Elevated CO2 concentration around alfalfa nodules increases N2 fixation.
Elevated CO2 concentration around alfalfa nodules increases N2 fixation.
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DOI：
10.1093/jxb/erp287
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发表时间：
2010
影响因子：
6.9
通讯作者：
Schulze J
中科院分区：
文献类型：
--
作者：
Fischinger SA;Hristozkova M;Mainassara ZA;Schulze J
通过PEPC固定NO3-CO2为类菌体提供苹果酸，为N同化提供草酰乙酸。因此，该过程对于有效的固氮至关重要。众所周知，NO2固定取决于外部CO2浓度。本论文的假设是，根瘤暴露于CO2浓度升高时，苜蓿植物的固氮作用增强。因此，紫花苜蓿的种子植物在水培系统中生长，该系统允许根/根瘤隔室单独通气，避免任何气体泄漏到芽中。用2500 μl l−1（+CO2）或0 μl l−1（-CO2）含CO2的N2/O2气流（80/20，v/v）对根/根瘤隔室进行通气。在3周的实验期内，+CO2处理强烈增加了NO2固定，固氮和生长。更强烈的CO2和固氮与根瘤中的氨基酸和有机酸的单株量更高相一致。此外，在根瘤和木质部汁液中天冬酰胺的浓度增加。在+CO2处理的植物倾向于发展结节具有较高的%N浓度和个人的活动。在对具有低效根瘤（修复-）的植物的平行实验中，+CO2处理仍然没有效果。我们的数据支持结核CO2固定是有效固氮的关键的论点。结论是，战略，提高根瘤CO2固定将提高固氮和根瘤形成。此外，在水培和气培生长系统中，向根和根瘤施加足够的CO2对于生长和有效的固氮是必要的。
Nodule CO2 fixation via PEPC provides malate for bacteroids and oxaloacetate for N assimilation. The process is therefore of central importance for efficient nitrogen fixation. Nodule CO2 fixation is known to depend on external CO2 concentration. The hypothesis of the present paper was that nitrogen fixation in alfalfa plants is enhanced when the nodules are exposed to elevated CO2 concentrations. Therefore nodulated plants of alfalfa were grown in a hydroponic system that allowed separate aeration of the root/nodule compartment that avoided any gas leakage to the shoots. The root/nodule compartments were aerated either with a 2500 μl l−1 (+CO2) or zero μl l−1 (–CO2) CO2-containing N2/O2 gas flow (80/20, v/v). Nodule CO2 fixation, nitrogen fixation, and growth were strongly increased in the +CO2 treatment in a 3-week experimental period. More intensive CO2 and nitrogen fixation coincided with higher per plant amounts of amino acids and organic acids in the nodules. Moreover, the concentration of asparagine was increased in both the nodules and the xylem sap. Plants in the +CO2 treatment tended to develop nodules with higher %N concentration and individual activity. In a parallel experiment on plants with inefficient nodules (fix–) the +CO2 treatment remained without effect. Our data support the thesis that nodule CO2 fixation is pivotal for efficient nitrogen fixation. It is concluded that strategies which enhance nodule CO2 fixation will improve nitrogen fixation and nodule formation. Moreover, sufficient CO2 application to roots and nodules is necessary for growth and efficient nitrogen fixation in hydroponic and aeroponic growth systems.
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影响因子：
8.8
作者：
Keutgen, Anna J.;Pawelzik, Elke
通讯作者：
Pawelzik, Elke
影响因子：
7.4
作者：
CHRISTELLER, JT;LAING, WA;SUTTON, WD
通讯作者：
SUTTON, WD
影响因子：
9.7
作者：
Minchin, FR
通讯作者：
Minchin, FR
影响因子：
3
作者：
PHILLIPS, DA;NEWELL, KD;FELLING, CE
通讯作者：
FELLING, CE
影响因子：
7.3
作者：
Atkins, C;Smith, P;Thumfort, P
通讯作者：
Thumfort, P