Rufty T W, Raper C D, Huber S C
United States Department of Agriculture, Agricultural Research Service, Raleigh, NC 27650, USA.
Can J Bot. 1984;62:501-8. doi: 10.1139/b84-074.
Alterations in internal partitioning of carbon were evaluated in plants exposed to limited nitrogen supply. Vegetative, nonnodulated soybean plants (Glycine max (L.) Merrill, 'Ransom') were grown for 21 days with 1.0 mM NO3- and then exposed to solutions containing 1.0, 0.1, or 0.0 mM NO3- for a 25-day treatment period. In nitrogen-limited plants, there were decreases in emergence of new leaves and in the expansion rate and final area at full expansion of individual leaves. As indicated by alterations in accumulation of dry weight, a larger proportion of available carbon in the plant was partitioned to the roots with decreased availability of nitrogen. Partitioning of reduced nitrogen to the root also was increased and, in plants devoid of an external supply, considerable redistribution of reduced nitrogen from leaves to the root occurred. The general decrease in growth potential and sink strength for nutrients in leaves of nitrogen-limited plants suggested that factors other than simply availability of nitrogen likely were involved in the restriction of growth in the leaf canopy and the associated increase in carbon allocation to the roots.
在氮供应受限的植株中评估了碳的内部分配变化。营养期未结瘤的大豆植株（大豆（Glycine max (L.) Merrill，品种‘兰塞姆’））在含有1.0 mM硝酸根的条件下生长21天，然后在25天的处理期内分别置于含有1.0、0.1或0.0 mM硝酸根的溶液中。在氮素受限的植株中，新叶的出现、单叶的扩展速率以及完全展开时的最终面积均有所下降。从干重积累的变化可以看出，随着氮素有效性的降低，植株中可利用碳的更大比例被分配到了根部。还原态氮向根部的分配也增加了，并且在没有外部氮素供应的植株中，发生了还原态氮从叶片向根部的大量重新分配。氮素受限植株叶片中养分的生长潜力和库强普遍下降，这表明除了单纯的氮素有效性之外，其他因素可能也参与了叶冠层生长的限制以及向根部碳分配的相应增加。
