Subject Index • 163 



Lamarckism, 55 



LDP, see Long-day plants 



Leaf, age, and photoperiodic sensitiv- 

 ity, 119-120; blades, photoperiodic 

 perception by, 17; movements, and 

 endogenous circadian rhythms, 44- 

 45, 50; number, minimum, 117-118; 

 true, compared to cotyledons, 38-39, 

 119 



Light and dark periods, and endog- 

 enous circadian rhythms, 47-52; 

 lengths of, 10-11, 18-20, 22-24, 51- 

 52; and red, far-red system, 35-39; 

 roles in photoperiodism, 18-20; 

 temperature interactions with, 25- 

 27, 63-64 



Light -breaks, in action spectrum stud- 

 ies, 30-33; definition, 19; and endog- 

 enous circadian rhythms, 47-50; and 

 red, far-red system, 35-39 



Light intensity, and criteria of photo- 

 periodism, 11. 29, 131; high, re- 

 quirement for, 20-22; low, photo- 

 periodic effect of, 13, 19-20 — and 

 red, far-red system, 39 



Light quality, action spectra, 30-33, 

 52; and anthesis, 128; in main light 

 periods, 40-42; and vegetative 

 growth, 34-35, 39-40; see also Red, 

 far -red system 



Long-day plants (LDP), definition, 13; 

 and gibberellin, 91, 100-104; see also 

 Critical daylength; Light; Photo- 

 periodism 



Long-short-day plants, 13-14, 93 



Lysenkoism, 55 



Mercury, 115 



Meristem, age and flowering, 96, 120, 



124-126; organization and flowering, 



3-5 

 Molybdenum, 114 

 Monocarpic plants, 6-7 



Naphthaleneacetic acid (NAA), 97, 



107, 108, 118, 132 

 Nightlength, see Critical daylength 

 Nitrogen, see Carbohydrate, -nitrogen 



ratio; Nutrition, major element 

 N-metatolylphthalamic acid, 109 

 Nucleic acids, 92-93, 96 



Nutrition, and (lowering of daylength 

 indifferent plants, 112-113; iron and 

 trace metal, 113-115; major clement, 

 111-113. 119, 133 



Perennials, cold requirements, dever- 

 nalization, 54, 60-61; definition, 6; 

 woody, 120-126 



Phasic development, 116-117 



Phloem, see Carbohydrate, transloca- 

 tion; Plorigen, translocation 



Photomorphogenesis, 39 



Photoperiodism, classes of response. 

 13-15; criteria, definitions of, 10-11, 

 29, 131; discovery of, 11-13; effects 

 on sex expression, 131-132; effects on 

 vegetative growth, 27-28, 122-123; 

 and endogenous circadian rhythms, 

 42-53; induction by, 17-18, 83, 

 87; and leaf or plant age, 15-16, 

 117-120; and light intensity, 11, 20- 

 22, 29; and light quality, 30-33, 35- 

 39; and red, far-red system, 35-39; 

 relation to cold requirements, 61-62; 

 role of leaf in, 17, 84-87, 117-120; 

 role of light and dark periods in, 

 18-24; seasonal control by, 10-12, 

 15; temperature effects on, 25-27; in 

 woody perennials, 122-123 



Photosvnthate, see Carbohydrate 



Photosynthesis, 21-22, 29, 31-32, 41 



Photochrome, definition, 40; see also 

 Red, far-red system 



Red. far-red system, and auxin, 91; 

 and critical daylength, 37-40; effects 

 on, of light and dark periods, 35-39 

 — of light-breaks, 35-36 — of low- 

 intensity light, 39; and endogenous 

 circadian rhythms, 52; and gibberel- 

 lin, 100; nature of, 39-40; and photo- 

 morphogenesis, vegetative growth, 

 39; and seed germination, 34-35; 

 temperature effects on, 34, 36-37 



Respiration, 57, 91-92 



Rhythms, see Endogenous circadian 

 rhythms 



Ripeness to flower, see Age; Juvenility 



Rosette plants, see Bolting 



Scotophile phase, 46 



