Photosynthetic nitrogen-use efficiency of species that differ inherently in specific leaf area
Photosynthetic nitrogen-use efficiency of species that differ inherently in specific leaf area
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DOI：
10.1007/s004420050560
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发表时间：
1998-08-01
期刊：
影响因子：
2.7
通讯作者：
Evans, JR
中科院分区：
文献类型：
--
作者：
Poorter, H;Evans, JR
研究了导致光合氮利用效率（PNUE，二氧化碳同化率与叶片有机氮含量之比）种间差异的因素，比较了十种在特定叶面积（SLA，叶面积：叶干质量）方面存在固有差异的双子叶植物物种。植物在受控环境柜中在两种辐照度（200 和 1000 mu mol m(-2) s(-1)）下进行水培生长。测量光合作用的二氧化碳和辐照度响应曲线，然后分析叶片的叶绿素、Rubisco、硝酸盐和总氮含量。在这两种辐照度下，不同物种的 SLA 变化幅度超过两倍。高 SLA 物种每单位叶量的原位光合作用速率较高，但面积速率相似。高 SLA 物种的每单位叶面积有机氮含量较低，因此这些植物在环境光条件下的 PNUE (PNUEamb) 较高。当在饱和辐照度 (PNUEmax) 下确定 PNUE 时，差异稍小，但仍然存在。对造成 PNUE 种间变异的各种因素的相对重要性进行了评估。对于在低辐照度下生长的植物，高 SLA 物种的 PNUEamb 较高，主要是因为其单位叶面积的氮含量较低。在这些条件下，低 SLA 物种显然对光合氮进行了过度投资。此外，高 SLA 物种将较大比例的有机氮分配给类囊体和 Rubisco，这进一步增加了 PNUEamb。在高辐照度下生长的高 SLA 物种表现出较高的 PNUEamb，这主要是由于较高的 Rubisco 比活性。其他促成因素还包括每单位叶面积的 N-org 含量较低以及电子传输和 Rubisco 中光合 N 的比例较高。对于 PNUEmax，物种之间有机叶氮含量本身的差异不再重要，高 SLA 物种较高的 PNUEmax 是由于光合化合物中氮的比例较高（对于弱光植物）和较高的 Rubisco 比活性（对于强光生长的植物）。
Factors that contribute to interspecific variation in photosynthetic nitrogen-use efficiency (PNUE, the ratio of CO2 assimilation rate to leaf organic nitrogen content) were investigated, comparing ten dicotyledonous species that differ inherently in specific leaf area (SLA, leaf area:leaf dry mass). Plants were grown hydroponically in controlled environment cabinets at two irradiances (200 and 1000 mu mol m(-2) s(-1)). CO2 and irradiance response curves of photosynthesis were measured followed by analysis of the chlorophyll, Rubisco, nitrate and total nitrogen contents of the leaves. At both irradiances, SLA ranged more than twofold across species. High-SLA species had higher in situ rates of photosynthesis per unit leaf mass, but similar rates on an area basis. The organic N content per unit leaf area was lower for the high-SLA species and consequently PNUE at ambient light conditions (PNUEamb) was higher in those plants. Differences were somewhat smaller, but still present, when PNUE was determined at saturating irradiances (PNUEmax). An assessment was made of the relative importance of the various factors that underlay interspecific variation in PNUE. For plants grown under low irradiance, PNUEamb of high-SLA species was higher primarily due to their lower N content per unit leaf area. Low-SLA species clearly had an overinvestment in photosynthetic N under these conditions. In addition, high SLA-species allocated a larger fraction of organic nitrogen to thylakoids and Rubisco, which further increased PNUEamb. High-SLA species grown under high irradiance showed higher PNUEamb mainly due to a higher Rubisco specific activity. Other factors that contributed were again their lower contents of N-org per unit leaf area and a higher fraction of photosynthetic N in electron transport and Rubisco. For PNUEmax, differences between species in organic leaf nitrogen content per se were no longer important and higher PNUEmax of the high SLA species was due to a higher fraction of N in photosynthetic compounds (for low-light plants) and a higher Rubisco specific activity (for high-light grown plants).