CHLOROPHYLLS OF THE ALGAE 405 



On the other hand, Noack and Kiessling (1929, 1930, 1931) and 

 Scharfnagel (1931), among others, thought that protochlorophyll is con- 

 verted by illumination into chlorophyll. If this is correct, the last stage 

 of chlorophyll formation is a reduction rather than an oxidation — which 

 is possible in itself, but incompatible with the Preisser-Lubimenko theory. 



The existence of "leucophyll" and "chlorophyllogen," included in 

 the scheme of Lubimenko and Monteverde, is a matter of speculation. 

 The whole problem of chlorophyll development in seedlings certainly is 

 in need of renewed analytical study. 



3. The Chlorophylls of the Algae 



It was mentioned above that green algae behave as extreme shadow 

 plants, with an exceptionally large proportion of chlorophyll 6 (c/. 

 Table 15.11, page 410). "Colored" algae normally live in much deeper 

 water than the green algae, and could thus be expected to contain even 

 more chlorophyll h. Instead, no chlorophyll h is found in them at all. 

 Willstatter and Page (1914) left the possibility open that hrown algae 

 may contain a little (less than 5%) of chlorophyll 6; but Fischer and 

 Breitner (1936), Seybold and Egle (1938), Montfort (1940), Seybold, 

 Egle and Hlilsbruch (1941) and Strain and Manning (1942^ lowered this 

 limit to less than 1%. They also extended the experimental proof of 

 the absence of chlorophyll h to diatoms, red algae and blue algae. Pace 

 (1941) asserted recently that diatoms may contain up to 10% of the h 

 component, but Strain and Manning (19420 attributed his results to a 

 confusion with chlorofucin or "chlorophyll c," whose existence will be 

 discussed further below. The deficiency of chlorophyll h is easily shown, 

 according to Wilschke (1914) and Dhere and Fontaine (1931), by the 

 absence of its band in the fluorescence spectrum of brown algae (c/. 

 Vol. II, Chapter 24). 



Seybold and Egle (1937), Montfort (1940) and Seybold, Egle, and 

 Hlilsbruch (1941) found that the fresh- water alga, Vaucheria, although 

 green, also contains no chlorophyll h at all. Seybold and coworkers 

 saw in this an argument in favor of reclassification of this alga (as a 

 Heteroconta rather than Chlorophycea) ; they suggested that all Hetero- 

 contae may be devoid of chlorophyll h. The same authors found that 

 some Flagellatae (e. g., Volvox and Chlamydomonas) contain components 

 a and b in normal proportions, while others (e. g., Euglena viridis) contain 

 only a very small amount (< 3%) of chlorophyll b, or none at all (e. g., 

 Peridinium tabulatum) . 



Seybold, Egle, and Hulsbruch suggested that plants may be divided 

 into two large classes: "a plants" and "a + 6 plants." The division 

 may have first occurred at the level of the Flagellatae, since some of 



