242 Varietäten, Descendenz, Hybriden. — Pl^siologie. 



ovarical treatment. (Bot. Gaz. LI. p. 241—257. pl. 14—16. 

 Apr. 1911.) 



A resume of the subject, including a description of the tech- 

 nique and character of the plants employed together with the results 

 of the culture of the affected species through a number of genera- 

 tions. That the sum of heredity characters in pedigreed lines of 

 plants may be altered by Solutions applied to the ovaries in the 

 stage immediately preeeding fertilization is further confirmed; one 

 of the earliest derivatives secured in this manner having been 

 carried to the fifth generation without showing indications of retur- 

 ning to the parental type. Moore. 



Clark, E. D., The nature and functionof the plant oxi- 

 dases. (Torreya, XL p. 23—31, 55-61, 84—92, 101—110. Feb., 

 Mch, Apr., May. 1911.) 



A general historical account of the occurrence of the several 

 oxidases found in plants, as well as their role and nature. Experi- 

 mentally the distribution and localization of oxidases and catalase 

 in a wide ränge of plants was studied, using a series of different 

 oxidase reagents under control conditions. The extent of the distri- 

 bution of those chromogens which are oxidized to colored Compounds 

 by natural oxidases of the plants involved, was also investigated. 

 A summary of the general conclusions is as follows: 



1. The oxidases are of very wide distribution among the flowe- 

 ring plants; peroxidases, expecially, being present in about seventy- 

 five per cent of all the specimens examined, while oxigenases 

 (direct oxidases) are less widely distributed, being found in one half 

 of the plants used. Catalase may be said to be universally distri- 

 buted, since there were only a few cases in which it was not found. 



2. The leaves, stems, roots and food-storage organs of the plants 

 seem to contain the greatest amounts of the oxidases. The flowers 

 and fruit were in many cases comparatively poor in oxidases. In 

 regard to the fruits this Statement must be qualified because dry 

 seeds of somewhat uncertain age were the onty available material 

 of certain species. 



3. Our experience with a great many parallel tests, using the 

 different oxidase reagents upon a great variety of vegetable tissues 

 show that all of the reagents seem to detect the same substance or 

 substances, for if one reagent gave a positive test the others gene- 

 rally acted in like manner. The phenolphthalin and indo-phenol 

 reagents gave positive results in more cases than the others. This 

 is undoubtely due to their greater ease of oxidation, for they are 

 spontaneously oxidized by the air. 



4. It is probable that in the presence of acid juices in the plant 

 the latter does not form oxidases or eise they are immediately 

 destroyed by the acid. It was shown that the inhibiting effect of 

 acids upon the action of oxidases seemed to be a function of the 

 concentration of the hydrogen ions. 



5. Among plants the chromogens are found to the greatest 

 extent in certain orders such as the Liliales, Orchidales, Ranales, 

 and most frequently of all in the latex plants of the Convolvulaceae, 

 BoragUiaceae, Labiatcie, Solanacecie, Rubiaceae, Compositae, etc. 

 Active oxidases are also likely to be associated with chromogens 

 in the latex plants. Moore. 



