Life Movements in Plants, Volume Ii

PART III.. Tropism in Plants.

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

PART IV.. Night and Day Movements in Plants.

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 CO_{2} 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

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