56 



HISTOLOGIC PEOPERTIES AND REACTIONS. 



phide, sodium hydroxide, sodium sulphide, calcium ni- 

 trate, uranium nitrate, strontium nitrate, cobalt nitrate, 

 copper nitrate, cupric chloride, barium chloride, and mer- 

 curic chloride. 



The following is a summary of the reaction-intensi- 

 ties: 



9. COMPAEISONS OF THE StAECHES OF CeINUM 

 LONGIFOLIUMj C. MOOEEI, AND C. POWELLII. 



In histologic characteristics, polaiiscopic figures, 

 reactions with selenite, reactions with iodine, and quali- 

 tative reactions with various chemical reagents it will 

 be found that the starches of the parents and hybrid 

 exhibit not only properties in common in varying degrees 

 of development but also individualities, the sum of 

 which in case of each starch is distinctive of the starch. 

 The starch of the hybrid is in form, characters of the 

 hilum, lamellse, and size in certain respects closer to 

 ^ne than the other parent, and in other respects as close 

 to one as to the other. There are larger numbers of 

 both aggregates and compound grains than are found 

 in Grinum longifolium, but not quite so many as in 

 C. moorei. The irregularities of the grains are more 

 prominent and more numerous than in C. longifolmm, 

 but less than in G. moorei. An abrupt deflection of elon- 

 gated, slender grains at or just distal to the slightly 

 eccentric hilum is seen, this peculiarity being absent 

 from C. longifolmm, but present in G. moorei. The 

 majority of the grains are not so broadened and flat- 

 tened as in (7. longifolium, yet more flattened than 

 in G. moorei. In size, the grains are more evenly 

 divided into elongated and broadened forms than in 

 case of either parent. In polariscopic flgures and ap- 

 pearances with selenite, and in the iodine reactions, the 

 hybrid shows on the whole a distinctly closer relationship 

 to G. moorei. In the qualitative reactions with chloral 

 hydrate, potassium iodide, potassium sulphocyanate, 

 potassium sulphide, sodium sulphide, sodimn salicylate, 

 copper nitrate, cupric chloride, and mercuric chloride 

 it is, on the whole, very much closer to G. moorei than 

 to G. longifolium. In some reactions there are certain 

 features that are much more like those of G. longifolium, 

 particularly in some of the processes with potassium 

 iodide and sodium sulphide. In the reactions with cop- 

 per nitrate, cupric chloride, and mercuric chloride the 

 starch of the hybrid exhibits certain very interesting 

 pecidiarities, especially with reference to excess or deficit 

 of parental extremes. 



Reaction-intensities Expressed hy Light, Color, and Tempera- 

 ture Reactions. 

 Polarization: 

 C. longifolium, high to very high, value 83. 

 C. moorei, high to very high, slightly higher than C. longifolium, 



value 85. 

 C. powellii, high to very high, the same as C. moorei, value 85. 

 Iodine: 

 C. longifolium, light to moderate, value 40. 

 C. moorei, moderate, higher than C. longifolium, value 50. 

 C. powellii, slightly to moderate, value 45. 

 Gentian violet: 

 C. longifolium, moderately deep to deep, value 60. 

 C. moorei, moderately deep to deep, deeper than C. longifolium, 



value 65. 

 C. powellii, moderately deep to deep, the same as 0. moorei, 

 value 65. 



Safranin : 



C. longifolium, moderately deep to deep, value 60. 



C. moorei, moderately deep to deep, deeper than C longifolium, 



value 65. 

 C. powellii, moderately deep to deep, the same as C. moorei, 

 value 65. 

 Temperature : 



C. longifolium, majority at 70 to 71°, all at 74 to 75°; mean 74.5°. 

 C. moorei, majority at 68 to 70°, all but rare grains at 70 to 71°; 



mean 70.5°. 

 C. powellii, majority at 65 to 67°, all at 68 to 69°; mean 68.5. 



In all five reactions the reactivities of G. longifolium 

 are lower than those of G. moorei in varying degree. 

 The reactivities of the hybrid are the same as those of 

 G. moorei in the polarization, gentian-violet, and safra- 

 nin reactions; intermediate in the iodine reaction; and 

 higher than those of either parent, but closer to G. moorei, 

 in the temperature reaction. In four of the five reactions 

 it is closer to the pollen parent, and in one intermediate. 



Table A 9 shows the reaction-intensities in percent- 

 ages of total starch gelatinized at definite intervals 

 (minutes). 



Vblocitt-eeaction Curves. 



This section deals with the velocity-reaction curves 

 of the starches of Grinum longifolium, G. moorei, and 

 G. powellii, showing the quantitative differences in the 

 behavior toward different reagents at definite time- 

 intervals. (Charts D 169 to D 189.) 



The most conspicuous features of this group of curves 

 are: 



(1) The closeness of all three curves, indicating not 

 only a closeness of the parent stocks, but also very little 

 modification of parental peculiarities in the hybrid. 



(3) The higher reactivity of the hybrid than of either 

 parent, excepting in the sodium salicylate reaction in 

 which it is at first intermediate and then the same or 

 practically the same as that of the pollen parent. 



(3) The tendency for all three curves to run close 

 together throughout the periods of the reactions. 



(4) The intermediate position of the G. moorei 

 curve throughout the series of reactions, excepting in the 

 reactions with sodium salicylate and barium chloride. 

 In the former it is practically the same as that of the 

 hybrid, and in the latter practically the same as that of 

 G. longifolium. It is of interest to note that while the 

 curves of the parents in the reaction vrith barium chlo- 

 ride are practically the same, the curve of the hybrid is 

 well separated (higher) from them. In many of the reac- 

 tions gelatinization goes on so rapidly during the first 

 5 minutes that there is but little differentiation of any 

 two or of all three, as the case may be. With proper 

 strengths of solution marked differences could undoubt- 

 edly be elicited. 



(5) The earliest period during the 60 minutes at 

 which the three curves are so separated as to show the 

 most marked differences between them varies with the 

 different reagents. Approximately, this period occurs 

 within 5 minutes in the reactions with pyrogallic acid, 

 nitric acid, sulphuric acid, hydrochloric acid, potassium 

 hydroxide, potassium iodide, potassium sulphocyanate, 

 sodium hydroxide, sodium sulphide, sodium salicylate, 

 calcium nitrate, strontium nitrate, and cobalt nitrate; 

 within 15 minutes in those with chromic acid, uranium 

 nitrate, mercuric chloride, copper nitrate, and cupric 

 chloride; at 30 minutes with chloral hydrate and potas- 

 sium sulphide ; and at 60 minutes with barium chloride. 



Reaction-intensities of the Htbeid. 



This section treats of the reaction-intensities of the 

 hybrid as regards sameness, intermediateness, excess, 

 and deficit in relation to the parents. (Table A 9 and 

 Charts D 169 to D 189.) 



