Responses of foliar phosphorus fractions to soil age are diverse along a 2 Myr dune chronosequence

Abstract

Summary Plants respond to soil phosphorus (P) availability by adjusting leaf P among inorganic P (Pi) and organic P fractions (nucleic acids, phospholipids, small metabolites and a residual fraction). We tested whether phylogenetically divergent plants in a biodiversity hotspot similarly adjust leaf P allocation in response to P limitation by sampling along a 2 Myr chronosequence in southwestern Australia where nitrogen (N) limitation transitions to P limitation with increasing soil age. Total P and N, and P allocated to five chemical fractions were determined for photosynthetic organs from Melaleuca systena (Myrtaceae), Acacia rostellifera (Fabaceae) and Hakea prostrata (Proteaceae). Soil characteristics were also determined. Acacia rostellifera maintained phyllode total P and N concentrations at c. 0.5 and 16 mg g−1 DW, respectively, with a constant P‐allocation pattern along the chronosequence. H. prostrata leaves allocated less P to Pi, phospholipids and nucleic acids with increasing soil age, while leaf N concentration was constant. M. systena had the greatest variation in allocating leaf P, whereas leaf N concentration decreased 20% along the chronosequence. Variation in P‐allocation patterns was only partially conserved among species along the chronosequence. Such variation could have an impact on species distribution and contribute to species richness in P‐limited environments.

Elevated [CO2] concentration and nitrogen addition affects responses of foliar phosphorus fractions in invasive species to increased phosphorus supply

“…Organic P fractions were sequentially extracted (Hidaka and Kitayama, 2013) following methods of Kedrowski (1983) and Close & Beadle (2004). Foliar Pi was extracted by the acetic-acid extraction method (Yan et al, 2019), and determined using a molybdenum blue-based method (Ames, 1966). The four fractions of organic P were determined in the following steps.…”

“…Lipid P comprises phospholipids, most of which are components of the plasmalemma and organelle membranes (Veneklaas et al, 2012). Finally, the uncharacterized residual fraction may include phosphorylated proteins, some of which regulate cellular processes (Yan et al, 2019). Despite studies on allocation of leaf P fractions following N or P addition (Mo et al, 2019) and in different soil condition (e.g., soil age; Yan et al, 2019), there is little information concerning the interactive effects of elevated [CO 2 ], N addition, and low soil P availability on the allocation of P to the five foliar P fractions in invasive species (Song et al, 2009; Tissue and Lewis, 2010; Zhang et al, 2016).…”

Using activated charcoal to remove substances interfering with the colorimetric assay of inorganic phosphate in plant extracts

“…The variability of Pi concentration ([Pi]) in plant organs reflects differences in P uptake and demand which makes [Pi] a sensitive indicator of plant P status (Bollons and Barraclough 1999;Veneklaas et al 2012). For this reason, leaf [Pi] is used to understand how P availability influences species distribution and to identify strategies for P-use and -acquisition in plants (Zohlen and Tyler 2004;Yan et al 2019). Plants that evolved in severely P-impoverished landscapes are able to mobilise sorbed P in soils, then use and recycle P very efficiently in metabolism and growth (Denton et al 2007;Hayes et al 2014Hayes et al , 2021, and knowledge about their strategies and requirements can guide us toward the development of more sustainable P-efficient cropping systems (Lambers et al 2011).…”

“…Hence, the determination of leaf [Pi] in these plants requires sampling and extraction procedures that maximise precision and accuracy: an extraction protocol that causes minimal enzymemediated hydrolysis of organic P and conversion into Pi, as well as sensitive quantification methods. These requirements can be achieved by the procedures reported by Yan et al (2019) which involve immediately freezing samples in liquid nitrogen upon collection followed by storage at −80 °C until freezedrying, Pi extraction with an ice-cold 1% ( v / v ) acetic acid solution, and Pi quantification with a colorimetric assay (Ames 1966).…”

“…Here, we report an issue with the quantification of leaf Pi in samples of some native species inhabiting severely nutrient-impoverished soils of the Southwest Australian Floristic Region exhibiting low leaf [P] when following the procedures described by Yan et al (2019). The presence of organic substances of unknown nature interferes with the colour formation of the molybdate and malachite green method (Motomizu et al 1983;Figs.…”