Water in Plants — xix — Illustrations 



Figure 38. — The effect of 0.2 M sucrose, 0.2 M sucrose plus 10 mgm. of indole- 

 3-acetic acid per liter, these concentrations of sucrose and auxin plus 10"^ M. 

 KCl, these concentrations of sucrose and auxin plus 10"* M. K fumarate, on 



changes in the wet weight of aerated potato slices 128 



Figure 39. — Effect of auxins on water uptake of potato tissue under sterile and non- 

 sterile conditions 130 



Figure 40. — Apparatus for demonstrating "anaphoresis" 141 



Figure 41. — Diagrammatic representation of two membranes, one permeable to cations 



only, the other, anion permeable 142 



Figure 42. — Electroosmotic flow according to Bennet-Clark and Bexon . . .143 

 Figure 43. — DPD gradient from the root up the stem of Arthrophytum haloxylon 164 

 Figure 44. — Diurnal fluctuation in transpiration and in DPD at different heights on 



the stem of Arthrophytum haloxylon 165 



Figure 45. — DPD measurements on the petioles of squash plants 166 



Figure 46. — DPD values of solutions in the petioles of a squash plant in the 



laboratory 167 



Figure 47. — Arrangement of heating element and thermocouples used by Huber and 



Schmidt for measuring slow rates of movement of sap streams 170 



Figure 48. — Diurnal variation in rate of sap movement in Larix, Picea, and Fagus 171 

 Figure 49. — Potometer with growing plant for study of water absorption and loss 186 

 Figure 50. — Diurnal fluctuation in the wettability of leaf cuticle as shown by change 



in contact angle of water drops 188 



Figure 51. — DPD of the atmosphere at 20°C as related to relative humidity . . 189 

 Figure 52. — Relation between atmospheric temperature and relative humidity for an 



atmosphere containing .004 pounds of water per pound of dry air 190 



Figure 53. — Diurnal fluctuations in DPD of the atmosphere at a station in Wash- 

 ington, D.C., during a 10-day period in June 1932 191 



Figure 54. — Diurnal fluctuations in water loss from rooted Coleus leaves under con- 

 trolled conditions 192 



Figure 55. — The effect of DPD of Chlorella cells upon photosynthesis .... 201 

 Figure 56. — Experimental conditions for demonstrating subaqueous transpiration 204 



Plate illustrating Hales' "Experiments, whereby to find out the force 

 with which trees imbibe moisture." — From his "Vegetable Staticks" 

 (ed. 3, 1738) iv 



Dutrochet's apparatus "pour mesurer la force de I'endosmose." — Plate 

 1 from his "Memoires pour servir a I'Histoire Anatomique et Physi- 

 ologique des Vegetaux et des Animaux" (1837) xxii 



Pfeffer's original apparatus to determine the osmotic pressure of so- 

 lutions. — From his "Osmotischen Untersuchungen" (1877) . . 242 



Vignettes on pages xvii, xxi and 227 and 232 

 from Hales' "Vegetable Staticks". 



