THE PRODUCTS OF PHOTOSYNTHESIS 



211 



TABLE 28 



The Formation and Disai'peakance ok Starch ix Lkaves of Different Plants 

 AS Determined by the Iodine Test. ( Fnun Eckerson. ) 



Disappearance 



of Starch in 



Darkness 



(18-22°) 



Name of Plant Nights and Days 



Abutilon 2 1 



Begonia coccinea 3 3 



Brassica oleracea 1 



Cineraria cruenta (young Is.) . 5 4 



Coleus blumei 2 1 



Cucurbita pepo 1 



Euphorbia pulcherrima 2 1 



Fuchsia speciosa 1 



Helianthus annuus 1 



Heliotropium peruvianum .... 1 



Impatiens sultani 1 



Lupinus albus 1 



Oxalis bowiei 1 



Pelargonium domesticum 2 1 



Pelargonium peltatum 3 3 



Pelargonium hortorum zonale. 2 1 



Phaseolus vulgaris 1 



Primula obconica (young Is.). 5 4 



Primula sinensis (young Is.) . . 4 3 



Raphanus sativus 1 



Ricinus communis 1 



Salvia involucrata 2 1 



Salvia splendens 3 2 



Senecio mikanioides 1 



Senecio petasitis 3 2 



Tropaeolum majus 2 1 



Vicia f aba 1 



Zea Mais 3 2 



Formation of 



Starch in Light 



(20-25°)- 



Perceptible 

 Figure 



Good 

 Figure 



Minutes Minutes 



30 

 60 

 20 

 45 

 30 

 15 

 60 

 45 

 30 

 45 

 30 

 60 

 45 

 50 

 50 

 20 

 20 

 120 

 45 

 35 

 20 

 90 

 30 

 20 

 30 

 50 

 60 

 30 



120 



240 



50 



180 



SO 



50 



240 



90 



120 



120 



120 



240 



240 



240 



270 



50 



90 



240 



120 



60 



60 



120 



60 



50 



180 



90 



240 



120 



Iodine 

 Test 



Minutes 



5-10 

 10 



5 

 30 



3-8 



4-15 

 20 

 15-25 



5 



5-10 



5 



3 



10-30 

 40 

 60 

 10-15 



5 



5-10 

 10 



3 



5-15 



4 



1-5 



5 

 25 



1 

 10 



5 



portion of this may remain in the leaf as starch. Thus leaves of Helianthus 

 annuus produced about 12 grams of material per square meter in 12 hours, 

 but of this amount only 1.40 gram was observed as an increase in starch in 

 the leaves. A considerable proportion of the material synthesized in a 



TABLE 29 

 Starch-content of Various Leaves at Different Times of the Day. 



