Factors Affecting the Acetylene to 15N2 Conversion Ratio in Root Nodules of Myrica gale L.
AUTOR(ES)
Schwintzer, C. R.
RESUMO
When nodules of actinorhizal plants are exposed to acetylene, there is often an initial peak rate of acetylene reduction followed by a decline and a partial recovery. Treatment of hydroponically grown Myrica gale L. with water deficiency or dark stress increased the magnitude of the acetylene-induced decline and decreased the extent of the recovery. When N2 fixation was measured with 15N2 in unstressed plants, the ratio of acetylene reduction (peak) to N2 fixation prior to acetylene exposure was 3.73 [plus or minus] 0.14 (mean [plus or minus] SE). This value does not differ significantly (P < 0.05) from the theoretical minimum value of 4.0. In water-stressed plants the conversion ratio for the peak rate was greater (4.32 [plus or minus] 0.10) and in dark-stressed plants it was lower (2.54 [plus or minus] 0.33) than 4.0. The conversion ratio for the recovered rate of acetylene reduction was much lower than 4.0 in all cases, with mean values ranging from 1.16 to 2.60. We conclude that the peak rate of acetylene reduction provides the most reliable estimate of N2 fixation. The recovered rate of acetylene reduction consistently underestimates N2 fixation, sometimes severely, and thus measurements of acetylene reduction made in closed systems also underestimate N2 fixation to varying degrees.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=159629Documentos Relacionados
- Purification of Hemoglobin from the Actinorhizal Root Nodules of Myrica gale L.
- The Resistance of the Diffusion Barrier in Nodules of Myrica gale L. Changes in Response to Temperature but Not to Partial Pressure of O2.
- Pathways of Nitrogen Assimilation in Cowpea Nodules Studied using 15N2 and Allopurinol 1
- Azolla-Anabaena azollae Relationship: V. 15N2 Fixation, Acetylene Reduction, and H2 Production 12
- Reduction of Acetylene to Ethylene by Soybean Root Nodules