456 



SUBJECT INDEX 



Paeonia: 419 



seedling production, 113-117 

 Paleacrita vernata: (See Canl£erworm) 

 Panicum sanguinale: dormancy and germination of, 



128 

 Papaver, 42 



I'arthenocarpy: growth substances effects, 218-220 

 I'article size of fungicides: determination, 366 

 Pea seed decay: method for evaluating seed treat- 

 ments, .379 

 Peach yellows: incubation period, 12 

 not transmitted by pollen, 14 

 studies, 12-14 

 symptoms, 10 

 Peats: pH, 425-426 



phosphorus content, 426 

 to improve composts, 425 

 Pentane: injury to plants, 179-180 

 Pentathionic acid: role in fungicidal action of sul- 

 phur, 362-363 

 Peroxidase: changes in relation to respiration rate, 



249 

 Pesfalotia stellala: 197 



effect of sulphuric acid and hydrogen sulphide on 

 germination of spores, 363-366 

 Petunia, 80 

 Phacelia, 75, 76 

 Phalaris, 35, 205 

 Phaseolus vulgaris, 416 

 Phenols: effects on growth of tomato plants, 178 



toxic effects on houseflies, 354 

 Phenoxy compounds: (See Growth substances) 

 Phenoxyacetic acid, 209 

 a-(Phenoxy)-n-butyric acid, 209, 218 

 |3-(Phenoxy)-propionic acid, 209, 218 

 Phenyl compounds: ultraviolet effects, 323 

 Phenylacetic acid, 207 

 Phenylacrylic acid, 207 

 a-(Phenyl)-propionic acid, 207 



Pbilaenus leucophthalmus: peach yellows carrier, 12 

 Phlegethontius quinquemaculala: nicotine toxicity, 



344 

 Phleum, 35 



Phosphate, colloidal: fertilizer value, 428 

 Phosphorus: content in peat, 426 

 Photoperiodism: effects on plants, 286-309 

 Photosjnthesis: increased by CO2 enrichment of 



air, 285 

 Physocarpus, 00 

 Phyteuma, 41, 42 



Phytohormones: (See Growth substances) 

 Phytolacca, 35 



Phytomyza ilicicola: control, 357 

 Phytophthora iiifestans: use in greenhouse tests of 



fungicides on tomato, 374-378 

 Ph}i;otoxicity: determination of, in fungicide testa, 



379 

 Picea, 90, 102 



Pigment production: La apples, 320, 321 

 Pinus, 90-91, 102 

 Pinua caribaea, 102 

 Pinus ecldnata, 102 

 Pinus palustris, 102 

 Pinus rigida, 102, 103, 130 

 Pinus Taeda, 102 



Piper cubeba: as an insecticide, 354 

 Piper nigrum: as an insecticide, 354 

 Piperine: as an insecticide, 351-352 



effects on muscles of houseflies, 352 

 Plantago, 34, 35, 30, 37, 40, 42 

 Plantago major, 11 



Plants grown under controlled environmental con- 

 ditions, 285-340 

 Poa, 35, 40, 75, 70, 78 

 Pollen: germination, storage, 429-430 

 Pollen storage: Amaryllis, 429^30 

 Cinchona, 429-430 



Gladiolus, 429-430 

 Lilium, 429-430 

 Polygonatum commutatum: dormancy and germina- 

 tion of seeds, 120-121 

 Polygonum, 34, 35, 36, 37, 40, 42, 91 

 Polysaccharides: diurnal changes in leaves, 411-412 

 Popillia japonica: larvae control by /3,/3'-dichloro- 



ethyl ether fumigation, 256-257 

 Populus sp.: as an insecticide, 354 

 Porthetria dispar: pyrethrum toxicity, 348 

 Portulaca, 35, 36, 37, 40 

 Portulaca oleracea: dormancy and germination of, 



128 

 Potamogeton, 21, 43 

 Potamogeton foliosus: 15 



sea-water tolerance, 20 

 Potamogeton pectinatus: 15, 20, 21, 22, 23, 26 



sea- water tolerance, 20 

 Potamogeton perfoliatus: 15, 20, 26 



sea-water tolerance, 20 

 Potassium thiocyanate effects on: amylase activity, 



250 

 Potato: (See Solanum tuberosum) 

 Potato chips: color related to sugar content, 386- 

 398 

 effect of frying temperature on color, 388 

 factors for color, 386-398 

 Potato tubers: as affected by growthsubstances, 212 



(See also Dormancy) 

 Potentilla, 35, 42 

 Primula, 41, 42, 43 

 Privet: (See Ligustrum) 

 Proliferation of plant tissue: ethylene effects, 14S- 



150 

 Propagation: Lycopodium, 434-435 

 trailing arbutus, 433—434 

 (See also Growth substances) 

 Propagation of plants (vegetative) : effects of growth 



substances, 211-215 

 Propane: injury to plants, 179-lSO 

 Propylene: effects on roots, 173 



physiological effects on plants, 142-143, 152, 163 

 Prunus, 14, 91 

 Prunus americana, 92, 130 

 Pseudayitltus, 30 

 Psoralea, 30 

 Ptelea, 91 



Puccinia antirrhini: effect of sulphuric acid and 

 hydrogen sulphide on germination of spores, 

 3(33-360 

 use in greenhouse tests of fungicides, 379 

 Pultenaea, 30 



Pyrethrin I : improvement in method of determina- 

 tion, 350 

 Pyrethrin I and II: relative toxicity to insects, 350- 



351 

 Pyrethrum: effects on muscles, nerves of houseflies, 

 348-350 

 toxicity, 346-351 



toxicity to Tenebrio molitor, 346-347 

 Pyrus, 91, 419 



Quality of radiation effects: study of plants grown 

 under glasses transmitting light of various 

 ranges of wave lengths, 313-320 



Radiant energy: (See Infra-red effects) 



Radiation: amount per acre, 286-287 



Radiation and water loss of plants: (See Transpira- 

 tion) 



Radiation effects: on plant growth, 285-390 



Radiation, solar: required for plant growth, 286 



Ranunculus, 75, 70 



Red spider: (See Tetranychus bimaculatus; Tetramj- 

 chus telarius) 



