436 



DATA OF PROPERTIES OF STARCHES OF PARENT- AND HYBRID-STOCKS. 



The reaction with potassium iodide begins in a few 

 grains in 1 minute. Complete gelatinization occurs in 

 less than 1 per cent of the entire number of grains and 

 1 per cent of the total starch in 5 minutes; in about 2 

 per cent of the grains and 3 per cent of the total starch 

 in 15 minutes; in about 2.5 per cent of the grains and 

 4.5 per cent of the total starch in 30 minutes; in nearly 

 3 per cent of the grains and 7 per cent of total starch in 

 45 minutes ; and in about 5 per cent of the grains and 12 

 per cent of total starch in 60 minutes. (Chart D 92.) 



The hilum swells and the fissures present in the un- 

 treated grain become enlarged and more refractive but 

 no bubble was detected as in H. katherince. The hilum 

 swells more and the fissures thereat are more common 

 and become more enlarged and refractive, than in H. 

 katherince. The entire grain becomes very refractive 

 and the lamellae are not usually distinct, with the excep- 

 tion of one lamella, which often forms a line of demarca- 

 tion between the main body of the grain and a marginal 

 border which is even more refractive than the body of the 

 grain. This lamella and the refractive border are much 

 more frequent than in //. katherince. The fissures are 

 much deeper and more profusely branched than in H. 

 katherince. The course of gelatinization is varied, but the 

 most common form is for the border to become differen- 

 tiated into its component lamella? and quickly gelatinize 

 without the appearance of refractive granules, with the 

 exception of a marginal row of linear granules; the 

 process advances almost simultaneously in the body of 

 the grain along deep fissures through the mesial region, 

 forming a mass of very refractive granules surrounded 

 by one to few rows of linearly arranged granules. The 

 border may remain as a narrow, clear band, but fre- 

 quently after the linear granules bounding it are gela- 

 tinized, distortion may start at one point and spread 

 around the margin or be limited to one end. The starch 

 much more frequently breaks down into very refractive 

 granules and much less frequently into refractive masses 

 than in H. katherince. The form of gelatinization most 

 commonly observed in this species was not noted in 

 H. katherince. In some grains the most resistant starch 

 may be at the proximal end and sides nearby as is fre- 

 quently found in H. katherince, but it is much more 

 frequently located in the border of the main body of the 

 grain, this not having been observed in H. katherince. 



The gelatinized grains are swollen and slightly to 

 considerably distorted, more distortion than in //. kath- 

 erince. Many grains remain with refractive granules, 

 and many are little affected beyond the swelling of the 

 hilum and enlargement of fissures ; the reaction, however, 

 has advanced further in many more grains than in H. 

 katherince. 



The reaction with potassium sulphocyanate begins in 

 half a minute. Complete gelatinization occurs in about 

 1.5 per cent of the entire number of grains and 7 per 

 cent of the total starch in 5 minutes; in about 9.5 per 

 cent of the grains and 11 per cent of the total starch in 

 15 minutes; in about 17 per cent of the grains and 22 

 per cent of the total starch in 30 minutes ; in about 28 

 per cent of the grains and 34 per cent of the total starch 

 in 45 minutes ; and in about 33 per cent of the grains and 

 40 per cent of the total starch in 60 minutes. (Chart 

 D 93.) Many grains are wholly unaffected. 



The hilum swells but no bubble was detected, as noted 

 in //. katherince. A fissure which is frequently found at 

 the hilum in the untreated grain becomes enlarged and 

 sometimes more refractive ; this being much more prom- 

 inent than in H. katherince. The lamellae of some grains 

 become more distinct, notably one which may form a 

 boundary line between the main body of the grain and a 

 refractive border, and there occurs a gradual differentia- 

 tion of the lamellae in this border. (The refractive bor- 

 der is present in the untreated grain. ) The fissures are 

 deeper and more frequently branched than in H. kath- 

 erince. The most common type of fissure is thorn-like, 

 and also numerous radiating fissures are formed in 

 grains of a more rounded type, which fissures are not 

 similar to those usually found in H. katherince. The 

 methods of gelatinization described in H. katherince are 

 occasionally observed, but the most common type is quite 

 dissimilar to the usual methods in H. katherince. Gela- 

 tinization usually begins with the swelling of the hilum 

 and advances along the course of well-defined fissures 

 after considerable progress in the main body of the 

 grain, and the process often starts at the boundary 

 between this region and the border and then advances 

 through the border which loses its structure and becomes 

 semi-transparent, often with the exception of a narrow 

 very refractive marginal baud. In many grains no fur- 

 ther progress in gelatinization occurs, while in others 

 the process may start at one point of this semi-trans- 

 parent border followed by distention and much distortion 

 of the capsule, and the granules in the main body as well 

 as the more resistant layers of starch may undergo com- 

 plete gelatinization. The general methods above de- 

 scribed are not observed in H. katherince. The starch 

 in the mesial region of the main body of the grain is 

 disorganized with the appearance of brilliant irregularly 

 massed granules, usually more refractive and numerous 

 than in H. katherince. The marginal layers of the main 

 body of the grain become deeply striated and generally 

 disorganized into linear granules previous to gelatiniza- 

 tion, these are similar to but more frequently found 

 around the entire grain than in //. katherince. When 

 a border is present, as occurs in many grains, the reaction 

 usually spreads through this without the formation of 

 granules, but it may disorganize into granules if the 

 outermost refractive layer is gelatinized ; the gelatiuiza- 

 tion of such a border was not observed in H. katherince. 

 The breaking of the grain into a few fairly large refrac- 

 tive fragments previous to gelatinization is very rarely 

 observed, with much less frequency than in H . kalli erince. 



The gelatinized grains are much swollen and slightly 

 to considerably distorted, the distortion is more frequent 

 than in H. katherince. Many grains still contain a num- 

 ber of refractive granules which more frequently inclose 

 the entire margin of the grain or the main body within a 

 translucent border. The reaction has advanced to this 

 stage in many more grains, as well as reached complete 

 gelatinization of a much larger number than in H. 

 katherince. 



The reaction with potassium sulphide begins in a few 

 grains in half a minute. Complete gelatinization occurs 

 in less than 1 per cent of the entire number of grains and 

 total starch in 5 minutes ; in about the same percentage in 

 15 minutes; in about 1 per cent of the grains and 2.5 



