Abstract

Sexual dimorphism occurs regarding carbon and nitrogen metabolic processes in response to nitrogen supply. Differences in fixation and remobilization of carbon and allocation and assimilation of nitrogen between sexes may differ under severe defoliation. The dioecious species Populus cathayana was studied after two defoliation treatments with two N levels. Males had a higher capacity of carbon fixation because of higher gas exchange and fluorescence traits of leaves after severe long-term defoliation under deficient N. Males had higher leaf abscisic acid, stomatal conductance and leaf sucrose phosphate synthase activity increasing transport of sucrose to sinks. Males had a higher carbon sink than females, because under N-deficient conditions, males accumulated >131.10% and 90.65% root starch than males in the control, whereas females accumulated >40.55% and 52.81%, respectively, than females in the control group. Males allocated less non-protein N (N_Non-p) to leaves, having higher nitrogen use efficiency (photosynthetic nitrogen use efficiency), higher glutamate dehydrogenase (GDH) and higher leaf GDH expression, even after long-term severe defoliation under deficient N. Females had higher leaf jasmonic acid concentration and N_Non-p. The present study suggested that females allocated more carbon and nitrogen to defense chemicals than males after long-term severe defoliation under deficient N.

中文翻译：

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雄性和雌性青杨对氮缺乏的碳氮代谢差异。

 抽象的

响应氮供应的碳和氮代谢过程发生性别二态性。在严重落叶的情况下，两性之间碳的固定和再利用以及氮的分配和同化方面的差异可能有所不同。经过两次氮水平的落叶处理后，对雌雄异株的青杨进行了研究。雄性在缺氮条件下长期严重落叶后，由于较高的气体交换和荧光特性，具有较高的固碳能力。雄性具有较高的叶片脱落酸、气孔导度和叶片蔗糖磷酸合酶活性，增加了蔗糖向库的运输。雄性比雌性具有更高的碳汇，因为在缺氮条件下，雄性比对照雄性积累了％3E131.10％和90.65％的根淀粉，而雌性则分别比雌性积累了％3E40.55％和52.81％在对照组中。雄性分配给叶片的非蛋白氮（N _Non-p ）较少，具有较高的氮利用效率（光合氮利用效率）、较高的谷氨酸脱氢酶（GDH）和较高的叶片GDH表达，即使在缺氮条件下长期严重落叶后也是如此。雌性具有较高的叶片茉莉酸浓度和N _Non-p 。本研究表明，在氮缺乏的情况下，长期严重落叶后，雌性比雄性分配更多的碳和氮用于防御化学物质。