MORPHOLOGY OF THE BARLEY GRAHsT. 11 



Puriewitsch ^ concedes no more power to the aleurone layer than to 

 the rest of the endosperm. 



Torrey,^ m studies of germmatmg maize, attributes the secretion 

 of both cytase and diastase to the epithehal layer. He associates 

 the enzym with the production of a definite granular substance in 

 the epithelial cells the formation of which is coincident with the first 

 attack upon the endosperm cells. Incidentally, he attributes the de- 

 pleted layer of cruslied cells, which is formed in the later stages of 

 growth, to pressure and not to the absorption of the still growing 

 endosperm by the expanding scutellum. 



Van Tieghem ^ finds, among many things less pertinent to this dis- 

 cussion, that the embryo of Mirahilis jalapa is capable of utilizing 

 macerated endosperm as a nutritive substance. 



Sachs ^ considers, except for minor details, that the relation of 

 embryo to endosperm is one of parasite to host. 



Lmz ■' finds that the removal of the aleurone layer of corn makes 

 httle difference in the dissolution of the endosperm. He concludes 

 that this layer is not secretive. 



Grtiss*^ finds that the scutellum of barley is able to secrete abundant 

 diastase and to nourish itself upon starch supplied in place of the 

 endosperm. 



Reed ^ looks upon the epithehal layer as containing the only 

 secreting cells in either Zea mays or Phoenix dactylifera, but concerns 

 himself mostly with the changes in nuclear and plasmic conditions. 



BroMTi and Escombe ^ conclude that the scutellum of barley secretes 

 diastase, but that the production of cytase occurs in the aleurone layer, 

 but they donot find anypowerof secretion in a detached aleurone layer. 



Green ^ assigns the origin of cytase for the most part to the aleurone 

 layer, but attributes the production of the greater part of the diastase 

 t() the scutellum. 



Brown and Morris,'" in oiie of the most exhaustive investigations 

 to which these questions have been subjected, find the scutellum of 



' Puriowitsch, K. Physiologische Untersuchimgen iiber die Entleerung dcr Resorvcstoffbehiiltcr. 

 Jahrbijcherfijr Wi.ssenschaftliehe Botanik [I'ringshclm], Bd. 31, Ileft 1, p. 1-76, 18i)7. 



«Torrey, J. C. Cytological changes accompanying the secretion of di:isl:ise. iUilletin, 'rorrt'y Bolaii- 

 ical Cluh, V. 29, no. 7, p. \2l-\:>,r,, pi. 20, i;)02. 



' Van Tieghem, f. K. L. Ilecherches physiologiqucs siir la goriniiKil i(jii. Amialcs dcs S(a('iic(vs Nutu- 

 rellcs, BoUinique,s. 5, t. 17, p. 20.>-224, 1873. 



« Sa<;h.s, Julius von. Lectures on the Physiology of Plants. 'I'r. liy II. M;iisliiill Ward, o.xfoid, lss7, 

 p. .373. 



-lAm, Y. Beitriige zur Physiologie dcr Keimung von Z('a mais. .Iiilirhiirlin- fiir Wisscnsciiiifliichd 

 Botanik I Pringsheim], Bd. 20, Heft 2, p. 318, 1896. 



'GrlLis.J. Ueber die .Secretion desSchildchens. Jahrl.iirliiTfiir \VissiMiscli:iflliclic I'.ohniikl riin)_'slicini|, 

 Bd. 3f), Heft 1, p. BLV-fifil, 1 fig., 1807. 



' Heed, II. S. .Study of the enzym-secreting cells In iIh' :.i'C(llirif.'s ciT /ciuiiais miM i'lKH'iiix daily liliTa. 

 AnnaLs of Botany, v. 18, no. 70, p. 267-287, pi. 20, 100). 



' Brown, II. 'I'., and Ks<;oml)e, I". f)n the dcjdoiioii of lluM^Tido.sinTin ol lldrdciini vnlcariMliii ini; ^^criiii- 

 natiori. Prweedings, Royal Sodely, Kori'lon, v. 63, no. 3H'l, ]>. 3 2:,, pi. I , l.s:.s. 



' firr-en, J. U. Holnble FermcntH and Fenrientatlon. Cambridge (i;ngland|, 181)11, p. 20, o.',. 



''' Brown, 11. T., and .Morrl.<, 'i. M, Henearclies on the gemilnaMon of some of tlio (iraiiiincn', |iir(, 1. 

 Journal, Chemical Hociety [London), v. .17 (Traasttcllon.s;, p. 458-528, 1800. 



