花生根瘤菌共生吸氢和固氮的某些特性

Some Characteristics of H_2-uptake and C_2H_2-reduction of Rhizobium arachis in Symbiotics State

用花生根瘤菌某些Hup^+和Hup^-菌株作回接,有接种的植株其根瘤数比对照多。所试菌株在共生条件下表现吸氢和乙炔还原活性。离体根瘤 72 h内其吸氧活性表现起初较低,随后逐渐升高,而后又逐渐下降;但乙炔还原活性则随时间的延长逐渐下降。根瘤吸氢依赖于氧并受CO的抑制。10％外源分子氢可提高乙炔还原活性20～60％。不同生长期的吸氢和乙炔还原活性以盛花期为最高。

All of the nodules which inoculated with Rhizobium arachis HUP+ strains(L4_3, 351 and E2) and HUp-strainsCC4, 009 andl 033)showed H2-uptake activity. In full bloom stage, both H2 uptake and C2H2-reduction activities were the highest among the different growing states. The H2-up take activity depended on O2 and drastically inhibited by carbon monoxide in nodules. A 72-hrs-dy namic of H2-uptake and C2H2-reduction from the nodules has been obtained. After detachment, nodules were placed in room temperature and kept in proper moisture and the H2-uptake and C2Hz-reduc tion activities were measured respectively at different times. The results showed that C2H2- reduction activity decreased gradually during 24-hrs course. But the H2-uptake activity increased gradually during 24-hrs course and reached maximum at the end. After which, H2-uptake activity decreased gradually. However, the increase of H2-uptake activity during the 24-hts couuse did not appear when nodules were previously treated with 0. 05 mol/1 succinate or pyruate. C2H2-reduction activity in nodules was significantly promoted by H2. In the presence of 10% H2, the C2H2-reduction activities of the nodules detached for 3 hrs and 24 hrs increased 20% and 60% respectivity ; when treated with 0. 05 moI/l succinate, the activity of nodules detached for 24 hrs only increased 30%. From the evidences obtained, there is a close relationship between the Hi-uptake and nitrogen fixation in peanut plant.