454 



SUBJECT INDEX 



Growth substances effects — continued 



on plants under varying light conditions, 205-208 

 on preharvest apple drop, 215 

 on seeds, 418-420 



Halesia: effects of illuminating gas on roots, 173 

 Halesia Carolina, 112 



Half-leaf method of studying changes in leaves, 409 

 Halicijstis: formation of the cellulose particles, 273- 



2S2 

 Halicyslis osterhoutii, 273 

 Halicystis ovalis, 273 

 Hamamelis 90 

 Hardenbergia, 30 



Helianthus cucumerif alius, 316, 332 

 Helianthus tuberosus: as affected by growth sub- 

 stances, 212 

 Heptane: injury to plants, 179-180 

 Hermannia, 30 

 Herpetomonas hancrofti, 14 

 Hevea, 33 



Hexane: injury to plants, 179-180 

 Hibiscus, 30, 35, 148, 149 

 Ilippeastrurn, 14 

 Holly leaf miner: control, 357 



(See also Phytomyza ilicicola) 

 Hormones: {See Growth substances) 

 Hormones, natural: produced by gravity and shad- 

 ing, 220 

 Houseflies: (See Musca domestica) 

 Hovea, 29, 30 



Humidity effects on: moisture content of seeds, 

 53-55 



stored pollen, 429-430 

 H^■l)ridization: bigenerio gladiolus, 430-431 



Liliuni, 430 



new fragrant gladiolus, 430-43 1 

 Hydrangea, 78 

 Hydrangea macrophylla: acidity of soil, aluminum, 



iron effects on color, 423-424 

 Hydrocyanic acid in illuminating gas: toxicity to 



plants, 175-178 

 Hydrogen cyanide gas: effects on plants and ani- 

 mals, 197-200 

 Hydrogen sulphide: effects on plants and animals, 

 197-200 



injury to plants, 179-lSO, 193-194 



role in fungicidal action of sulphur, 363-366 



toxicity to fungus spores, 363-366 

 Hydroids: on aquatic plants, 20-21 

 Hypericum, 34, 42 



Hypodermis of insects: effects of insecticides, 348- 

 350 



Ilex: as affected by growth substances, 213 



Illuminating gas: (See Ethylene) 



Impatiens, 90, 126 



Impatiens balsamina: dormancy and germination in 



seeds, 123-126 

 dry storage effects, 123-125 

 Indigofera, 30, 31 

 /3-Indoleaeetic acid effects: on germination of seeds, 



418-419 

 on plants, 206-215 

 /3-Indolebutyric acid, 218 

 |3-Indolebutyric acid effects: on germination of 



seeds, 418-419 

 on plants, 200-215 

 Indolepropionic acid: effects on plants, 206-21 o 

 Infra-red effects: on transpiration in plants, 328- 



330 

 Inhibition of growth: (See Growth inhibition) 

 Insect vectors: of yellows diseases, 10-15 

 Insecticides: ^./S'-dichloroethyl ether fumigation, 



356-357 

 effects of wetting agents on efficiency, 357 



effects on nerves and muscles of houseflies, 348- 



350 

 factors affecting efficiency and mode of action of 



contact insecticides, 343-352 

 research on synthetic products for, 354 

 survey of plant products for, 354 

 thiocyanogen compounds, 351 

 Insecticides, contact: fatty acids and soaps, 344-346 



studies, 343-359 

 2-Iodobenzoic acid, 223 

 3-Iodobenzoic acid, 223 

 4-Iodobenzoic acid, 223 

 Ipomoea, 30, 35 

 Iris, 90 

 Iris, Japanese: carbon dioxide effects on flower 



color, 403 

 Isoelectric point: acidification of salt solutions in 

 relation to plant tissue isoelectric points, 

 416-418 

 concerning the determination of the isoelectric 

 point of protoplasm, 414-418 



Jacksonia, 30 



Japanese beetle: (See Popillia japonica) 



Jasione, 42 



Juglans, 90 



Juncus, 34 



Junipfrrus, 89, 90, 92, 97, 98 



Kalanchoe: responses to growth substances, 211 

 Kennedya, 30 



L/ahurnum, 51 

 Lactuca, 77 



Lactuca sativa: carbon dioxide effects on dormancy, 

 399-400 



dormancy and germination in seeds, 125 

 Lathyrus, 73 

 Lavatera, 29 

 Leafhopper: (See Cicadula sexnolata; Macropsis 



trimaculata) 

 Leaves: changes during night, 410-412 



changes in nitrogen, 410-411 



changes in residual dry weight, 410-411 



chemical changes during period preceding frost, 

 412-414 



diurnal changes, 408-412 



effect of transpiration on, 329 



half-leaf method of studying changes in, 409 



twin-leaf method of studying changes in, 408-414 

 Length of day: (See Photoperiodism) 

 Lepidium, 36, 37, 38 

 Leptospermum, 33 

 Lesvedeza, 35, 72, 73 

 Lettuce : (See Lactuca sativa) 

 Leucaena, 29 

 Lewisia rediviva: dormancy and germination of 



seeds, 127 

 Libocedrus, 90 



Life span of seeds: (See Seeds; life span) 

 Life span of seeds in dry storage, 39-40 

 Life span of seeds in soil: 33-41 



factors affecting, 38-39 

 Light duration: effects on plants, 304-309 

 Light effects: as related to growth substances, 205 



on chlorophyll pigments, 330-331 



on flowering of Digitalis purpurea, 334-337 



on plant anatomy, 331-333 



on plant microchemistry, 331-333 



on plants' response to growth promoting sub- 

 stances, 225 



on seed germination, 74-78, 123 



on transpiration in tobacco, 328-330 

 Light effects on plants: constant-condition rooms 

 for study, 286-290 



