292 



Transactions of the Canadian Institute. 



[Vol. VII. 



plant in order to ascertain if that plant makes any increase, it is neces- 

 sary in all such investigations to base results upon estimates with similar 

 plants grown under similar conditions. 



The results of this experiment support the conclusions arrived at in 

 regard to the effect of nutrient solutions applied to leaves in the form of 

 a spray. There is not only a visible increase in number of leaves and in 

 length of stem, but also a substantial increase in dry weight and in 

 weight of ash. Since the actual content of ash in proportion to dry 

 weight is increased, there can remain no doubt that the leaves had 

 absorbed some of the substance applied in the form of a spray. 



VII. — The Effects of Strong Solutions Applied to the 

 CUT Ends of the Petioles of Foliage Leaves. 



It was necessary first to determine whether solutions when applied 

 to the cut ends of the petioles of leaves ascended through the blades. 

 It was found by chemical analysis that solutions did ascend through the 

 blade of the leaf even to the margin. This having been proved, it was 

 then possible to investigate the effects of solutions entering leaves in 

 this way. The leaves were placed in solutions as shown in Fig. 8, and 

 the records of the experiments are self-e.xplanatory. 



For the first series of experiments leaves of the following plants were 

 chosen : — Malva, Primula, Nicotiana, Ranunculus and Dicentra. 



In twenty-four hours after setting up the ex- 

 periment, solutions (HCl) and (H^,S04) produced 

 a decolorization of the leaf tissue from the base of 

 the leaves outwards in all the leaves, especially so 

 in the leaves of Primula and Nicotiana. This 

 decolorization, in some cases was slightly more 

 extensive in the region of the large veins, but had 

 when small the shape of a semicircle whose centre 

 was at the junction of the petiole and the blade 

 of the leaf. Solution (NH4OH) had caused a 

 blackening of the tissue in the part of the blade 

 nearest the petiole ; and had produced a deepen- 

 ing of the green colour out towards the margin. 

 Solution (NaHCOg) had caused a " frozen " ap- 

 pearance between the main veins, extending from 

 the margin inwards, especially so in the case of 

 Nicotiana. 



FIG. 8. 



S., solution used ; A., 

 cardboard cover to prevent 

 too rapid evaporation. 



