on photo-geotropic balance	507
184.	Diagram of magnetic balance	511
185.	Effect of variation of light on phototropic equilibrium	512
186.	Effect of variation of temperature on geotropic torsion	514
187.	Simultaneous records of variation of temperature, on up and down movement, and of torsion of the leaf of Mimosa	518
188.	Arrest of pulsatory movement of leaflet of Desmodium gyrans by light	528
189.	Effect of unilateral light on hyponastic movement	529
190.	The Nyctitropic Recorder	537
191.	Effect of sudden darkness on leaflet of Casia alata	539
192.	Diurnal movement of the leaflet of Cassia alata	540
193.	The day and night position of the petiole and terminal leaflet of Desmodium gyrans	541
194.	Diurnal record of the terminal leaflet of Desmodium gyrans	542
195.	Photograph of closed flower of NymphÆa during day	550
196.	Photograph of open flower of NymphÆa at night	550
197.	Action of light on the petal of NymphÆa	551
198.	Diurnal movement of the petal of NymphÆa	552
199.	Diurnal record of the Sijbaria Palm	556
200.	Diurnal record of inclined Palm, geotropically curved procumbent stem of TropÆolum, and dia-geotropic leaf of Palm	557
201.	Diurnal record of leaves of Dahlia, Papya, and Croton	558
202.	Diurnal record of procumbent stem of TropÆolum, and leaf of Dahlia for two successive days	560
203.	Abolition of the diurnal movement under constant temperature (TropÆolum)	565
204.	Effect of inversion of plant on diurnal movement of TropÆolum	567
205.	Electric response of the leaf stalk of Bryophyllum under light	571
206.	Diagrammatic representation of electric after-effect of photic stimulation	571
207.	After-effect of pre-maximum photic stimulation	574
208.	After-effect of maximum photic stimulation	574
209.	After-effect of post-maximum photic stimulation	574
210.	Diurnal record of Mimosa in summer and winter	577
211.	Record of diurnal variation of torsion in Mimosa leaf	582
212.	Continuous record of automatic pulsation of Mimosa leaf	585
213.	Photometric record showing variation of intensity of light from morning to evening	586
214.	Record of leaf of Mimosa after amputation of sub-petioles	589
215.	Diurnal record of Cassia leaf	591
216.	Post-maximum after-effect of light on response of leaflet of Cassia	592
217.	Effect of periodic alternation of light and darkness on response of Clyx.com

LIFE MOVEMENTS IN PLANTS

BY

SIR JAGADIS CHUNDER BOSE, Kt., M.A., D.Sc., C.S.I., C.I.E.,

PROFESSOR EMERITUS, PRESIDENCY COLLEGE, DIRECTOR, BOSE RESEARCH INSTITUTE,

WITH 128 ILLUSTRATIONS

CALCUTTA BENGAL GOVERNMENT PRESS 1919 PUBLISHED BY THE BOSE RESEARCH INSTITUTE, CALCUTTA.

WORKS BY THE SAME AUTHOR.

PREFACE TO VOLUME II.

CONTENTS.

ILLUSTRATIONS.

PROFESSOR EMERITUS, PRESIDENCY COLLEGE,
DIRECTOR, BOSE RESEARCH INSTITUTE,

CALCUTTA
BENGAL GOVERNMENT PRESS
1919

PUBLISHED BY
THE BOSE RESEARCH INSTITUTE, CALCUTTA.