Nutrient remobilization in tree foliage as affected by soil nutrients and leaf life span

Abstract

Nutrient remobilization is a key process in nutrient conservation in plants and in nutrient cycling in ecosystems. To predict the productivity of terrestrial ecosystems, we thus need to improve our understanding of the factors that control remobilization. We studied the remobilization rates of several major nutrients (N, P, S, K, Ca, and Mg) in 102 forest ecosystems representing large environmental gradients at the country scale (France). Total amounts or availability of nutrients in soils were correlated with nutrient remobilization: the larger the soil nutrient pool, the lower the remobilization rate (e.g., P remobilization decreased with increasing total or extractable inorganic P in soils). Soil type and soil parent material influenced nutrient remobilization indirectly through their effect on soil nutrients. Nutrient remobilization was also affected by the quality of soil organic matter (C:N and C:P ratios) and K‐Ca‐Mg antagonisms. In addition to soil properties, plant‐related parameters (nutrient concentrations in foliage and leaf life span) and climate variables (e.g., precipitation and actual evapotranspiration) were also correlated with nutrient remobilization. Using multivariate analysis, we found that soil nutrient richness and the life span of the leaf were generally the two most important factors controlling nutrient remobilization. As a whole, the nutrient remobilization rate is regulated by soil nutrients through negative feedback. This general ecological pattern is modulated by ecophysiological constraints of plants, mainly leaf life span or the capability of plants to move Ca through the phloem sap.

Differential effects of soil chemistry on the foliar resorption of nitrogen and phosphorus across altitudinal gradients

“…Hence, total soil P content need not represent an index of P availability for plants at the local scale, in contrast with previous studies reporting negative correlations between PRE and P total at the regional scale (Achat et al, 2018;Augusto et al, 2017). Inorganic phosphate represents the most biologically available form of soil P (Turner, 2008) while most of P total consists of stable organic or inorganic forms, for example sorbed to the surface of Al and Fe oxides or occluded in mineral compounds (Turner, 2008).…”

“…The strong negative correlations between nutrient resorption efficiencies (NRE and PRE) and nutrient concentrations in senescing leaves (N litter and P litter , respectively) mean that nutrient resorption efficiency mirrored nutrient resorption proficiency, that is the concentrations of nutrients in litterfall (Killingbeck, ). The poor correlations between nutrient resorption efficiency and nutrient concentration in green leaves suggest that foliar N or P concentrations are primarily determined by species‐specific features so that they cannot always be used as an indicator of nutrient status (Achat et al, ). Increasing δ 15 N (leaf‐soil) values across altitudinal gradients demonstrate that the plants utilized increasing fractions of organic N at higher altitudes especially through associated mycorrhizal partners (Amundson et al, ).…”

“…At the regional scale, Hayes, Turner, Lambers, and Laliberté () observed negative correlations between total soil N and P concentrations and NRE and PRE across a dune chronosequence in south‐western Australia. Similarly, Achat, Pousse, Nicolas, and Augusto () found the remobilization rates of N, P and other major elements to be regulated by soil nutrient status through negative feedback in 10 tree species at forest sites in France. Conversely, no significant correlations were found between both NRE and PRE and soil nutrient concentrations in gallery forests in the Central Black Sea Region (Özbucak et al, ).…”

“…If so, the negative feedback of soil fertility towards nutrient resorption efficiency should be mirrored by negative correlations between foliar nutrient concentrations and nutrient resorption efficiency (Liu, Liu, Guo, Wang, & Yang, 2014;Vergutz et al, 2012). However, most studies failed in supporting this hypothesis as nutrient resorption efficiency generally is unrelated to foliar nutrient concentrations (Achat et al, 2018;Aerts, 1996;Norby, Long, Hartz-Rubin, & O'Neill, 2000;Özbucak et al, 2008).…”

Magnesium accumulation, partitioning and remobilization in spring maize (Zea mays L.) under magnesium supply with straw return in northeast China

“…showed that organic matter could be used to increase maize growth and Zn accumulations in the grain in a continuous manner. Achat et al . demonstrated that organic matter, specifically carbon, as well as the N ratio in regard to carbon and the P ratio in regard to K–Ca–Mg, is one of the factors influencing remobilization in plants.…”