Seddigh M, Jolliff G D
Department of Crop Science, Oregon State University, Corvallis, Oregon 97331.
Plant Physiol. 1986 May;81(1):136-41. doi: 10.1104/pp.81.1.136.
The effects of increased sink-source ratios, induced by elevating night temperatures, on remobilization of (14)C-assimilates and N within field-grown soybeans (Glycine max [L.] Merr.) was investigated from preflowering to maturity. Raising the mean minimum night temperature for the entire growing season from 10 (check, uncontrolled) to 16 degrees C increased seed growth without appreciable effect on final leaf area. Increasing this temperature to 24 degrees C increased seed growth and reduced final leaf area. Leaves, stems, petioles, and pods acted as intermediate storage sites for (14)C assimilates. Only plants with higher night temperatures remobilized some of the stored assimilates during the period of rapid seed growth. Even the seeds in the 24 degrees C plants with the largest sink-source ratios did not utilize all the C-assimilates potentially available for remobilization. Nitrogen was readily remobilized from petioles, stems, and pods of all treatments as early as the beginning of seed development, but from the leaves only during late seed-filling. However, only plants with elevated night temperatures tended to remobilize all of the available N from vegetative tissues and pods. We concluded that a larger portion of stored assimilates may be remobilized to the seed if a strong seed sink can be sustained. It also appeared that with increasing sink-source ratios, N shortage might limit seed yield before a lack of C-assimilates would. A proposed model for soybean assimilate demand, distribution, partitioning, and remobilization is presented.
研究了夜间温度升高诱导的库源比增加对田间种植大豆（Glycine max [L.] Merr.）从开花前期到成熟期（14）C同化物和氮再转运的影响。将整个生长季的平均最低夜间温度从10℃（对照，未控制）提高到16℃，增加了种子生长，而对最终叶面积没有明显影响。将此温度提高到24℃，增加了种子生长并减小了最终叶面积。叶片、茎、叶柄和豆荚作为（14）C同化物的中间储存位点。只有夜间温度较高的植株在种子快速生长期间转运了一些储存的同化物。即使是库源比最大的24℃植株中的种子也没有利用所有潜在可用于转运的碳同化物。早在种子发育开始时，所有处理的叶柄、茎和豆荚中的氮就很容易被转运，但只有在种子灌浆后期叶片中的氮才被转运。然而，只有夜间温度升高的植株倾向于从营养组织和豆荚中转运所有可用的氮。我们得出结论，如果能够维持强大的种子库，那么更大比例的储存同化物可能会被转运到种子中。似乎随着库源比的增加，在碳同化物短缺之前，氮短缺可能会限制种子产量。本文提出了一个大豆同化物需求、分配、分配和再转运的模型。
