Schweitzer L E, Harper J E
Department of Agronomy, Purdue University, West Lafayette, Indiana 47907.
Plant Physiol. 1985 May;78(1):57-60. doi: 10.1104/pp.78.1.57.
The objectives of this study were to determine the effect of light enhancement and hastened reproductive development on nitrogen and dry matter accumulation by field-grown soybean (Glycine max [L.] Merr.). The impacts of photosynthate supply and reproductive development on change in the season-long profiles of in vivo leaf nitrate reductase (NR) activity and root nodule acetylene reduction (AR) activity were evaluated.Light enhancement resulted in significant increases in dry matter accumulation, root nodule fresh weight and AR activity. Seed yield was increased in both light enhanced treatments in 1978 and in one in 1979.Hastened flowering and seed development was accomplished through photoperiod manipulation within a single genotype. Seasonal decline in leaf NR activity was most rapid in plants entering reproductive development early. An early increase in root nodule fresh weight and AR activity was also observed in response to this treatment and was followed similarly by early decline.The addition of high levels of soil-applied nitrogen increased leaf NR activity and delayed late season decline in NR activity for both control and early reproductive plants. Nitrate supply was therefore implicated as limiting to leaf NR activity during the decline associated with flowering and early seed development. A limited additional increase in leaf NR activity was observed in response to light enhancement plus soil-applied nitrogen. As no significant increase in leaf NR activity was observed in response to light enhancement alone, leaf nitrate supply was further implicated as more limiting to leaf NR activity than was photosynthate supply during flowering and early seed development.
本研究的目的是确定光照增强和加速生殖发育对田间种植大豆（Glycine max [L.] Merr.）氮素和干物质积累的影响。评估了光合产物供应和生殖发育对活体叶片硝酸还原酶（NR）活性和根瘤乙炔还原（AR）活性季节性变化的影响。光照增强导致干物质积累、根瘤鲜重和AR活性显著增加。1978年，两种光照增强处理的种子产量均有所提高，1979年其中一种处理的种子产量提高。通过对单一基因型进行光周期处理实现了开花和种子发育的加速。在早期进入生殖发育的植株中，叶片NR活性的季节性下降最为迅速。对这种处理还观察到根瘤鲜重和AR活性早期增加，随后同样是早期下降。添加高水平的土壤施用氮肥增加了叶片NR活性，并延缓了对照植株和早期生殖植株NR活性在生长后期的下降。因此，在与开花和早期种子发育相关的下降过程中，硝酸盐供应被认为是叶片NR活性的限制因素。在光照增强加土壤施用氮肥的情况下，观察到叶片NR活性有有限的额外增加。由于单独光照增强未观察到叶片NR活性显著增加，因此在开花和早期种子发育期间，叶片硝酸盐供应被进一步认为比光合产物供应对叶片NR活性的限制更大。
