ANNUAL REPORT, 1938 35 



The Effect of Storage and Processing on the Carbohydrates of Some Varieties 

 of Edible Onions. (Emmett Bennett.) Onion storage ib of vital interest to the 

 grower because it is often accompanied by considerable losses. Before ideal 

 storage conditions can be defined, it is necessary to determine the nature of these 

 losses and ascertain the effect of different storage conditions. 



Consistent with this plan "seed" (Yellow Globe Danvers) and "set" (Ebenezer) 

 onions were stored in a warm dry room, in a basement, and in a commercial 

 storage, from October 14 to February 14. These storages will be referred to here- 

 after as A, B, and C respectively. Storage A represented relatively high tempera- 

 tures and low relative humidity; C, relatively low temperatures and high relative 

 humidity; and B, conditions intermediate between A and C. Before and after 

 storage representative samples of both "seed" and "set" onions were analyzed 

 to note changes in composition. 



The following results were obtained from the crop of 1937. Before storage, 

 "seed" and "set" onions consisted of approximately 11 percent of dry matter, 

 which was principally sugars. Reducing sugars were dominant in the "seed" 

 and sucrose in the "set". 



The "seed" in storages A and B had either sprouted or rotted so badl}- that the 

 shrinkage was not recorded. Those in storage C shrunk 12 percent. No market- 

 able onions were obtained from storage A, while 15 percent were obtained from B 

 and 56 percent from C. The "set" onions from storages A, B, and C shrunk 

 24, 13, and 6 percent respectively, and yielded 43, 73; and 88 percent of market- 

 able onions. The greater percentage of marketable "set" onions was probably 

 due to their greater maturity. The analyses indicated that approximately one- 

 eighth of the total sugars was lost regardless of storage. 



Since a considerable quantity of onions are consumed in boiled form, changes 

 effected by boiling were also determined. This treatment caused a loss of total 

 sugars slightly greater than that recorded in storage. 



These data indicate the following: 



1. Sucrose is the storage product of the Ebenezer onion. 



2. The chief losses in storage were from rotting and sprouting. 



3. Relatively low temperatures and high relative humidity retarded the 

 above losses. 



4. The different conditions of storage employed caused no significant loss 

 in the content of total sugar in the Ebenezer onion which did not rot or sprout. 



Investigations of Some Physical and Chemical Properties of Mosaic Viruses. 



(Monroe E. Freeman.) Mosaic diseases of plants cause severe losses in many 

 crops of economic importance in Massachusetts. It was recently shown that 

 tobacco mosaic is caused by a virus of protein nature. Additional evidence 

 indicates that many other mosaic diseases are caused by similar agents. Not 

 much is known, however, about their behavior or properties. This study has 

 been undertaken in the expectation that such knowledge may be of assistance 

 in devising methods to control these diseases. 



The virus in juice from infected plants remains active, in some cases, for long 

 periods of time; in other cases, for only a few hours. This property, longevity 

 in vitro, is different in different viruses and is used as a means of identification. 

 Why the virus loses its infectious ability under these conditions or why the viruses 

 differ so markedly in this respect is not known. Since oxidation may play a 

 prominent role, a study of this possibility has been undertaken by measuring 

 the effect of acidity and oxidation potential on two viruses of the potato mosaic 

 group. The acidity ranges of stability and inactivation were determined for the 

 viruses of potato rugose mosaic. The two react quite differently and this affords 

 a very simple means of separation. Five acids and two bases gave essentially the 



