690 



SUBJECT INDEX 



Periodicity, daily, 



of absorption of water, 291-293 



of growth, 643-645 



of photosynthesis, 362-363 



of stomatal opening, 1 87-1 90 



of transpiration, 204-211 

 Perisperm, 626 

 Permeability, 117 



and rate of absorption, 127 



of cell walls, 126-127, 207-208 



of cytoplasmic membranes, 119- 

 126, 406-407 



mechanism of changes in, 131 



theories of, 1 28-1 31 

 Peroxidases, 532-533 

 pH, 



of acids and bases, 18 



of cell sap, 79, 80 



of cytoplasm, 80 



of guard cells, 185, 187 



of water, 16, 18 



relation to hydrogen ion concentra- 

 tion, 15-18 

 pH, effect of, 



on enzymatic reactions, 473-474 



on imbibition, 1 14 



on starch-sugar equilibrium, 387 

 Phenolases, 534 

 Phloem, 157, 217-220, 270-272, 481- 



486, 560-561 

 Phloem, internal, 482 

 Phloem, primary, 217, 270, 482, 560 

 Phloem, secondary, 217-219, 220, 



224, 272, 560, 561 

 Phloem exudation, 500-501 

 Phloem fibers, 484 

 Phloem parenchyma, 483, 484, 485 

 Phloem rays, 228, 485 

 Phospholipids, 71, 72, 395, 399 

 Phosphoproteins, 477 

 Phosphorus, role of, 421 

 Photonasty, 664-665 

 Photons, 306 

 Photoperiodism, 601-607 

 Photosynthesis, 319-320 



apparent, 324-325 



daily variations in, 362-363 



Photosynthesis — Continued 



effect of accumulation of products 

 on, 362 



effect of anaesthetics on, 360 



effect of chlorophyll content on, 

 360-361 



effect of deficiency of mineral ele- 

 ments on, 359 



effect of intermittent light on, 329- 

 330 



effect of oxygen on, 359 



effect of protoplasmic factors on, 

 328, 361-362 



effect of temperature on, 354-357 



effect of time factor on, 355-357 



effect of water on, 357-359 



efficiency of, 333-334 



formaldehyde theory of, 331-332 



induction period, 354 



magnitude of, 3>l,yi,3,^ 



measurement of, 324-326 



products of, 321-322 



relation of leaf anatomy to, 320- 

 ^321, 361 



role of carbon dioxide in, 341-343 



role of enzymes in, 330-33 1 



role of light in, 347-354, 357 



steps in the process, 328-329 



theory of Willstatter and Stoll, 



332-333 

 Photosynthetic ratio, 322-323 

 Photosynthetic-respiratory ratio, 527- 



528, 594 

 Phototropism, 655-660 

 Phyllocaline, 583 



Physiological preconditioning, 61 1-612 

 Phytohormones, 572 

 Phytol, 308, 309 

 Phytosterols, 71, 72, 396 

 Pits in cell walls, 221, 222, 223, 224- 



226, 229, 484 

 Plant cells, 



as osmotic systems, 134 



buffer action in, 80-81 



classification of parts of, 62 



forms, 63 



origin of, 62-63 



