DEPARTMENT OF BOTANICAL RESEARCH. 67 



The biocolloid approaches more nearly to the condition of the 

 protoplast, however, when in common with all Uving matter it includes 

 some salts. The above mixtm^e treated with nutrient salts was not 

 available, but some plates in which the oat-protein was replaced by 

 bean-protein (to which had been added 0.8 per cent of nutrient salts) 

 were swelled in a parallel series at 15° C. with results as follows: 

 Distilled water 1,417 per cent, bog water 1,444 per cent, calcium 

 sulphate 0.048 gram, per liter 1,417 percent, swamp water 944 per cent, 

 calcium sulphate 0.128 gram per hter 1,083 per cent. 



Bog water and an equivalent calcium solution allow equal swelling, 

 but the increase in swamp water is much less and also less than in 

 the equivalent calcium solution, to which may be attributed most of 

 the retarding effect of the swamp-water derivatives. The swelling 

 of biocolloids and of living and dried sections of plants in distilled 

 water, bog water, and in a calcium solution of the same concentration 

 as the bog water are practically parallel. So far as known to the writer, 

 the effects of bog water are not attributable to any of its known 

 constituents, and its low oxj^gen-content as tested by Clements may 

 be responsible for its morphogenic and physiologic effects and its 

 domination as a factor in the habitat. 



Swamp water has been found to affect absorption and swelling in 

 the same manner as an equivalent solution of calcium sulphate. 

 Swelling and absorption are retarded by swamp water in salted 

 biocolloids and in sections of plants containing a large proportion of 

 pentosans and a low protein content. Biocolloids with a high protein 

 and salt content, on the other hand, show an enhanced absorption in 

 swamp water. Inferentially, plants of similar constitution would carry 

 on absorption readUy and thrive in swamp waters. Whether adaptation 

 to swamp habitats actually takes this course is not known. 



Colloidal Phenomena in the Protoplasm of Pollen Tubes: The Effect of Potassium 

 and Sodium on Hydration and Growth, hy Francis E. Lloyd. 



In continuation of previous work reported upon in 1916 and 1917, 

 attention was directed this year to the comparative effects of sodium 

 and potassium in the form of hydrate. The hydration capacity of 

 the protoplasm of the pollen of Phaseolus is increased by both hydrates, 

 but more by potassium than by sodium in equal concentrations, 

 viz, in N/3200 and N/6400, over that for water wdth 20 or 25 per cent 

 cane sugar, the same concentration of sugar being present in combin- 

 ation with the hydrates, the temperatures being the same for all. 



This increased hydration capacity expresses itself partly in swelling 

 in excess of that available for growth and partly in the amount of 

 growth. In the former case the pollen tubes burst before reaching 

 their maximum growth; in the latter case the amount of growth in 

 sodium is greater than that in potassium, and in the latter greater 



