Is salinity the main ecological factor that influences foliar nutrient resorption of desert plants in a hyper-arid envir
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RESEARCH ARTICLE
Open Access
Is salinity the main ecological factor that influences foliar nutrient resorption of desert plants in a hyper-arid environment? Lilong Wang1,2, Xinfang Zhang1 and Shijian Xu1*
Abstract Background: Soil salinity is a major abiotic constraint to plant growth and development in the arid and semi-arid regions of the world. However, the influence of soil salinity on the process of nutrient resorption is not well known. We measured the pools of both mature and senesced leaf nitrogen (N), phosphorus (P), potassium (K), and sodium (Na) of desert plants from two types of habitats with contrasting degrees of soil salinity in a hyper-arid environment of northwest China. Results: N, P, K revealed strict resorption, whereas Na accumulated in senesced leaves. The resorption efficiencies of N, P, and K were positively correlated with each other but not with Na accumulation. The degree of leaf succulence drives both intra-and interspecific variation in leaf Na concentration rather than soil salinity. Both community- and species-level leaf nutrient resorption efficiencies (N, P, K) did not differ between the different habitats, suggesting that soil salinity played a weak role in influencing foliar nutrients resorption. Conclusions: Our results suggest that plants in hyper-arid saline environments exhibit strict salt ion regulation strategies to cope with drought and ion toxicity and meanwhile ensure the process of nutrient resorption is not affected by salinity. Keywords: Nutrient retranslocation, Temperate desert, Leaf traits, Nutrient cycling, Sodium tress
Background Soils in desert environments are resource impoverished because the low and pulsed precipitation reduces soil nutrient availability by limiting the weathering of parent material and organic matter production and mineralization [1]. However, desert plants have adapted to these nutrientpoor habitats by employing a suite of leaf-level traits to conserve nutrients, including long tissue life span and tight nutrient recycling [2–4]. Nutrient resorption from senescing leaves is an important mechanism for plants to re-use mineral nutrition and makes them less dependent on * Correspondence: [email protected] 1 MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, No. 222, Southern Tianshui Road, Lanzhou 730000, China Full list of author information is available at the end of the article
external nutrient supply [5]. It has been estimated that, worldwide, on average, 60% of foliar nitrogen (N) and phosphorus (P) would be withdrawn into living tissues before leaf abscission [6]. Speculation about the importance of nutrient conservation has suggested that desert plants may rely more heavily on resorption than non-desert plants. However, there are controversial results regarding this hypothesis, with comparing data from seven desert shrubs to average values for non-desert shrubs, N and P resorption efficiency was higher in desert species (Killingbeck 1993), in contrast, six shrubs in Chihuah
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