Fellows R J, Patterson R P, Raper C D, Harris D
Battelle-Northwest, Richland, Washington 99352, USA.
Plant Physiol. 1987 May;84(1):456-60. doi: 10.1104/pp.84.2.456.
Nodulated soybean plants (Glycine max [L.] Merr. cv Ransom) in a growth-chamber study were subjected to a leaf water potential (psi w) of -2.0 megapascal during vegetative growth. Changes in nonstructural carbohydrate contents of leaves, stems, roots, and nodules, allocation of dry matter among plant parts, in situ specific nodule activity, and in situ canopy apparent photosynthetic rate were measured in stressed and nonstressed plants during a 7-day period following rewatering. Leaf and nodule psi w also were determined. At the time of maximum stress, concentration of nonstructural carbohydrates had declined in leaves of stressed, relative to nonstressed, plants, and the concentration of nonstructural carbohydrates had increased in stems, roots, and nodules. Sucrose concentrations in roots and nodules of stressed plants were 1.5 and 3 times greater, respectively, than those of nonstressed plants. Within 12 hours after rewatering, leaf and nodule psi w of stressed plants had returned to values of nonstressed plants. Canopy apparent photosynthesis and specific nodule activity of stressed plants recovered to levels for nonstressed plants within 2 days after rewatering. The elevated sucrose concentrations in roots and nodules of stressed plants also declined rapidly upon rehydration. The increase in sucrose concentration in nodules, as well as the increase of carbohydrates in roots and stems, during water stress and the rapid disappearance upon rewatering indicates that inhibition of carbohydrate utilization within the nodule may be associated with loss of nodule activity. Availability of carbohydrates within the nodules and from photosynthetic activity following rehydration of nodules may mediate the rate of recovery of N2-fixation activity.
在生长室研究中，对结瘤大豆植株（大豆[Glycine max (L.) Merr. cv Ransom]）在营养生长阶段施加-2.0兆帕的叶片水势（ψw）。在复水后的7天内，测定了胁迫和非胁迫植株叶片、茎、根和根瘤中非结构性碳水化合物含量的变化、植物各部分干物质的分配、原位根瘤比活性以及原位冠层表观光合速率。还测定了叶片和根瘤的ψw。在最大胁迫时，与非胁迫植株相比，胁迫植株叶片中的非结构性碳水化合物浓度下降，而茎、根和根瘤中的非结构性碳水化合物浓度增加。胁迫植株根和根瘤中的蔗糖浓度分别比非胁迫植株高1.5倍和3倍。复水后12小时内，胁迫植株的叶片和根瘤ψw恢复到非胁迫植株的值。胁迫植株的冠层表观光合作用和根瘤比活性在复水后2天内恢复到非胁迫植株的水平。胁迫植株根和根瘤中升高的蔗糖浓度在再水化后也迅速下降。水分胁迫期间根瘤中蔗糖浓度的增加以及根和茎中碳水化合物的增加，以及复水后迅速消失，表明根瘤内碳水化合物利用的抑制可能与根瘤活性的丧失有关。根瘤内碳水化合物的可用性以及根瘤再水化后光合活性产生的碳水化合物可能介导了固氮活性的恢复速率。
