184 SOME RECENT RESEARCHES IN PLANT PHYSIOLOGY 



Working with such forms as Aspergillus, Sterigmatocystis, 

 Penicillium, Clonostachys, etc., he found that increase in 

 the osmotic pressure of the liquid medium results in 

 (a) Reduction in height of the aerial portion of the fungus 

 and the lateral dilatation of the cells constituting this 

 region; (6) the predominance of the submerged portion of 

 the mycelium relative to the aerial portion. In a certain 

 number of cases a great concentration of the medium 

 determines the complete immersion of the plant. There 

 is then manifested a profound alteration in the form of 

 the reproductive organs, which usually remain sterile. 



The results obtained with seedlings of Phaseolus, Pisum, 

 Lupinus, Zea, and Triticum, were also of interest. As a 

 rule the roots became more or less abnormal in their 

 macroscopic appearance and branching. Microscopical 

 examination also showed profound modifications in the 

 histology of the root. For example, haricot beans (Phase- 

 olus sp.) were grown in water and in Knop's solution to 

 which sodium chloride had been added to make a 1 per 

 cent, solution. The former developed normally, with a 

 large portion of the centre occupied by pith. The latter, 

 however, contained no pith, the centre being filled up with 

 the proto- and metaxylem, outside which was a thick layer 

 of secondary xylem. Furthermore, the central cylinder 

 was protected from the action of the medium by the early 

 development of abundant cork arising from the pericycle. 



EFFECT OF INCREASE AND DECREASE OF OSMOTIC PRESSURE 



UPON GROWTH AND IRRITABILITY. 



A great number of researches have been carried out 

 upon the effect of increase or decrease of osmotic pressure 

 upon growth and irritability. These have been treated 

 of by Livingston (1903), also by Loeb (1906, 1913), and 

 consequently they will be considered here very briefly. 



