. Carotenoids, their comparative biochemistry. Carotenoids. FUNCTION OF CAROTENOIDS IN PHANEROGAMS to this problem is the recent finding of Bandurski and Galston * •* * that an albino mutant of Zea mais, which contains no carotene but normal amounts of riboflavin, responds phototropically almost as well as the normal strain. For a full and stimulating discussion of this problem the reader is referred to a recent article by Galston. ^ <* ^ 12. 120 100 400 420 440 460 Wavelength (mfj.) 4-30 500 Fig. 16.—Showing the similarity between the absorption spectrum of the caro- tenoids extracted from
. Carotenoids, their comparative biochemistry. Carotenoids. FUNCTION OF CAROTENOIDS IN PHANEROGAMS to this problem is the recent finding of Bandurski and Galston * •* * that an albino mutant of Zea mais, which contains no carotene but normal amounts of riboflavin, responds phototropically almost as well as the normal strain. For a full and stimulating discussion of this problem the reader is referred to a recent article by Galston. ^ <* ^ 12. 120 100 400 420 440 460 Wavelength (mfj.) 4-30 500 Fig. 16.—Showing the similarity between the absorption spectrum of the caro- tenoids extracted from Avena seedlings and the action spectrum for the phototropic bending of these seedlings {after Johnston, £. S. (1934) Smithsonian Inst. Pub. Misc. Coll. 92, No. II., and Wald, G. (1943) Vitamins & Hormones, i, 208). Tauc 2 0« has shown that illumination of the epicotyl of Vicia faba produces a potential difference between the illuminated and non- illuminated side. The action spectrum for the photo-electric effect is very similar to the absorption spectrum of ^-carotene and this, together with the fact that the effect is most marked in the regions of carotenoid accumulation inclines Tauc to the view that carotenoids mediate in this response. CAROTENOIDS AND REPRODUCTION It will be noted in later chapters that there is considerable cir- cumstantial evidence that carotenoids have a part to play in the repro- duction of cryptogams and of various animal species ; this possibility must now be considered in the phanerogams. The whole problem of carotenoids and reproduction has recently been diacussed. ^»^. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Goodwin, T. W. (Trevor Walworth). New York, Chemical Pub. Co.
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