Synthesis and accumulation of nitrite in soybean nodules supplied with nitrate.
Synthesis and accumulation of nitrite in soybean nodules supplied with nitrate.
复制标题
供给硝酸盐的大豆根瘤中亚硝酸盐的合成和积累。
DOI：
10.1104/pp.69.6.1429
复制
发表时间：
1982
期刊：
影响因子：
7.4
通讯作者：
J. Streeter
中科院分区：
文献类型：
--
作者：
J. Streeter
结瘤大豆（Glycine max [L.] Merr）在不含结合态氮或在营养液中持续供应硝酸盐的砂培中生长。中等硝酸盐浓度（30毫克N/升）对根瘤重量/株影响不大，而高硝酸盐浓度（100毫克N/升）则使根瘤重量/株在种植后30 ~ 60天收获并开始硝酸盐处理时降低70 ~ 80%.NO3-供应对根瘤中铵态氮、氨基氮和酰脲氮浓度的影响较小且不一致。相反，结核中硝酸盐和亚硝酸盐浓度与硝酸盐供应量成正比，与每株结核重量成反比。根瘤中硝酸盐或亚硝酸盐浓度与根瘤重量/株之间的相关性非常显著。大豆根瘤胞质溶胶中含有依赖于NADH的硝酸还原酶活性（典型活性为0.1微摩尔/毫克蛋白×小时）。利用一株硝酸还原酶缺失的日本根瘤菌突变株（61 A76），证明其胞质酶活性来源于宿主。硝酸盐抑制了硝酸还原酶缺失突变体形成的根瘤的生长。这些结核确实含有亚硝酸盐，尽管亚硝酸盐的浓度（每克鲜重约0.3微克N）相对于由R形成的结核中的亚硝酸盐浓度（每克鲜重约1.5微克N）较低。61 A76菌株。总体结果支持了硝酸盐对豆科植物根瘤生长的抑制与根瘤中硝酸盐的代谢直接相关的观点。
Nodulated soybean plants (Glycine max [L.] Merr) were grown in sand culture without combined N or with a continuous supply of nitrate in nutrient solution. Moderate nitrate concentration (30 milligrams N per liter) had little effect on nodule weight/plant while high nitrate concentration (100 milligrams N per liter) depressed nodule weight/plant by 70 to 80% with harvests 30 to 60 days after planting and initiation of nitrate treatments.The effect of nitrate supply on ammonium, amino, and ureide nitrogen concentrations in nodules was small and inconsistent. In contrast, nitrate and nitrite concentrations in nodules were directly proportional to nitrate supply and inversely proportional to nodule weight/plant. Correlations between nitrate or nitrite concentration in nodules and nodule weight/plant were highly significant.Cytosol from soybean nodules was found to contain NADH-dependent nitrate reductase activity (typical activity was 0.1 micromole per milligram protein x hour). A Rhizobium japonicum mutant (derived from strain 61A76) lacking nitrate reductase was employed to show that the cytosol enzyme activity is of host origin. Growth of nodules formed by the mutant lacking nitrate reductase was inhibited by nitrate. These nodules did contain nitrite although concentrations of nitrite (about 0.3 microgram N per gram fresh weight) were low relative to nitrite concentrations (about 1.5 microgram N per gram fresh weight) in nodules formed by R. japonicum strain 61A76. The overall results support the idea that the depression of legume nodule growth by nitrate is directly related to the metabolism of nitrate in nodules.