1918.] FIELD CROPS. 737 



large decrease in dry weight, an unhealthy appearance and lack of lateral roots, 

 and the death of the root tips. 



Seedlings were also grown in gooo Potassium hydroxid and hydrochloric 

 acid solutions and in a solution of acid potassium carbonate (500 parts per 

 million). The hydrochloric acid solution . proved fatal to the plants, while 

 neither of the others caused perceptible injury. These results led to the con- 

 clusion that such dilute solutions were not capable of showing the effect of the 

 hydroxyl ion on plant growth. The practical bearing of these studies on field 

 conditions is briefly discussed, but no definite conclusions are reached. 



Further data are presented which are held to indicate a general tendency on 

 the part of the plant to so regulate the reaction of the media that excessive 

 concentration.s of the hydrogen or hydroxyl ion can not occur. Barley seed- 

 lings grown in potassium chlorid solutions of .500 parts per million total con- 

 centration gave no evidence of injury due to excessive hydrogen-ion concentra- 

 tion through the formation of hydrochloric acid as a result of the selective 

 absorption of the potassium ion. The addition of aluminum to potassium chlorid 

 solutions in which a number of barley seedlings were grown caused injury to 

 the root tips and inhibited the formation of lateral roots. 



Inheritance of endosperm color in maise, O. E. White {Amer. Jour. Bot., 

 4 {1911), No. 7, pp. 396--i06). — The author reviews and briefly summarizes the 

 work of Lock, East (E. S. R., 22, p. 627), East and Hayes (E. S. R., 25. p. 736), 

 Burtt-Davy (E. S. R., 31. p. 331), Emerson, and Collins (E. S. R., 29, p. 34), 

 and presents new data obtained from his own studies showing the growing 

 complexity of facts and their interpretation in the heredity of endosperm color 

 in maize. 



California Golden Pop (Z 14) with yellow endosperm and a strain of white 

 endosperm maize (Z 21), known as Zea caragua (E. S. R., 11, p. 23), were 

 used as the parent strains, together with a white endosperm variety of Hopi 

 maize. The Fi progeny of Z 14XZ 2] gave uniformly white endosperm grains, 

 while similar results v.'ere secured from a cross of Z 14 with the Hopi variety. 



The Fz progeny of Z 14XZ 21 numbered 9,663 individuals, 6,999 of which were 

 classed as white and 2,664 as yellow. Assuming a one-factor difference between 

 the two races, vrith white completely dominant or nearly so, the theoretically 

 expected numbers would be 7,248 ^^' : 2,416 Y. The yellow segregates presented 

 all shades from a dark yellow (not orange) to a very light, lemon yellow on 

 the same ear, while in .some ears the yellow color was largely confined to the 

 base of the grain. 



From self-pollinated ears of the Fo generation approximately 1,000 plants 

 were grown, giving Fs endosperm seed. Of these 43 ears were self-pollinated, 

 27 coming from Fj seed classed as white and 16 from F2 seed classed as yellow. 

 Nine of the white seeds gave all white Fs progeny, while 19 gave both white 

 and yellow grains approximating a 3 W : 1 T ratio. The 16 Fi seeds classed as 

 yellow gave 14 all yellow ears and 3 ears with both white and yellow seeds, 

 in a 3 W : 1 Y ratio. The yellow and white endosperm color varied markedly 

 in this generation, due to a segregation of factors affecting the texture and 

 the degree of translucency. 



Unbagged ears of Z 14 grown in close proximity to varieties with deep yellow 

 or orange endosperm color invariably developed a larger number of dark 

 yellow or orange grains, from which a dominance of these yellows over that 

 of Z 14 is to be inferred, as baggctl ears always gave ;i uniform medium yellow. 

 Unbagged ears of Z 21 gi'own under similar conditions have never been kno^vn 



