TRANSACTIONS
OF THE
BOSE RESEARCH INSTITUTE, CALCUTTA,
VOL. II, 1919
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.
RESPONSE IN THE LIVING AND NON-LIVING.
With 117 Illustrations, 8vo. 10_s._ 6_d._ 1902
PLANT RESPONSE: AS A MEANS OF PHYSIOLOGICAL INVESTIGATION.
With 278 Illustrations, 8vo. 21_s._ 1906
COMPARATIVE ELECTRO-PHYSIOLOGY. A PHYSICO-PHYSIOLOGICAL STUDY.
With 406 Illustrations, 8vo. 15_s._ 1907
RESEARCHES ON IRRITABILITY OF PLANTS.
With 190 Illustrations, 8vo. 10_s._ 6_d._ _net_ 1913
LIFE MOVEMENTS IN PLANTS, VOL. I.
With 92 Illustrations, 8vo. 10_s._ 6_d._ 1918
LONGMANS, GREEN & CO.
London, New York, Bombay and Calcutta.
PREFACE TO 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.
_October 1919._
J. C. BOSE.
CONTENTS.
PART III.
TROPISM IN PLANTS.
XXII.--THE BALANCED CRESCOGRAPH.
PAGE.
Principle of the Method of Balance--Compensating movement--
Growth-scale--Sensitiveness of the Crescographic Balance--
Effect of CO_{2}--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