724 



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



With safranin the grains stain very lightly at once, 

 and in half an hour they are lightly to moderately colored 

 (value 38), slightly deeper than in both parents. The 

 color with safranin is a little deeper than with gentian 

 violet, as noted for both parents. 



In the aniline reactions the resemblances are closer 

 to R. elliottiana than to R. albo-maculata. 



Temperature Reactions. 

 The majority of the grains are gelatinized at 74° 

 to 76° C, and of all at 76° to 78° C, mean 77° C. The 

 temperature of gelatinization is slightly nearer that of 

 R. ellioltiana (mean 76.5°) than of R. albo-maculala 

 (mean 77.7°), practically exactly mid-intermediate. 



Effects of Various Reagents. 

 The reaction with chloral hydrate begins immediately. 

 Complete gelatinization occurs in about 89 per cent of 

 the grains and 99 per cent of the total starch in 3 

 minutes; in about 98 per cent of the grains and more 

 than 99 per cent of the total starch in 5 minutes. (Chart 

 D545.) 



The hilum becomes more distinct than in R. elliot- 

 tiana, but the reaction is more like that in this starch 

 than in R. albo-maculata, and the formation of bubbles is 

 of rarer occurrence than in R. elliottiana. No lamella? 

 are visible. A narrow, refractive band forms slowly about 

 the margin of the more resistant grains. Gelatinization 

 begins in the smaller grains and in the less resistant 

 larger grains in all parts of the interior at once — in the 

 more resistant grains it usually begins at the 2 distal 

 corners at which end the 2 canals from the hilum 

 as in R. albo-maculata, and in the others either at the 

 proximal end or at one distal corner. The progress of 

 gelatinization following these various methods of starting 

 has been described under R. albo-maculata. The gela- 

 tinized grains are moderately large and somewhat dis- 

 torted as in both parents. In this reaction R. mrs. roose- 

 velt shows qualitatively, on the whole, a closer resem- 

 blance to R. albo-maculata than to R. elliottiana. 



The reaction with chromic acid begins in half a 

 minute. Complete gelatinization occurs in about 0.5 per 

 cent of the entire number of grains and 6 per cent of the 

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

 grains and 67 per cent of the total starch in 15 minutes; 

 in about 66 per cent of the grains and 97 per cent of 

 the total starch in 30 minutes ; in about 95 per cent of 

 the grains and over 99 per cent of the total starch in 

 45 minutes ; complete gelatinization occurs in 100 per cent 

 of both the entire number of grains and total starch in 

 60 minutes. ( Chart D 546. ) 



The hilum becomes distinct very slowly as in R. albo- 

 maculata, but irregular fissuration at the hilum is less 

 noticeable than in that starch. Lamellar structure 

 may be noted in some grains as gelatinization proceeds. 

 Gelatinization begins at the hilum and is nearly the same 

 as noted under R. albo-maculata, except that the margin 

 is more often invaded by cracks than in R. albo-maculata 

 and the gelatinized grains are nearly always dissolved. 

 In this latter respect it varies widely from R. elliottiana 

 and is closer to R. albo-maculata. In this reaction R. 

 mrs. roosevelt qualitatively shows a closer relationship to 

 R. albo-maculata than to R. elliottiana. 



The reaction with pyrogallic acid begins in a few 

 grains immediately. Complete gelatinization occurs in 



about 2 per cent of the entire number of grains and 3 

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

 cent of the grains (the same as in 5 minutes) and 4 per 

 cent of the total starch in 15 minutes; in about 5 per cent 

 of the grains and 6 per cent of the total starch in 30 

 minutes; in about 6 per cent of the grains and 7 per 

 cent of the total starch in 45 minutes ; in about 6 per cent 

 of the grains (the same as in 45 minutes) and 8 per cent 

 of the total starch in 60 minutes. (Chart D 547.) 



The reaction with nitric acid begins in a few grains 

 immediately. Complete gelatinization occurs in about 3 

 per cent of the entire number of grains and 6 per cent 

 of the total starch in 5 minutes; in about 12 per cent 

 of the grains and 16 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 21 per 

 cent of the grains and 36 per cent of the total starch in 

 45 minutes; in about 27 per cent of the grains and 41 

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

 D548.) 



The reaction with sulphuric acid begins immediately. 

 Complete gelatinization occurs in about 86 per cent of the 

 entire number of grains and 97 per cent of the total 

 starch in 5 minutes; in more than 99 per cent of the 

 grains and total starch in 10 minutes. (Chart D 549.) • 



The reaction with hydrochloric acid begins imme- 

 diately. Complete gelatinization occurs in about 8 per 

 cent of the entire number of grains and 16 per cent of the 

 total starch in 5 minutes; in about 14 per cent of the 

 grains and 29 per cent of the total starch in 15 minutes ; in 

 about 32 per cent of the grains and 50 per cent of the total 

 starch in 30 minutes ; in about 44 per cent of the grains 

 and 61 per cent of the total starch in 45 minutes; in 

 about 52 per cent of the grains and 77 per cent of the 

 total starch in 60 minutes. (Chart D 550.) 



The hilum is not so distinct as in R. albo-maculata, 

 and is the same as in R. elliottiana. Gelatinization be- 

 gins at the hilum and the process is the same as that de- 

 scribed under R. albo-maculata, except that the gran- 

 ules and stria? are finer as in R. elliottiana. There are 

 more grains dissolved than in R. elliottiana, and about as 

 many as in R. albo-maculata. The gelatinized grains 

 are like those of the parents. In this reaction R. mrs. 

 roosevelt shows qualitatively a closer resemblance to 

 R. albo-maculata than to R. elliottiana, but there are 

 few marked differences in the behavior of the three 

 starches. 



The reaction with potassium hydroxide begins imme- 

 diately. Complete gelatinization occurs in about 4 per 

 cent of the entire number of grains and 9 per cent of the 

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

 grains and 14 per cent of the total starch in 15 minutes ; 

 in about 8 per cent of the grains and 15 per cent of the 

 total starch in 30 minutes; in about 16 per cent of the 

 grains and 25 per cent of the total starch in 45 minutes ; 

 in about 18 per cent of the grains and 38 per cent of the 

 total starch in 60 minutes. (Chart D 551.) 



The hilum is moderately distinct as in the parents, 

 and in only a few grains is there any evidence of the 

 lamellar structure as noted in nearly all the grains of 

 R. albo-maculata, and in more of those of R. elliottiana. 

 Gelatinization begins at the hilum as in R. albo-maculala 

 and the process is the same as in that starch. R. elliot- 

 tiana varies somewhat, but only slightly from the other 



