1917] AGBICULTURAL BOTANY. 631 



life Wstory. A brief description is also given of a mycorrhizal fungus said to 

 enter into association witli roots of Danaia. 



The chemical conditions for the development of reproductive org-ans in 

 yeasts, I\:. Saxto (Jour. Col. Sci. Imp. Univ. Tokyo, S9 {1916), Art. 3, pp. US).— 

 The author has made a study of the Influences beaiing upon the production of 

 the organs of reproduction in Zygosaccharomyces mandshurictti, Schizosaccha- 

 romyces octosporus, and Saccharomyces mandshuricus. He states that though 

 these resemble other fungi in that reproduction stands in close relation to the 

 quantity and quality of the chemical substances available, reproduction depends 

 else, in case of certain organisms, upon the presence of specific chemical sub- 

 stances. Several such requirements are indicated. Among the significant 

 physical considerations, osmotic activity plays an important rOle in determining 

 concentrations and consequent development of reproductive parts. The factors, 

 both internal and external, are thought to be very numerous, and together to 

 constitute a very complex mechanism. 



Microchemical studies in the progressive development of the wheat plant, 

 Sophia H. Eckerson {WasMngton Sta. Bui. 139 (1917), pp. S-21, figs. 13).— 

 The author states that the progressive chemical changes during the develop- 

 ment of the wheat grain are correlated with morphological changes, each defi- 

 nite period of the morphological development being characterized by some 

 chemical difference. The progre.ssion of these chemical changes was found to 

 be alike In all varieties tested of both winter and spring wheat. 



Summarizing her results, the details of which are given, the author reports 

 that inorganic materials are high in the young plant. The largest amount 

 of potassium nitrate was found, chielly in the root and stem, just before the 

 formation of the spike, after which it decreased gi-adually. Free magnesium 

 quickly fell to a minimum during the formation of the aleurone, while free 

 phosphate rose to a maximum during development of the sporogenous tissue, 

 falling to a minimum after the development of the sex cells. 



Asparagin is thought to be a very important nutritive substance, and it was 

 found together with fructose in all young growing parts. The occurrence of 

 pectic substances on the stigma Is considered especially important in reducing 

 the rate of water absorption by pollen grains. During the period from the 

 fertilization of the egg to the mature grain, there is said to be a stream of 

 nutrient materials for the growing embryo coming to the endosperm from the 

 leaves and glumes. Any excess of sugar was found to condense Immediately 

 into starch. Excess of asparagin and amino acids remained as such in the 

 endosperm cells until desiccation of the grain. The nitrogenous compounds in 

 the endosperm just before ripening of the grain, aside from aleurone and proto- 

 plasm, are asparagin, arginin, hlstidin, and some leucin. No glutamin was 

 found. 



Protein, which has the physical characteristics of gluten, is said to appear 

 in the storage cells on desiccation of the grain, the amino acids and most of the 

 asparagin disappearing. The formation of the storage protein in wheat is be- 

 lieved to be a condensation process. 



The physiolo^cal role of calcium in veg^etable life, THfeaisK Robebt {Rev. 

 Q&n. Sci., 28 {1917), No. 4, pp. 101-108).— The author discusses the ability of 

 plants to utilize calcium in their economy, as deduced from the examination 

 of a very large number of Investigations by various authors, taking up more 

 particularly the relation of calcium to phanerogams. Including the distri- 

 bution of calcium in Its various forms In the plant body ; its necessity, or at 

 least utility, in relation thereto ; its mode of action or rCle as plastic, catalytic, 

 toxic, or antitoxic ; and its replacement or substitution by other elements. 



