SOIL MOISTURE AND WILTING 



129 



The experiments with Tropaeolum were performed when the 

 plants had six or seven leaves and still appeared to be in healthy 

 condition. The results are given in table 6. 



TABLE 6 



Percentage of soil moisture at the time of wilting of similar plants of Tropaeolum 

 exposed to different evaporation conditions 



The results given in table 6 agree in a general way with those 

 given for Martynia and Physalis, but the individual variations 

 shown by Tropaeolum are much greater than in the other two 

 cases. This may well be due to the adverse conditions under 

 which the plants were growing. 



The results obtained from two cases in which the same plant 

 was successively exposed to two different rates of evaporation 

 and allowed to wilt are given in table 7. As in the cases of 

 Martynia and Physalis, the plants revived without the addition 

 of water, when they were transferred from the position with 

 high rate of evaporation to that with a lower one. These data 

 point to the same conclusion as do those previously given. 



TABLE 7 



Percentage of water left in the soil by the same plants of Tropaeolum wilting under 



different rates of evaporation 



