Researches on plant respiration V. On the respiration of some storage organs in different oxygen concentrations

Abstract

The CO2 production of the tubers of potato and artichoke, and the roots of carrots was measured continuously for several days at 25[degree] C by the Pettenkofer method, under a wide range of 02 conc. The normal respiratory rate in air for all the materials usually went through a typical 2-phase course: a rise to a maximum, and then a slower fall which in some cases reached a constant level. The first rise might be due to the evolution of dissolved CO2 as a result of temp. change. In potatoes the normal respiratory rate was maintained in various O2 concs., ranging between 6.2 and 98.6%; in artichokes, the rate was reduced with a reduction in O2 conc. at the lower O2 contents but when O2 content exceeded 20% there was no change. In carrots the respiration increased with every rise in O2 conc. A change from anaerobic to aerobic conditions was accompanied by a rapid rise in the respiration of potatoes but the increase before the normal rate was resumed did not always show a direct relation with the length of the period of anaerobiosis. In N2 the respiratory rate of potatoes, artichokes and red beet roots was reduced; in carrots the anaerobic rate gradually rose above the normal and maintained the increased rate for 117 hrs. At 100 hrs. the average CO2 production was 0.46, 2, 1.57 and 1.26 mg./100 g./hr. in potatoes, carrots, artichokes and red beet roots respectively. Indication of a seasonal drift of respiratory activity was observed both in pototoes and artichokes.