418 University of California Publications in Agricultural Sciences [Vol. 1 



b. Worst poisoned plants; roots badly affected, tops less af- 

 fected; 3.0, 1.0, 0.8, and 0.5 cultures. (Nos. 3700, 3699.) 



Series Squash 121-66. — Grown in well water containing Cu 

 as Cu(0H),.CuC03 as follows: check, 3.0, 1.0, 0.8, 0.5, 0.3, 0.1, 

 0.08, 0.05, and 0.03 p.p.m. Cu. December 10-February 27, 1907. 

 Series divided into two portions: 



a. Least poisoned plants; roots growing; tops strong; 0.3, 0.1, 

 0.08, 0.05, and 0.03 cultures. (Nos. 3698, 3701.) 



h. Worst poisoned plants; roots dead or nearly so; tops badly 

 affected; 3.0, 1.0, 0.8, and 0.5 cultures. (Nos. 3696, 3695.) 



TABLE XI 



Copper Coxtext op Plants in Water Cultures 



Dry Cu 



matter Cu p.p.m. dry matter 



Condition of in found, , ^■- s 



No. Series sample grams grams tops roots 



3694 Corn, .1, .08, .0.5, .0.3 Tops affected 6.3 .00009 14.30 



3693 Corn, .1, .OS, .05, .03 Roots growing 2.3 .000236 102.60 



3692 Corn, 3., 1., .8, .5, .3 Tops living 4.8 .000056 11.70 



3691 Corn, 3., 1., .8, .5, .3 Roots arrested 2.8 .000572 204.30 



3702 Beans, .3, .1, .08, .05, .03 Tops normal 9.4 .000198 21.10 



3701 Beans, .3, .1, .08, .05, .03 Roots growing 2.6 .000157 60.40 



3700 Beans, 3., 1., .8, .5 Tops affected 6.6 .000204 30.90 



3699 Beans, 3., 1., .8, .5 Roots badly 



affected 1.6 .000494 308.80 



3698 Squash, .3, .1, .08, .05, .03 Tops strong 10.4 .000333 32.00 

 3697 Squash, .3, .1, .08, .05, .03 Roots nearly 



normal .6 .000087 145.00 

 3696 Squash, 3., 1., .8, .5 Tops badly 



affected 3.6 .000092 26.00 



3695 Squash, 3., 1., .8, .5 Roots dead .2 .000058 290.00 



It is noteworthy, in this series, that the amounts of copper 

 found in roots that still retain the power of growth average 

 about 103 parts in one million of dry matter, as compared with 

 268 parts in dead roots whose protoplasm is presumably killed as 

 an effect of copper. Badly poisoned roots in every instance show 

 a great excess of copper over those less affected. The tops, on 

 the other hand, do not show copper in proportion to the amounts 

 in the roots, averaging the same amount of copper in badly 

 poisoned (22.9 p.p.m.) and in slightly poisoned (22.5 p.p.m.) 

 plants. Corn was observed to be distinctly more sensitive to 

 copper in water culture than either squash or beans, as was 



