Dickson Richard E., Isebrands J. S., Tomlinson Patricia T.
USDA Forest Service, North Central Forest Experiment Station, P.O. Box 898, Rhinelander, WI 54501, USA.
Tree Physiol. 1990 Dec;7(1_2_3_4):65-77. doi: 10.1093/treephys/7.1-2-3-4.65.
Carbon distribution and metabolism by northern red oak seedlings (Quercus rubra L.) were followed for 72 h after a 30-min photosynthetic exposure to (14)CO(2). Approximately 50% of the assimilated carbon was lost during this time, presumably through respiration. Most of the (14)C recovered in the plant remained in the source leaf. Most of the exported (14)C was found in stems and especially roots. Position of the source leaf did not affect distribution of translocated (14)C; however, upper source leaves retained slightly more (14)C than lower source leaves. Most (14)C in all tissues was found initially in sugars. Labeled carbon in this fraction decreased rapidly and increased in other chemical fractions, particularly residue (structural carbohydrates and lignin). More (14)C was incorporated into residue than into any other chemical fraction, indicating continued growth by each of the tissues during the lag stage of seedling development. Labeled carbon increased in proteins for 6 to 12 h after treatment, then remained essentially constant for the remainder of the transport period, indicating both rapid incorporation of the pulsed (14)C into, and slow turnover of, the labeled protein components. In source leaves, (14)C incorporated into starch in the light was lost during the dark period, a typical diurnal storage pattern. In stems, (14)C in starch increased for 12 h, then decreased during the dark period, and then increased during the rest of the transport period. This pattern indicates that stems have both diurnal and long-term storage pools of starch. In roots, (14)C in starch increased rapidly for 12 h, then remained constant for the rest of the transport period, indicating primarily long-term storage in this tissue. Peak (14)C in amino acids in taproot preceded that in stem tissue, indicating recycling of (14)C from the roots to the shoot in amino acids.
在北方红栎幼苗（Quercus rubra L.）经30分钟光合暴露于（14）CO₂后，对其碳分布和代谢进行了72小时的追踪。在此期间，约50%的同化碳损失，推测是通过呼吸作用。植物中回收的大部分（14）C仍留在源叶中。大部分输出的（14）C存在于茎中，尤其是根中。源叶的位置不影响转运的（14）C的分布；然而，上部源叶比下部源叶保留的（14）C略多。所有组织中的大部分（14）C最初存在于糖类中。该部分中标记的碳迅速减少，而在其他化学组分中增加，特别是在残渣（结构性碳水化合物和木质素）中。更多的（14）C被整合到残渣中，而不是其他任何化学组分中，这表明在幼苗发育的滞后期，每个组织都在持续生长。处理后6至12小时内，标记的碳在蛋白质中增加，然后在运输期的剩余时间内基本保持不变，这表明脉冲式（14）C迅速整合到标记的蛋白质组分中，且标记蛋白质组分的周转缓慢。在源叶中，可以看到在光照下整合到淀粉中的（14）C在黑暗期损失，这是典型的昼夜储存模式。在茎中，淀粉中的（14）C增加12小时，然后在黑暗期减少，然后在运输期的其余时间增加。这种模式表明茎既有淀粉的昼夜储存池，也有长期储存池。主根中氨基酸的（14）C峰值先于茎组织中的峰值，这表明（14）C以氨基酸的形式从根向地上部循环。
