ACTION OF ALPHA-CROTONIC ACID ON PLANTS 
becomes apparent that the phosphate has lessened the toxicity of the com- 
pound. In the 21 mainly phosphatic cultures growth was reduced 26 per- 
cent, in the 21 mainly nitrogenous, 28 percent, and in the 21 mainly potassic, 
30 percent. 
Table 4 
Showing the influence of phosphate in overcoming the harmful effect of a-crotonic acid. 
Green weight of wheat plants in nutrient solutions composed of NaH2P04, 
NaNOs, and K2SO4. Cultures arranged according to content of P2O5 
Culture No. 
(See Fig. 2) 
Parts per Million of 
PvOs in Nutrient 
Solution 
Average Green \ 
Without Crotonic 
Acid 
Veight of Culture 
With 25 P.p.m. 
Crotonic Acid 
Percentage Decrease 
Due to Crotonic 
Acid 
grams 
grams 
I 
80 
1.47 
1.22 
17 
2- 3 
72 
1.86 
1-39 
25 
4- 6 
64 
2.31 
1.74 
25 
7-10 
56 
2.38 
1.82 
24 
11-15 
48 
2.47 
1.79 
27 
16-21 
40 
2.64 
1.92 
27 
22-28 
32 
2.81 
2.01 
28 
29-36 
24 
2.93 
2.18 
26 
37-45 
16 
3-07 
2.29 
25 
46-55 
8 
3.22 
2.29 
29 
56-66 
0 
2.93 
I.9I 
35 
The results with the mono-sodium phosphate are therefore similar to 
those with the monocalcium phosphate. This experiment seems to show 
that the calcium in the phosphate salt played no significant part in the 
observed action, since the same general action is produced by the mono- 
sodium phosphate. 
Effect of Di-sodium Phosphate 
In the experiment using di-sodium phosphate (Na2HP04) the wheat 
seedlings grew from May 2 to May 14, 191 7. The green weight results for 
\ 
l^^ \z'! 
228/ a26 408 526 \2^5 
* • • \ 
202/ 3A1 a^-O 238 2^7 \2.47 
/ * * • " \ 
ISa/ ^3 3,46 :^4 ^5 Xaji 
4 • • • • • y 
:JP8 335 323 3P7 '4p5 \a20 
ipy ^5 4i;L5 571 3P5 3P0 
l^y 2§3 ^5 3§4 4^ 4^9 3^3 354 310 
2i,y 2.71 310 315 \2.75 
324 328 ;^J59 518 
• • • • > ■ 
2^Z 3.76 3^7 33.8 323 \2^9 
1^^ 2i^0 2^4 3^3 4^9 3P5 ^5 N1^7 
^8 2^2 3^5 320 .3gO 3g3 3^0 \J^4 
l^y 1^6 1^8 ^2 ^5 ^3 2^6 L^6 Vp2 
2j'2 ^66 3.77 5^"8 3^7 ^7 5^9 Sj'O 2^3 ^ 43 1.2 ^ ^5 1.45 1^58 3^5 3.91 1,72 U7 1^1 2PS \j 6 
Fig. 7. Green weight in grams of wheat plants in nutrient solutions containing varying 
ratios of phosphate, nitrate, and potash, the source of P2O5 being di-sodium phosphate, 
(i) Without crotonic acid, and (2) with 25 p.p.m. crotonic acid. 
