22 MASS. EXPERIMENT STATION BULLETIN 398 



with brome grass {Bromiis inermis Leyss.), meadow fescue (Festuca elatior L.), 

 perennial rye grass {Lolium perenne L.), and timothy (Phleum pratense L.). 



The number of tillers was closely associated with the height of the plants, those 

 at 70°F. being the tallest at 50 days. Foliage and stem color were affected by sol 

 temperature. The plants at 50° were a dark green, and those at 60° were inter- 

 mediate between the dark green at 50° and the light green at 70° and above. 



There were enough replications so that half the containers were available for 

 shifting of temperatures, the remaining half being kept at the same temperature 

 as at the start of the test. The shifted temperatures were 20 degrees higher or 

 lower than the original temperatures. By this means it was possible to corrob- 

 orate the earlier conclusions made at the 50-day period. Plants which had been 

 at 50° F. and were dark green, prostrate in habit, short, and with few tillers, re- 

 sponded soon to the 70° soil temperature by assuming the characteristics of the 

 check at 70°. On the other hand, the plants at 70°, when shifted to 50°, became 

 prostrate in habit, dark green in color, and stopped growing. At temperatures 

 of 80° and 90°, the check plants and those shifted from 60° and 70° were not in a 

 healthy state of activity; but the unhealthy plants shifted from 90° to 70° and 

 from 80° to 60° resumed the healthy appearance of the check plants for these 

 temperatures. 



In the final stages, the plants at 90° F. soil temperature were very poor. Sev- 

 eral had died and the remainder were stunted and dark green in color. The 

 plants at 50° and 60° had the most and tallest spikes, but the foliage at the base 

 was sparse. The plants at 70° had thick foliage at the base indicating continued 

 vegetative activity. These plants also had the greatest dry weight. It also 

 appears that soil temperatures lower than 70° give greater dry weights than those 

 above 70°. Since careful attention was given to supplying water, the experiment 

 indicates that soil temperature is the governing factor, and not drought, which 

 is frequently associated with long hot spells of weather. 



DEPARTMENT OF CHEMISTRY 

 Walter S. Ritchie in Charge 



Chemical Investigations of the Onion. (Emmett Bennett.) The preliminary 

 work on the characterization of the soluble carbohydrates of the Ebenezer onion 

 as reported last year has been extended. The titration of the hydrolyzed sugars 

 with standard iodine and alkali and the determination of the fructose both indi- 

 cate that the total sugars are approximately two-thirds d-fructose. Syrups of 

 the total hydroh zed sugars yielded crystals with a specific rotation of [-41°Jd, 

 which is of the order expected for a mixture of d-glucose and d-fructose in the 

 ratio of 1 to 2. 



By removal of the reducing sugars, a preparation was obtained having a 

 specific rotation of about [+48°Jd, and after inversion about L-17°Jd. This, 

 together with the large negative enhancement noted on solutions after inversion, 

 is a strong indication that the chief non-reducing sugar is sucrose. 



The present work is concerned with metabolic changes which occur in the cell 

 during growth. Samples were taken at intervals during the growing season. At 

 mid-season onions were collected and divided into equal groups, some of which 

 were placed in total darkness for different periods of time. The many forms of 

 nitrogen have been determined as well as the sulfur compounds, organic acids, 

 and carboyhdrates. 



