WATER CONTENT OF PLANT AND SOIL, 33 



per cent of water in the plant at the time of dying. They 

 are taken from Comparative Plot II (See record of average 

 physical factors for this plob). These are the averages 

 from 36 pots of Zea mays and Phaseolus vulgaris. 



Effect of Physical Stimuli. 



„,.„_, NON- AVAILABLE WATBK IN DYING 



WATER IN SOIL. PLANT. 



Casf, I. (Reduced temperature). 



Zfa mays 5.7 40.4 



Phaseolus vulgaris 5.9 46.1 



Case II. (Intense shade). 



Zea mays 8.4 54.6 



Phaseolus vulgaris 8.8 56.7 



Case III. (Low to normal humidity). 



Zea mays 4.5 48.0 



Phaseolus vulgaris 5.9 31.9* 



Case IV. (High humidity). 



Zea mays 5.6 53.3 



Ph seolus vulga is 5.8 60.5 



*Partly diseased 



In determining the water in dying plants, great care was 

 taken to have the plants near the death point, and this being 

 the case the variations in the results from different condi- 

 tions may be ascribed partly to differences in plant vigor, 

 and partly to a change in the structure due to adaptation. 

 The intense shade in Case II. was without doubt the cause 

 of the high limit of soil water and the high per cent, of wa- 

 ter in the dying plants. The plants in this case were greatly 

 elongated in length. They were etiolated and lacked in 

 fibro-vascular tissues. As soon as they were deprived of a 

 water supply in the soil, they collapsed. The results from 

 Case IV. indicate that high humidity has a tendency to pro- 

 duce the same effect on the limit as shade, but to a less de- 

 gree. 



C. NON- AVAILABLE WATER IN SOILS ; HOW VARIED. 



1. Effect of Increased Heat {and Light). 



In the consideration of the effects of heat, light must be in- 

 cluded, because it was inseparably connected with the high 



