Contents 



the red, far-red reversible system 34 

 the red, far-red system in 



photoperiodism 35 

 nature and function of the red, far-red 



PIGMENT 39 



PROLONGED EXPOSURES TO LIGHT OF 

 DIFFERENT COLORS 40 



B. Time relations and endogenous rhythms 

 in photoperiodism 42 



ENDOGENOUS C1RCADIAN RHYTHMS IN 



PLANTS 44 



ENDOGENOUS CIRCADIAN RHYTHMS AS THE 



BASIS OF PHOTOPERIODISM 46 



CIRCADIAN RHYTHMS AND THE ACTION OF 



LIGHT-BREAKS 47 



FLOWERING IN LIGHT-DARK CYCLES OF 



DIFFERENT LENGTHS; TEMPERATURE 



INTERACTIONS 5 1 



ENDOGENOUS CIRCADIAN RHYTHMS AND 



THE RED, FAR-RED SYSTEM 52 



CONCLUDING REMARKS ON CIRCADIAN 



RHYTHMS AND PHOTOPERIODISM 52 



chapter four ► Temperature and Flowering 54 



vernalization: cold treatments and 

 flowering 54 



Vernalization in winter rye Vernalization 



in other plants 



DEVERNALIZATION 59 



RELATIONS BETWEEN VERNALIZATION AND 



PHOTOPERIODISM 61 



THE SEMANTICS OF VERNALIZATION! 



FURTHER EFFECTS OF TEMPERATURE ON 



FLOWERING 62 



TEMPERATURE AND FLOWERING IN BULB 



PLANTS 64 



