---

作 者 ：门中华1;李生秀2

期 刊 ：植物营养与肥料学报 2005年 11卷 2期 页码：205-210

关键词：钼；冬小麦；硝态氮；氮代谢；

Keywords:molybdenum, winter wheat, nutrition solution, nitrate-N, nitrogen metabolism,

摘 要 ：采用全硝态氮霍格兰营养液为培养基质,在供应0(缺钼)、0.78(适钼)、2.74μmol/L(高钼)3种钼浓度下培养小麦.,分期测定其体内ＮＯ₃^--Ｎ、NH₄⁺-N、全Ｎ、吸氮量及硝酸还原酶活性.(ＮＲＡ).,研究钼对小麦ＮＯ₃^--Ｎ代谢的影响。结果表明.,ＮＲＡ受硝酸盐代谢库和贮存库之间的调节而不断变化.,但任何情况下钼对ＮＲＡ都有明显影响。培养初期适钼处理ＮＲＡ最高.,高钼次之.,缺钼最低.;培养后期由于缺钼处理的NO₃^--N浓度高于施钼处理.,ＮＲＡ随之增至最高。植株内NH₄⁺-N、ＮＯ₃^--Ｎ浓度之和在不同测定时间大致稳定.,ＮＯ₃^--Ｎ浓度高时则NH₄⁺-N浓度低.,反之亦然.,两者之间存在一定的负相关关系。稳定情况与钼供应有关.,适钼条件下培养开始时高的NH₄⁺-N与低的ＮＯ₃^--Ｎ浓度明显对应.,之后两者浓度接近.;缺钼条件下与此类似.,但NO₃^--N浓度变化不大.,NH₄⁺-N、ＮＯ₃^--Ｎ浓度之和最高.;高钼条件下NH₄⁺-N浓度一直高于NO₃^--N。作物由溶液吸收的NO₃^--N与作物的吸氮量一致.,适钼时最多.,高钼次之.,缺钼最少。从适钼时作物体内NH₄⁺-N、ＮＯ₃^--Ｎ浓度之和最低.,而吸氮量又最高可以看出.,合适的钼供应不但有利于NO₃^--N的吸收和向NH₄⁺-N转化.,也有利NH₄⁺-N向有机氮转

Abstract:Hoagland‘s solution with nitrate N as only N source, in which 0, 0.78, and 2.74 μmol/L Mo being separately added, was used to culture winter wheat seedlings, and NO₃^--N, NH₄⁺-N concentration in plant leaves, total uptake N in plants and nitrate-reductase activity (NRA) were measured at every 2 days for investigating the effects of Mo on nitrate N metabolism. Results show that NRA, as regulated by metabolism pool and storage pool, varied continuously during the cultural period. However, at any case, Mo had an obvious effect on it: at the onset of 4 days, the treatment with suitable Mo concentration was the highest in NRA, followed by that treated with high Mo concentration, and that deficient in Mo was the lowest. Thereafter, due to nitrate accumulation in high amount in plants, NRA in the Mo deficient treatment thus became the highest. Nitrate N was negatively correlated with ammonium N, and the sum of nitrate and ammonium concentration was almost stable at any measurement. When nitrate N concentration was higher, ammonium N would become lower, or in visa versa. Such a balance was closely related with Mo supply: at adequate concentration of Mo, the high concentration of ammonium N was opposite to low nitrate N at the onset of 4 days, since then, both concentrations trended to be the same level. The treatment of Mo deficient was similar to the adequate, but nitrate N was no great change and the sum of ammonium and nitrate N concentrations was higher. In contrast, ammonium N concentration in the high Mo treatment was higher than the nitrate concentration throughout the whole period of the culture. Crop uptake nitrogen, which agreed well with nitrate N reduction in the solution, was the highest in the treatment with suitable Mo concentration, followed by that with high Mo treatment while that deficient in Mo was the lowest. Considering the lower total concentration of nitrate and ammonium N in plants and the highest uptake of N by plants, it was clear that adequate Mo supply did not only promote nitrate uptake and transformation into ammonium, but also favored ammonium transformation into organic nitrogen and therefore played an important role in the nitrate N metabolism.

---