204 EXPERIMENT STATION RECOBD. 



isemicrystalllne condition. " Besides the occurrence of lycopersicin in crys- 

 talline form, carotin occurs as granules outside of the plastid in the ripening 

 red tomato, and one or more of the orange pigments occur in the fatty oils of 

 many fungi, and possibly In certain fruits, the detailed evidence of which can 

 not be presented liere." 



In attempting to ripen quickly some tomato fruits which were gathered green, 

 the fruits available were roughly divided into three lots, one of which was 

 placed near a south window in a room kept moderately warm both day and 

 night ; a second lot was wrapped In black paper and placed in a locker In the 

 laboratory where the temperature was usually 20° C. ; and the third lot was 

 incubated at a temperature of 35°. 



After the lapse' of a week, about half of the fruits near the south window 

 had reddened well. Those at a moderate temperature, and in complete dark- 

 ness in the locker, however, gave a larger number of ripe fruits, also with 

 higher color, than the first lot. The incubator fruits showed very little redden- 

 ing, but rather a preponderance of orange and yellow pigment. It was there- 

 fore obvious that the chemical effects of light were unimportant in the redden- 

 ing process. 



As to the affects of higher temperatures, " the red pigment of tomatoes, 

 lycopersicin, is partially or completely suppressed when green fruits are ripened 

 at a temperature of 30° or above, a yellow, orange, or orange red coloration 

 resulting. The inhibition of reddening is proportional to the temperature (be- 

 tween 30 and 37°) increase, and inversely related to the age of the fruits used. 

 The factors for reddening are not destroyed by high temperature, and a return 

 of the fruit to favoi'able conditions permits rapid pigmentation. 



" Fruits maintained in an oxygen-free atmosphere fail to redden at a nor- 

 mal ripening temperature. Fruits of the red peppers ripen normally at high 

 temperature, but the red arils of Momordica seem to follow the behavior of the 

 tomato. The chief pigments of red peppers and of the arils of Momordica ex- 

 hibit the absorption bands of lycopersicin. In the tomato lycopersicin forma- 

 tion follows the destruction of the chlorophyll, also certain other changes, sug- 

 gesting an increased permeability of the cell structures. Lycopersicin suppres- 

 sion at high temperature may be related to decreased acidity, but unknown 

 factors are concerned." 



"A study of the oxidase and peroxidase content was also undertaken, but 

 so far as the determinations have been carried, there is no correlation between 

 oxidase content and lycopersicin development." 



The effect of certain conditions upon the acidity of tomato fruits, B. M. 

 DuGGAB and M. C. Mekrill (Ann. Missouri Bot. Gard., 1 (1914), No. 2, pp. 237- 

 240)j — In the work reported in the abstract above reference is made to the 

 possible relation the total acid content of tomato fruits ripened at 30° C. or 

 above may have in hindering the development of pigment (lycopersicin) at 

 that temperature. " It was determined that the * total acidity for green, ripen- 

 ing, and ripe fruits, grown under the same conditions, is unexpectedly uniform, 

 amounting to 0.57 to 0.58 per cent citric acid.' The fruits .iust referred to 

 were of the same variety picked at the same time. The tests were made by 

 pulping thoroughly a weighed quantity of the tissue (15 gm.), diluting with 

 150 cc. distilled water, employing for each titration 25 cc. of this solution diluted 

 with distilled water to 50 cc, and titrating with tenth-normal NaOH. using 

 phenolphthalein as indicator. 



" There were no marked differences between the green and ripe stages within 

 the variety; yet the acidity of the green fruits of the red varieties in these 

 tests is somewhat higher, while the acid content of the green fruits of the 



