WATER RELATIONS OF SPECIES: COMPARISONS 299 



mediately on a torsion balance. They were then placed in a corked tube 

 with the cut surface of the petiole in water. After 24 hours in the dark, at 

 1 5°C, the leaves were blotted, re-weighed and dried in an oven. Prehminary 

 tests, conducted to determine the effect of age and position of the leaf on 



./ 



X 35 



lOOOi 



900 



800 



700 



z 



V 







I 



tr 

 a 



600 



500 



z 



'^OO- 



< 







300: [■ 



200 



w / 



„„ 1-OV^ 2>x 



6 10 12 1A 16 



TIME IN DAYS (JUNE I960) 



Fig. 5. Prunus padus. The effect of soil moisture tension on the rate of increase of 

 total leaf length. (1-24 June i960.) The container number (i, 2 or 3) and the number 

 of the shoot are at the end of the curve. Soil moisture tensions (atm) for container 

 I are shown beside corresponding points of curve I4; similarly for container 2, by 29; 

 and for container 3, by 35- W: see Fig. 2. 



