EMPIRICAL PLANT SPECTRA 



687 



100 



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UJ 



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 li. 

 tlJ 

 a. 



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o 



in 



(/) 



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400 



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500 600 



WAVE LENGTH, m,i 



Fig. 22.12. Transmission (Jg), reflection {Rg) and absorption (A^,) of light by 

 a green leaf of Pelargonium zonale, and the corresponding constants for a white 

 leaf (index w) (after Se.ybold 1933). The figure indicates considerable absorp- 

 tion by "white" leaves, particularly in the blue- violet region. For other absorp- 

 tion curves of "white" leaves, see Seybold and Weissweiler (19430. 



4.4 



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 o 



4.01—1 



400 450 500 550 600 

 WAVE LENGTH, m^ 



650 



Fig. 22.13. Transmission spectrum (log Ta/T) of leaves of Fatsia and Acuba 

 (after Meyer 1939). Absolute values of ordinates adjusted to give best agreement 

 with spectrum of extracted pigments. 



against wave length). One may measure /, T and R {or S = T -{- R), 

 plot T/I, R/I, or A/I (= [/ - (T + R)]/I = [I - S]/I) against wave 

 length, X, and call the resulting curves "transmission spectra," "reflection 



