430 Journal of Agricultural Research voi. xiii, no. s 



This was before his discovery of quercimeritrin. Gossypol is evidently 

 a somewhat unstable substance; Withers and Carruth (jp) state that it 

 readily forms an oxidation product which is physiologically inert. Its 

 nature is also evidently changed by moist heat. Osborne and Mendel (8) 

 find boiled cottonseed kernels to be nontoxic. The investigations of the 

 present writers show that it is not formed, or if formed as a preliminary 

 step in the synthesis of the quercetin glucosids, is immediately changed 

 in those tissues which are exposed to the action of normal daylight. As 

 gossypol occurs in the glands of the flower before opening and querci- 

 meritrin after opening, the former apparently in this case gives rise to the 

 latter; but the exact nature of the change remains uncertain. This 

 change of gossypol differs from that in the unfolding of the cotyledons. 

 Here no quercimeritrin seems to be produced, the gland content giving 

 a greenish-brown emulsion with sulphuric acid. 



RELATIONSHIP BETWEEN THE FLAVONES AND THE ANTHOCYANS 



A definite relationship between the flavone glucosids and the antho- 

 cyans is assumed by Perkin (//) in citing the experiments of Everest (j), 

 who formed anthocyans by a reduction of certain glucosids. The con- 

 stant association of the two in the glands exposed to light, their immediate 

 formation in those of the corolla as the petals unfold, and in the full- 

 blown flower, the development of anthocyans in cells previously contain- 

 ing flavones and still containing them, point to a photochemical process 

 resulting in the development of anthocyans from the glucosid. It is 

 not asserted, however, that the development of anthocyan is here neces- 

 sarily dependent on the preformation of glucosid in demonstrable quan- 

 tities ; anthocyan is frequently developed in the epidermal cells of stems, 

 petioles, and leaves under extreme insolation where no flavone can be 

 demonstrated. The stimulus of light, to which the development of 

 anthocyan in normal tissue is here conjecturally referred, seems not to 

 be invariably necessary. In the interior of certain bolls what appeared 

 to be an abortive second boll developed, and in the outer tissues of this 

 were developed glands analogous to those of normal tissue, containing 

 no gossypol, but with pronounced anthocyan-bearing envelopes, although 

 the stimulus of light was insufficient for the development of chlorophyll 

 in the surrounding tissues. 



POSSIBLE BIOLOGICAL SIGNIFICANCE OF THE INTERNAL GLANDS 



Whether or not the substances found in the glands are of definite use 

 to the plant is an unsettled question. Many investigators, notably 

 Haberlandt {4 p. 526) have regarded the contents of glands of this 

 general type as excretion products useless to the plant, basing this con- 

 clusion largely on the fact that they remain thus localized indefinitely 

 without change. The change of gossypol upon the unfolding of the coty- 

 ledon may indicate its usefulnesss in the metabolism of the young seedling. 



