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CAS Workshop on Ecosystem Succession Theory and Practice of Ecological Restoration

植物光合作用对空气NH₃的响应：SLA和氮分配的相对重要性

孙谷畴　赵平　曾小平　彭少麟

（中国科学院华南植物研究所，广州　510650）

摘要：研究了空气NH₃增高条件下生长在NO₃^－、NH₄^＋和NH₄NO₃的大叶相思和阴香的比叶面积（SLA）和叶蛋白氮分配的变化。在生长光强下，增高空气NH₃的植株叶片单位叶面积光合速率较空气下的平均增高17%至19.5%。生长在增高空气NH₃下的植株，其SLA与空气下生长的无显著差别(P>0.05)。无论向根供给何种氮源，生长在增高空气NH₃下的植株，其单位叶干重的氮浓度较空气下生长的高。与生长在空气下的植株相比较，生长在增高NH₃下的植株色素蛋白氮(mmol m^-2)降低；而结合光合电子传递链的氮则增高22.3%至26%。表明生长在增高空气NH₃下的植株分配较多氮至电子传递链和光合磷酸化组分。对于生长在增高空气NH₃下植株的光合碳同化，类囊体膜蛋白氮分配的变化较SLA变化为重要。

关键词：光合速率；SLA；氮分配；增高空气NH₃

Photosynthetic responses to atmospheric NH₃: the relative importance of specific leaf area and nitrogen partitioning in photosynthetic carbon gain

Sun Guchou Zhao Ping Zeng Xiaoping Peng Shaolin

(South China Institute of Botany, Academia Sinica, Guangzhou 510650, China)

Abstract: Changes in specific leaf area (SLA) and nitrogen partitioning between protein within leaves occurred in plants of Acacia auriculaeformis and Cinnamomum burmonni grown in NO₃^-,NH₄⁺or NH₄NO₃ during the exposure to elevated NH₃ in atmosphere, photosynthetic rate per unit leaf area measured under grown irradiance was, on average 17% to 19.5% higher for plants grown under elevated NH₃ than those grown under ambient condition, plant grown in elevated NH₃ had not significant change in SLA (P>0.05) as comparison with that grown in ambient. However nitrogen concentrations per unit leaf mass were higher than that of plants grown under ambient evironment regardless of what extraneous nitrogen sources supplied to roots. Pigment protein nitrogen (mmol m^-2) was decreased in plant grown in elevated NH₃ and that associated with photosynthetic electron transport chain (mmol m^-2) increased by 22.3% to 26%. Plants grown in elevated NH₃ partitioned a larger fraction of leaf nitrogen into the components of electron transport chain and photophosphorylation. Photosynthetic rate was much responsive to changes nitrogen partitioning into thylakoid protein and the changes in SLA was not much important.

Keywords: photosynthetic rate; SLA; nitrogen partitioning; elevated NH₃ in atmosphere

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