l602 AGRICUI<TURAL BOTANY, CHEMISTRY AND PHYSIOLOGY OF PLANTS 



experiment very little, if any, depletion of soil moisture took place below 

 the depth of root penetration. 



The average leaf areas of five representative plants of corn Blackhull 

 Kafir and Dwarf ]\Iilo were obtained at stages when the plants were 4, 

 6, 8 and 10 weeks of age. The last stage examined showed that the plants 

 had completed their full leaf development. In all the stages of growth 

 the com plant was found to have the greatest leaf area. Taking the 

 stages of gro\vth in order, the leaf area of the corn plant was 1.7, 2.0, 

 2.2 and 2.3 times the leaf area of Dwarf Milo and 1.6, 1.9, 1.5 and 1.5 

 times of that Blackhull Kafir. 



From the experimental results it is apparent that the Dwarf ]\Iilo and 

 Blackhull Kafir plants would have the advantage over the com plant 

 under any climatic conditions that would tend to bring about a loss of 

 water from these plants. The two sorghums have, in the first place, as 

 compared to the corn plant, only one-half the leaf surface exposed for the 

 evaporation of water ; and in the second place they have a root sj'stem 

 which, judging from the number of secondary roots, would be twice as 

 efiicient in the absorption of water from the soil. 



1171 - Barium in Tobacco and Other Plants. — artis b., and maxwell h.i,., in Chemical 



News, Vol. 114, No. 2059, pp. 62-63. London, August nth 1916. 

 Other workers (i) have found barium in various plants and, as this 

 element is widely distributed in soils, the question has arisen as to whe- 

 ther it is really a plant food, although it has not been foimd in all the spe- 

 cies anah'sed. The writers of this article have examined the leaves and 

 stems of tobacco grown in various places and also the leaves of several 

 other plants, some of which were grown on soils containg 0.1312 per cent 

 of barium sulphate. The chief results are summed up in the appended 

 Table. 



Table I. — Proportion of barium in tobacco groum in different places. 



Havana tobacco from Cuba 



Broad leaf, grown in Pennsylvania .... 

 Havana seed grown in Connecticut .... 

 Pennsylvania tobacco, grown in Pennsylvania 



Sumatra tobacco 



Winconsin tobacco, grown in Wisconsin . . 

 Tobacco grown in New York State. . . . 



20.S5 

 21.98 

 20.11 

 21. 48 

 20.87 

 21.62 



0,0608 

 0.0648 

 0.0600 

 0.0980 

 0.0308 

 0.0192 

 0.0132 



25.68 

 21.62 

 19.38 



24-73 

 24.49 



0.0760 

 0.0780 

 0.0720 



24.28 ! 0.1280 



0.0408 

 0.0280 

 0.5040 



(i) See B. .\ugust 1913, No. 924. 



(Ed.) 



