Vol. 15—1961 - NorthEastern Weed Science Society

and top.extractions gave the results shown in Table 3•.
Table 2. Inhibition
from Green Haterial
with Dr;y Material.
of Extracts
Compared
343.
Table 3. Inhibition of Extracts
from Tops Compared with Roots.
Tt§atment
Dry Plant Haterial
Extraction
Green Plant liaterial
Extraction
~ Gemination
12
14
Treatment . %Germination
Tops 15
Roots 15
Control (Water) 100
.Control (Water) 100
There were obviously no differences between roots and tops, therefore,
both parts of the 'Plants were used for subsequent extractions.
Characterization
of Inhibitor
Heat t The effect of heat on the inhibitor (s) was checked. Autoclaving the
'To'Xtail extract for 20 minutes at 15 pounds rressure (2600F) did not affect
the inhibitory activity of the eXtract (Table 4). Similar results were
obtained by boiling the extracts.
Osmotic Pressure: A test of the possible effects of'osmotic pressure was
conducted. The osmotic ,ressure of foxtail, timothy, or orchard grass
extractions was determined by the freezing point depression method (Ta.ble 5).
Table h. The Effect of Heat
on Inhibition.
Table 5. The Effect of Osmotic Pressure
on Inhibition,
Treatment
Foxtail Extract 0
(autoclaved)
Foxtail Extract 0
(not autgclaved)
%GerminAtion
Control (Water 100
Treatment O,P,(AtlIlB,) %Germination
. 5
Timothy Filtrate 2.97 .
70
Orchard Grass
Filtrate
2.76 74
Foxatil Filtrate 2.95
Sucrose Solution 2.95 95
(O,lliO
Control (Water) 100