ISSN:
1399-3054
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
The influence of shoot transpiration on the rates of growth and nitrogen fixation was investigated in Pisum sativum L. cv. Rondo. In short term experiments, rates of transpiration and acetylene reduction of intact plants were measured simultaneously, using air-tight perspex vessels enclosing the basal part of the nodulated root. In long term experiments, accumulation of dry matter and reduced nitrogen in the plant were determined as well. Transpiration rate changed diurnally and was varied by manipulating the vapour saturation deficit or the flow rate of the air in the growth cabinet. The rate of acetylene reduction declined after subjecting intact plants to high transpiration rates. This decline was accompanied by a desiccation of the root nodules. Dry matter and reduced nitrogen accumulation were not affected by transpiration rate. At low transpiration rate reduced nitrogen content of the root nodules was higher than at high transpiration rate. However, in these nodules the rate of acetylene reduction was not significantly affected. It is concluded that the nitrogenase activity of pea root nodules is insensitive to changes in the flow rate and the organic N concentration of the xylem sap within a wide range of transpiration conditions under the applied growth conditions.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1399-3054.1984.tb05183.x
