Pregitzer Kurt S., Dickmann Donald I., Hendrick Ron, Nguyen Phu V.
Department of Forestry, Michigan State University, East Lansing, MI 48824-1222, USA.
Tree Physiol. 1990 Dec;7(1_2_3_4):79-93. doi: 10.1093/treephys/7.1-2-3-4.79.
The effects of water, nitrogen (N), and genotype on whole-tree carbon and nitrogen partitioning were examined in two Populus genotypes grown from cuttings in large pots set in the ground. Four replicate trees from each genotype/water/N treatment combination were harvested in either August, September, or November of their first year of growth. Aboveground biomass was linearly related to total leaf area. Clones allocated photosynthate differently. Populus tristis x P. balsamifera cv. Tristis #1 produced 14.5 cm of fine roots (< 0.5 cm diameter) per cm(2) of foliage, whereas P. x euramericana cv. Eugenei only produced 4.0 cm of fine roots per cm(2) of foliage. The large diameter structural roots of Eugenei grew rapidly late in the growing season so that large-root biomass was 3.8 to 7.5 times greater in November than in mid-August. In both clones, the root system grew twice as fast as the stem and branches late in the year. During August, about 75% of total tree N was in the canopy, but at least 80% of the September N content was still present in November following leaf fall. The major site of N storage was the large diameter structural roots. Nitrogen concentrations in these roots doubled following bud set.
在种植于地面大花盆中的两种杨树基因型中，研究了水分、氮（N）和基因型对整株树木碳和氮分配的影响。从每种基因型/水分/N处理组合中选取四棵重复树，在其生长的第一年的8月、9月或11月进行收获。地上生物量与总叶面积呈线性关系。不同克隆对光合产物的分配不同。三角叶杨×香脂杨cv. Tristis #1每平方厘米叶片产生14.5厘米细根（直径<0.5厘米），而欧美杨cv. Eugenei每平方厘米叶片仅产生4.0厘米细根。Eugenei的大直径结构根在生长季节后期生长迅速，因此11月的大根生物量比8月中旬大3.8至7.5倍。在这两个克隆中，根系在当年后期的生长速度是茎和枝的两倍。8月期间，树木总氮的约75%在树冠中，但9月氮含量的至少80%在落叶后的11月仍存在。氮的主要储存部位是大直径结构根。这些根中的氮浓度在芽形成后翻倍。
