IIOO AGRICUl/rUKAL 150TAXY, ClIKMISTRY AND rilVSIOLOGY OF PLANTS 



acid gas is formed, which gives lise in the leaves to the formation of starch 

 as a consequence of the chlorophyllian function. 



The glucose absorbed is readily oxidised in the plant. This also agrees 

 with the experiments of Mollia.rd {Comptes Rendus dc V Academic des Scien- 

 ces, 141, 389-1905), who, in plants treated with glucose, found a greater 

 degree of acidity, which is a sign of the incomplete oxidation of the sugar. 



The investigations will be continued, chiefly with substances of the aro- 

 matic series, which are also presumed to be energetically oxidised by plants. 



854 - The Influence of Boron on Plant Growth. — i. voelckbr j. a. [TheWoburn 



E.Kperiinental Station of the Royal .\.gricultural Society of England, Pot-Culture Expe- 

 riments, 1915, ip) The influence of Boron Compounds, on i) Wheat, 2) Barley], in The 

 Journal of the Royal Agricultural Society of England, Vol. LXXVI, pp. 347-351 -r pi. 3-4. 

 lyondon, 1913. — -II. Cook F.C. (Physiological Chemist, Bureau of Chemistry, U. S. Dcpt. 

 of Agric). Journal of Ar;ricultural Research, Vol. V, No. 19, pp. 877-890. Washington, 

 D. C, 1916. 



I. — Duplicate pot-experimeiits with boric acid and borax upon wheat 

 and barley ; the quantities of the boron compounds used were from o.oooi 

 to o.io per cent, of the element as reckoned on the whole content of each 

 pot. 



On considering the results obtained the following conclusions may be 

 drawn : 



1. Germination is retarded when anything over 0.003 per cent, of 

 boron is used, and even o.ooi per cent., more especially with borax, seems 

 to delay germination. 



2. Anything over o.ooi per cent, of boron, either as boric acid or borax, 

 will prevent plants from developing and forming grain. 



3. A toxic influence is shown with 0,0005 per cent, of boron, but with 

 quantities not exceeding 0.00025 P^r cent, there is a slightly stimulating 

 effect. 



4. The effects generally are more marked with borax than with 

 boric acid. 



II. — - The experiments repoited were made in connection with a 

 cooperative study of borax and calcined colemanite (i) as larvicides for 

 the house fly (2) condiicted by the Bureaux of Entomology, Chemistry, and 

 Plant Industry, of the U. S. Department of Agriculture. The object of the 

 present paper was to determine the effect of boron-treated horse manure 

 on plant growth, and to study the absorption of boron and its distribution 

 in the roots, stems and fruit of plants grown on soil fertilized with this ma- 

 nure and on soil fertilized with untreated manure. The plants (wheat, 

 beets, tomatoes, cowpeas, lettuce, soybeans, potatoes, corn, oats, radishes, 

 string beans) were grown in pots in the greenhouses of the Department and 

 on open plots at Arlington Experimental Farm, Va ; Dallas, Tex. ; Orlando, 

 Fla. ; and New Orleans, I/a. At least four pots for each treatment were 

 employed in the pot tests ; the plots at Arlington were ^/go of an acre and 

 the others about 7i;o of an acre; the tests with lettuce were carried out on 



(i) HN'drous borate of calcium. Cfr. Dana's Maniialol Mineraloi^y, 13th. ed., 1912. {Ed.). 

 (2) See B. 1915, Nos. 64 and 117. 



