Seasonal changes in photosynthesis, nitrogen content and nitrogen partitioning in Lindera umbellata leaves grown in high or low irradiance.
Seasonal changes in photosynthesis, nitrogen content and nitrogen partitioning in Lindera umbellata leaves grown in high or low irradiance.
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DOI：
10.1093/treephys/26.10.1315
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发表时间：
2006-10
期刊：
影响因子：
4
通讯作者：
Y. Yasumura;K. Hikosaka;T. Hirose
中科院分区：
文献类型：
--
作者：
Y. Yasumura;K. Hikosaka;T. Hirose
研究了落叶灌木乌药（Lindera umbellata var.）在强光和弱光照射下，从叶片成熟前（春季）到叶片死亡（秋季）光合能力、叶片氮含量和氮分配的季节变化。膜壳菌（Maxim.）Momiyama生长在日本东北部的天然森林中。在春季，光饱和光合速率（Pmax）低，尽管叶片N和Rubisco含量高，表明光合机构尚未功能发达。Rubisco似乎只有部分活性。在夏秋两季，单位叶氮的Pmax增加，Pmax的变化与叶氮和两个光合组分Rubisco和叶绿素的变化相关。这些组分的变化与叶片氮素的变化一致。在叶片衰老过程中，约70%的叶片氮被再吸收。代谢蛋白，占大多数的叶片氮在夏季是高度可降解的，足以解释高N-再吸收效率。结构蛋白只占叶片氮的一小部分，相对耐降解，因此对氮的再吸收贡献不大。叶氮分配之间的代谢和结构蛋白决定的再转运N的量，但没有严格确定的N含量的死叶或N-再吸收效率。
Seasonal changes in photosynthetic capacity, leaf nitrogen (N) content and N partitioning were studied from before leaf maturation (spring) until death (autumn) in high- and low-light-exposed leaves of a deciduous shrub, Lindera umbellata var. membranacea (Maxim.) Momiyama growing in a natural forest in northeast Japan. In spring, light-saturated photosynthetic rate (Pmax) was low despite high leaf N and Rubisco contents, indicating that the photosynthetic apparatus was not yet functionally developed. Rubisco seemed to be only partially active. In summer and autumn, Pmax per unit leaf N increased and changes in Pmax were correlated with changes in leaf N and two photosynthetic components, Rubisco and chlorophyll. Changes in these components paralleled the changes in leaf N. During leaf senescence, about 70% of leaf N was resorbed. Metabolic proteins that accounted for the majority of leaf N in summer were highly degradable and more than sufficient to explain the high N-resorption efficiency. Structural proteins represented only a small part of leaf N and were relatively resistant to degradation and thus contributed little to N resorption. Leaf N partitioning between metabolic and structural proteins determined the amount of retranslocatable N, but did not strictly determine the N content of a dead leaf or N-resorption efficiency.