Measurements of ¹⁸O‐P_i uptake indicate fast metabolism of phosphate in tree roots

Abstract

Keywords 18 O-phosphate uptake; 33 P-phosphate uptake; excised non-mycorrhizal roots; Fagus sylvatica; field study; Michaelis-Menten kinetics; Populus x canescens.ABSTRACT Phosphorus (P) nutrition of beech ecosystems depends on soil processes, plant internal P cycling and P acquisition. P uptake of trees in the field is currently not validated due to the lack of an experimental approach applicable in natural forests. Application of radiolabelled tracers such as 33 P and 32 P is limited to special research sites and not allowed in natural environments. Moreover, only one stable isotope of P, namely 31 P, exists. One alternative tool to measure P acquisition in the field could be the use of 18 O-labelled 31 P-phosphate ( 31 P 18 O 4 3À ). Phosphate (P i ) uptake rates calculated from the 18 O enrichment of dried root material after application of 31 P i 18 Plant Biology 21 (2019) 565-570

Impacts of Fertilization on Biologically Cycled P in Xylem Sap of Fagus sylvatica L. Revealed by Means of the Oxygen Isotope Ratio in Phosphate

“…Phosphorus (P) is an essential agent in a variety of vital processes like the build-up of DNA, RNA, and cell membranes, energy transfer via free nucleotides and carbon metabolism. Therefore, P is of paramount importance for plant growth and ecosystem performance (Marschner, 2002;Scheerer et al, 2018). Based on the decrease of foliar P concentrations during the last decades, P is suspected to limit the growth of trees (Fagus sylvatica L.; Pinus sylvestris L.) in forests and thus, forest productivity (Prietzel and Stetter, 2010;Jonard et al, 2015).…”

The Genetic Basis of Phosphorus Utilization Efficiency in Plants Provide New Insight into Woody Perennial Plants Improvement

“…An alternatively novel approach, 18 O-labelled 31 P-phosphate ( 31 P 18 O 4 3− ), could be used to measure P acquisition in the field. Measurements of 18 O-P i absorption show the rapid metabolism of Pi in the roots of trees [137].…”

“…In a word, carbohydrate depletion in roots deters P nutrition in young forest trees [136]. It has been found that P acquisition, plant internal P cycling and soil processes collectively affect P nutrition in beech ecosystems [137]. Due to the lack of an experimental method suitable for natural forests, P absorption of trees in the field is difficult to be verified.…”

A dual isotopic (32P and 18O) incubation study to disentangle mechanisms controlling phosphorus cycling in soils from a climatic gradient (Kohala, Hawaii)

“…These results were subsequently confirmed by Saaby Johansen et al (1991) and Melby et al (2013a) who showed that the loss of 18 O from 18 O labelled phosphate added to soils was related to biological activity. Scheerer et al (2019) supplied beech roots with 18 O labelled phosphate and with 33 P labelled phosphate via addition to the nutrient solution. They could not observe a correlation between root phosphate uptake determined by incorporation of 33 P and by incorporation of 18 O.…”