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