MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, No. 222, Southern Tianshui Road, Lanzhou, 730000, China.
Naiman Desertification Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China.
BMC Plant Biol. 2020 Oct 7;20(1):461. doi: 10.1186/s12870-020-02680-1.
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.
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.
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.
土壤盐度是世界干旱和半干旱地区植物生长和发育的主要非生物限制因素。然而，土壤盐度对养分再吸收过程的影响尚不清楚。我们在中国西北极度干旱的环境中，测量了来自两种具有不同土壤盐度的生境的沙漠植物成熟叶和衰老叶氮（N）、磷（P）、钾（K）和钠（Na）的储量。
N、P、K 表现出严格的再吸收，而 Na 则在衰老的叶片中积累。N、P 和 K 的再吸收效率彼此呈正相关，但与 Na 积累无关。叶片多汁度既驱动了叶片内种间 Na 浓度的变化，也驱动了叶片间的变化，而不是土壤盐度。不同生境间群落和种间的叶片养分再吸收效率（N、P、K）没有差异，这表明土壤盐度在影响叶片养分再吸收方面作用较弱。
我们的结果表明，在极度干旱的盐生环境中，植物表现出严格的盐离子调节策略，以应对干旱和离子毒性，同时确保养分再吸收过程不受盐度影响。
