R. Serraj et al., SALT STRESS INDUCES A DECREASE IN THE OXYGEN-UPTAKE OF SOYBEAN NODULES AND IN THEIR PERMEABILITY TO OXYGEN DIFFUSION, Physiologia Plantarum, 91(2), 1994, pp. 161-168
The effects of short-term NaCl-salinity on nodules of soybean (Glycine
maw L. cv. Kingsoy) were studied on hydroponically-grown plants. Both
acetylene reducing activity (ARA) and nodule respiration (O-2 uptake
and CO2 evolution) were immediately inhibited, and the stimulation of
them by rising the external partial pressure of O-2 (pO(2)) was dimini
shed by the application of 0.1 M NaCl in the nutrient solution. The pe
rmeability of the nodule to O-2 diffusion, estimated by O-2 consumptio
n or CO2 evolution, was significantly lower in the stressed nodules th
an in the control ones. The respiratory quotient of intact nodules and
the ethanol production of excised nodules were increased by low pO(2)
and by salt stress. These data confirm that in salt-stressed soybean
nodules, O-2 availability is reduced and fermentative pathways are sti
mulated.