Delgado Mabel, Valle Susana, Reyes-Díaz Marjorie, Barra Patricio J, Zúñiga-Feest Alejandra
Laboratorio de Biología Vegetal, Facultad de Ciencias, Instituto de Ciencias Ambientales y Evolutivas, Universidad Austral de Chile, Valdivia, Chile.
Centro de Investigación en Suelos Volcánicos, Universidad Austral de Chile, Valdivia, Chile.
Front Plant Sci. 2018 Jun 27;9:883. doi: 10.3389/fpls.2018.00883. eCollection 2018.
Plants from the Proteaceae family can thrive in old, impoverished soil with extremely low phosphorus (P) content, such as those typically found in South Western Australia (SWA) and South Africa. The South Western (SW) Australian Proteaceae species have developed strategies to deal with P scarcity, such as the high capacity to re-mobilize P from senescent to young leaves and the efficient use of P for carbon fixation. In Southern South America, six Proteaceae species grow in younger soils than those of SWA, with a wide variety of climatic and edaphic conditions. However, strategies in the nutrient use efficiency of Southern South (SS) American Proteaceae species growing in their natural ecosystems remain widely unknown. The aim of this study was to evaluate nutrient resorption efficiency and the photosynthetic nutrients use efficiency by SS American Proteaceae species, naturally growing in different sites along a very extensive latitudinal gradient. Mature and senescent leaves of the six SS American Proteaceae species (, and ), as well as, soil samples were collected in nine sites from southern Chile and were subjected to chemical analyses. Nutrient resorption (P and nitrogen) efficiency in leaves was estimated in all species inhabiting the nine sites evaluated, whereas, the photosynthetic P use efficiency (PPUE) and photosynthetic nitrogen (N) use efficiency (PNUE) per leaf unit were determined in two sites with contrasting nutrient availability. Our study exhibit for the first time a data set related to nutrient use efficiency in the leaves of the six SS American Proteaceae, revealing that for all species and sites, P and N resorption efficiencies were on average 47.7 and 50.6%, respectively. No correlation was found between leaf nutrient (P and N) resorption efficiency and soil attributes. Further, different responses in PPUE and PNUE were found among species and, contrary to our expectations, a higher nutrient use efficiency in the nutrient poorest soil was not found. We conclude that SS American Proteaceae species did not show a general pattern in the nutrient use efficiency among them neither with others Proteaceae species reported in the literature.
山龙眼科植物能够在古老、贫瘠且磷（P）含量极低的土壤中茁壮成长，比如在澳大利亚西南部（SWA）和南非常见的那些土壤。澳大利亚西南部（SW）的山龙眼科物种已经形成了应对磷缺乏的策略，例如从衰老叶片向幼叶重新调动磷的能力很强，以及在碳固定过程中高效利用磷。在南美洲南部，有六种山龙眼科植物生长在比澳大利亚西南部更年轻的土壤中，且气候和土壤条件多样。然而，生长在其自然生态系统中的南美洲南部（SS）山龙眼科物种在养分利用效率方面的策略仍鲜为人知。本研究的目的是评估生长在沿非常广泛的纬度梯度分布的不同地点的南美洲南部山龙眼科物种的养分再吸收效率和光合养分利用效率。采集了六种南美洲南部山龙眼科物种（、和）的成熟叶和衰老叶，以及来自智利南部九个地点的土壤样本，并进行了化学分析。对居住在评估的九个地点的所有物种的叶片养分（磷和氮）再吸收效率进行了估算，而在两个养分有效性不同的地点测定了每叶单位的光合磷利用效率（PPUE）和光合氮（N）利用效率（PNUE）。我们的研究首次展示了与六种南美洲南部山龙眼科植物叶片养分利用效率相关的数据集，表明对于所有物种和地点，磷和氮的再吸收效率平均分别为47.7%和50.6%。未发现叶片养分（磷和氮）再吸收效率与土壤属性之间存在相关性。此外，在物种之间发现了PPUE和PNUE的不同响应，并且与我们的预期相反，在养分最贫瘠的土壤中未发现更高的养分利用效率。我们得出结论，南美洲南部山龙眼科物种在它们之间以及与文献中报道的其他山龙眼科物种相比，在养分利用效率方面没有呈现出一般模式。
