206 
Journal of Agricultural Research 
Vol. XXIII, No. 3 
than in Johnson grass. The composition of the inner integument was 
quite different in the two kinds of caryopsis. In Sudan grass caryopses 
it consisted mainly of hemicellulose, the inner walls being somewhat, 
and the outer walls rather more impregnated with suberin. In Johnson 
grass caryopses, on the contrary, the outer walls contained cellulose and 
were somewhat suberized, while the inner walls as well as the closing 
tissue were suberin, strongly impregnated with fatty substance. The 
amount of fat, both in the walls and in the cell contents, was much 
greater in Johnson grass than in Sudan grass. 
In addition to the data shown in Table II, all layers of the pericarp 
and the integument contained tannin in both kinds of caryopsis, but 
more in Johnson grass than in Sudan grass. 
Table II .—Composition of coat structures of Johnson grass and Sudan grass caryopses 
Composition. 
Part examined. 
Aleurone layer. 
Inner integument.. 
Pericarp... 
' ‘Closing tissue' * of 
the hilar orifice. 
Johnson grass caryopses. 
Cells walls hemicellulose. 
Inner cell walls pure suberin, 
impregnated with fatty sub¬ 
stances; fat also in cell con¬ 
tents. 
Outer cell walls have very 
little suberin; some cellu¬ 
lose. 
(All cell layers contain pectic 
substances and are suberized; 
a little calcium; a little cel¬ 
lulose; iron in outer layer. 
I All layers swell in 2 per cent 
oxalic acid and in ammo¬ 
nium hydrate of one-tenth 
commercial strength. 
Suberin and considerable oil, 
which comes out after 10 to 
15 minutes’ warming in al¬ 
cohol. 
Sudan grass caryopses. 
Cell walls hemicellulose. 
Inner cell walls hemicellulose, 
somewhat suberized; much 
less fat than in Johnson grass. 
Outer cell walls hemicellulose, 
more suberized than inner 
cell walls. 
Similar to Johnson grass but 
less suberized, with pectic 
substances much more abun¬ 
dant; no iron. 
Swell much more than Johnson 
grass in oxalic acid and am¬ 
monium hydrate solutions. 
Not determined. 
COMPARATIVE RATES OF BLEACHING WITH JAVELLE WATER—CORRELATION WITH 
GERMINATION 
These tests were made with one lot of Sudan grass caryopses and two 
lots of Johnson grass caryopses, using only uninjured caryopses which 
had been removed from the scales by hand. The Johnson grass seed 
was nearly two years old and was therefore fully after-ripened. When 
fresh, No. 37001 was an unusually ready germinator, but the San Antonio 
lot was exceptionally resistant to germination. Almost 30 per cent of 
the naked caryopses of the former and less than 5 per cent of those of 
the latter germinated in 10 days at 25 0 C. At other temperatures the 
comparison was similar. The caryopses were placed in small vials, and 
several times their volume of Javelle water was added. The Javelle 
water was renewed after 1, 2, 6, and 24 hours and at intervals of 24 
hours thereafter until bleaching was complete. The first visible effect of 
the Javelle water was a pronounced darkening of the caryopses, probably 
due either to the action of the free alkali in the solution or to oxidations. 
