90 



BOTANICAL GAZETTE 



[FEBRUARY 



saturated and half -saturated solutions of cumarin. Our results show 

 that cumarin is extremely poisonous to wheat plants. At the end of 

 five days the plants in 250 ppm. and stronger were dying, the roots 

 and tops having made practically no growth. The root tips were 

 swollen and slightly discolored, although the roots themselves were 

 quite turgid. Whtn the experiment was discontinued at the end of 

 eight days the plants in the solutions of 100 ppm. were dead, although 



/ 



^ I 



1.*", 



■h 



1 



■6 





>' 



^ 



5 



^ 



■^ 



'-^. 



r ^ i^■^^^^ \ l 



..:; ^?^^.v .'■ 



^ 



^-. 



■,■.,'■-^^^^''^^^^■■ 



J^-J 



■-:T.; 



-''^.. ^'V. 



■^X-. 



■_— "/ 









'X 



•. - 



L _ 

 1 \ 



.■.'.■^.; 



<'jj 



^3^..'^^ 



^^^..^ 



^Vv=- 



7^n 



■1-|->-^ FJ-O-^r-- 





T V- 



-^ - ^ 



■. ^ L h J 



Fig. 6 



■^ 







I- ^ 



-■■■.■:■■• .iAf* 



':*^ ' ^^. 



'?. 





^-^ 



■'.^J 



-'l v7^^T^^^^^«^ 



^;:^/-yiY.ia:i^ 





The 



ginning of the experiment 



their surface was very slimy, due to the death of the outer layers of 



The 



plants were short and broad, a feature not brought out by the illus- 

 trations, but which was very characteristic in all experiments with 

 cumarin. The meristematic tissue of the stem appeared to be injured 

 in such a way that only the first leaves were unfolded, and in most 

 cases the sheathing leaf base was more or less swollen by the abnormal 



inhibited 



The 



^ \. 



he solutions of 50 ppm. were alive at the end of 



