EFFECTS OF ACID AND ALKALINE SOLUTIONS UPON PLANTS 423 
tion of water by tomato plants in alkaline solutions is less than in 
distilled water (table VIII). An exception is the KOH w/6400 solu- 
tion. The alkalies show the following order of effectiveness in which 
the kation bringing about the least inhibition is placed first: K, Na, 
Ca, NH4. As in the case of the acids, there is no relationship between 
increase in concentration of alkali and the increase in the amount of 
water absorbed and transpired. Beyond a certain optimal point a 
further increase or decrease in concentration leads to a diminished 
water relation. 
3. If the quantities of water absorbed and transpired in equinormal 
solutions of acids and alkalies are compared, the serial weighings show 
that tomato plants function better in an alkaline medium than in one 
of acid. 
In tables VII and VIII are seen also the effects of the solutions 
upon the amounts of water retained by the plants. In every case the 
acid inducing the higher absorption and transpiration increased the 
retention of water. This correspondence is not so marked, however, 
in the case of the alkaline solutions 5, 7, 12, and 13 (table VIII). 
The wilting observed in solutions 2, 5, 8, ii, and 12 (table VII) 
is the result of transpiration exceeding absorption, while that in solu- 
tions 7, 10, and 13 (table VII) and 4 (table VIII) as well as that in 
3) 4» 5» 6, 7, 12 and 13 (table IX), 4 (table X) is primarily a loss in 
food constituents within the plant. Similar facts were mentioned in. 
an earlier paper (5). These few data upon wilting in relation to the 
different solutions show nearly as many wilting coefficients for plants 
as there are solutions, atmospheric conditions and energy relations 
within the plants. 
The reduction of the water content to incipient wilting and perma- 
nent wilting can be studied more easily in this manner, and the method 
here used should be of great use in ecological investigations on that 
account. 
4. The addition to a solution of HCl n/Soo of any salt in the same 
molecular concentration inhibits in all cases the action of the acid and 
increases the amount of water absorbed and transpired. The different 
salts are unequally effective in this regard. The curves in figures 
I to 4 represent graphically the course of the reaction. In the series 
of chlorides (table IX) K is more powerful in producing an increase in 
the water requirement of the plants than Na or Ca. The general 
grouping of these ions is very similar to that given for the kations in 
