Foliar P nutrition of European beech (Fagus sylvatica L.) depends on the season but remains unaffected by co-cultivation with silver fir (Abies alba Mill.)

Abstract

Beech (Fagus sylvatica) and silver fir (Abies alba) are often cultivated in mixed stands and, hence, compete for water and nutrients. Besides nitrogen (N), also phosphorus (P) is an important nutrient for growth and development. Beech trees in Central Europe grow on both P-poor and P-rich soils, thereby showing similar growth and low variation in foliar P. The central aim of the present study was to test the hypothesis that variations in foliar P contents of beech are driven by seasonal changes rather than by the competition with silver fir. It was further hypothesized that P contents in silver fir needles depend on needle age and forest site. To test these hypotheses, P contents and P fractions, i.e. organic-bound P (Porg) and inorganic phosphate P (Pi), were measured in the foliage of beech trees from pure beech and mixed beech/silver fir plots as well as in needles of silver fir of the mixed plots. The forest sites investigated are located in Central Europe in the Black Forest, Germany, and in Croatia near the south-eastern distribution limit of beech and are all poor in plant-available soil P. The analyses showed that the main driver of P contents and P fractions in beech leaves at all forest sites is the season and that competition with silver fir had no effect. Hence, the present results demonstrate the high plasticity of beech trees to adapt to both poor plant-available soil P and competition with silver fir. Total P contents of silver fir needles were higher at the Croatian site compared to the Black Forest sites and originated from higher foliar Pi contents. One third of the P present in current-year needles in late summer was remobilized and exported until the needles reached the age of 1 year. The difference in P contents between current-year and 1-year-old needles can be seen as the amount of P resorbed from 1-year-old needles in summer during the generation of new needles to support the P demand of current-year needles for growth and development.

Memory Effects of Water Deprivation in European Beech (Fagus sylvatica L.) and Silver Fir (Abies alba Mill.) Seedlings Grown in Mixed Cultivation

“…The total N contents observed in this study were in the range previously found in European beech and fir [33,53,[87][88][89]. They were largely conserved in the year subsequent to water deprivation in beech, due to stable protein contents, which is the main cytoplasmic N pool in this species [18,33,88,89]. Therefore, our second hypothesis, that memory effects are established in both leaves and roots as altered C and N contents, is only supported for C, but not for N.…”

“…Compared to C dynamics, information on post-stress responses of N contents and partitioning in trees is extremely scarce, despite this knowledge being of particular importance for predicting the resilience of forests under climate change conditions [31,86]. The total N contents observed in this study were in the range previously found in European beech and fir [33,53,[87][88][89]. They were largely conserved in the year subsequent to water deprivation in beech, due to stable protein contents, which is the main cytoplasmic N pool in this species [18,33,88,89].…”

“…Enrichment analysis showed that the biosynthesis of amino acids is involved in chloroplast-related memory transcripts in rice (Oryza sativa L) [37]. Accumulation of N in the form of amino acids are frequently observed in beech seedlings [24,32,92] and in mature beech-fir mixtures [33,88,89] in response to reduced water availability, as well as in other plant species under stress [5,12,21,22,91]. In the present study, strong drought-mediated memory effects on foliar amino acid metabolism were revealed by significantly declined foliar total amino acid contents of both beech and fir seedlings, whereas no significant memory effects on amino acid contents were observed in roots (Figure 4).…”

Variation in Leaf Morphological Traits of European Beech and Norway Spruce Over Two Decades in Switzerland

“…Our temporal models for beech LMTs indicate a positive effect of foliar N concentration on DM100 and LA and a negative effect of foliar Ca and P concentrations on LA and LMA (Table 4). N is the most important and growth-limiting nutrient in beech trees in temperate forests (Yang et al, 2020), and the positive effect of foliar N concentration on DM100 and LA is in line with the knowledge that foliar N concentrations increase linearly with the photosynthetic capacity per unit leaf mass (Chapin and Eviner, 2004). The interpretation of the negative relationship of foliar Ca and P with LA and LMA is less straightforward.…”

Low phosphorus induces differential metabolic responses in eucalyptus species improving nutrient use efficiency

“…Plant P status has multiple effects in almost all aspects of plant metabolism, and there is insufficient knowledge on the effects of P deficiency on metabolite levels in evergreen trees ( Warren, 2011 ; Netzer et al, 2018 ; Yang et al, 2020 ). In the present study, the hierarchical cluster analysis of primary metabolites from leaves differentiated E. acmenoides from the other species.…”