1921] HOWE—ROOT HAIRS 319 
may help change some of the difficultly soluble salts, such as 
tricalcium phosphate, to a soluble form that can be used by the 
plant. 
TABLE IITI* 
SEEDLINGS GROWN IN KNop’s SOLUTION 
AMMONIUM OXALATE| RUTHENIAN RED FOR PECTIC 
AND CALCIUM PEC- MATERIAL, IN GENERAL} 
TATE FORM 2 PER CENT HYDROCHLORIC 
CALCIUM OXALA ACID FOR CHANGE OF PEC- greening 
CRYSTALS AND TOSE; 2 PER CENT POTAS- 
SEEDS AMMONIUM SIUM HYDROXIDE FOR 
PECTATE PECTIC ACID 
Test for calcium Test for pectic material Test for callose 
: oxalate crystals 
Cabbage (Early Jersey 
Wakefield) . 
Many crystals | Thick layer all around;} Thick layer; 
pectose changed thicker at tip 
e 
Seem (Early for- | Few crystals Thick layer; pectose| Very thick layer 
Re) eS, oes changed to pectic acid| all round 
bi to pectin at 
Radish (Sparkler)... ... Many crystals Pertais changed to pec-} Thick layer, es- 
tic _ - td to pec-|_ pecially at tip 
tin 
Muskmelon (Rockyford)| Few crystals Pectose changed largely — thick 
o pectin yer 
* Cellulose was not found in any of the root hairs. 
TABLE IV 
SEEDLINGS GROWN IN KNOopP’S SOLUTION 
Actpity, Pu VALUE BY USE OF CLARK 
AND LuBs’ INDICATORS 
SEEDS 
Root hairs Solution 
CADbNRE cs a ee 6.8-6.0 7-0-7 .2 
MCUMDEr. oe 7.2-6.8 8.4-7.6 
atigh oo oe 6.8-6.0 8.4-7.6 
Muskmelon. 53065 sc 6.8-6.0 6.8-6.0 
Summary 
t. No cellulose was found in the root hairs of the species studied. 
2. The root hairs grown in both loam and sand have a layer of 
pectic material on the outside, and within a layer of callose, thicker 
in some plants than in others, and usually a little thicker at the 
tips. 
