Studies on the respiratory effect of dehydrated alfalfa meal in closed systems. I. Ascorbic acid and copper as possible factors in the reaction

1. 1. The respiratory effect of CO 2 production and O 2 consumption by dehydrated alfalfa meal in closed systems has been studied further. 2. 2. Increasing the water level and/or the temperature had the effect of increasing the respiratory effect and increasing the ascorbic acid (AA) destruction. 3. 3. Adding AA to a reconstituted system in graded amounts produced graded increases in the CO 2 output. 4. 4. Adding AA to alfalfa autoclaved in tubes with low, medium, and high levels of water produced an increase in CO 2 at all levels, the effect tending to be more pronounced at the higher levels. 5. 5. Adding AA to alfalfa autoclaved outside of the tubes gave an increase in CO 2 in some cases, and an irregular effect in other cases. 6. 6. The addition of NaCN to reconstituted alfalfa systems caused an inhibition of the respiratory effect. 7. 7. In an artificial system, AA with the help of a copper catalyst gave rise to significant amounts of CO 2 , whereas no effect was observed with oxalic, tartaric, citric, or lactic acid under this system. 8. 8. Adding copper in the form of a cuprocyanide complex to the artificial system produced much less CO 2 than when it was added in the form of cupric chloride. 9. 9. The above facts are discussed in relation to a new theory to account for the respiratory effect in the natural system.