TY - JOUR

T1 - Phenotypic Plasticity Explains Response Patterns of European Beech (Fagus sylvatica L.) Saplings to Nitrogen Fertilization and Drought Events

AU - Dziedek, Christoph

AU - Fichtner, Andreas

AU - Calvo, Leonor

AU - Marcos, Elena

AU - Jansen, Kirstin

AU - Kunz, Matthias

AU - Walmsley, David

AU - Von Oheimb, Goddert

AU - Härdtle, Werner

PY - 2017/3/20

Y1 - 2017/3/20

N2 - Climate and atmospheric changes affect forest ecosystems worldwide, but little is known about the interactive effects of global change drivers on tree growth. In the present study, we analyzed single and combined effects of nitrogen (N) fertilization and drought events (D) on the growth of European beech (Fagus sylvatica L.) saplings in a greenhouse experiment. We quantified morphological and physiological responses to treatments for one- and two-year-old plants. N fertilization increased the saplings' aboveground biomass investments, making them more susceptible to D treatments. This was reflected by the highest tissue dieback in combined N and D treatments and a significant N × D interaction for leaf δ 13C signatures. Thus, atmospheric N deposition can strengthen the drought sensitivity of beech saplings. One-year-old plants reacted more sensitively to D treatments than two-year-old plants (indicated by D-induced shifts in leaf δ 13C signatures of one-year-old and two-year-old plants by +0.5% and -0.2%, respectively), attributable to their higher shoot:root-ratios (1.8 and 1.2, respectively). In summary, the saplings' treatment responses were determined by their phenotypic plasticity (shifts in shoot:root-ratios), which in turn was a function of both the saplings' age (effects of allometric growth trajectories = apparent plasticity) and environmental impacts (effects of N fertilization = plastic allometry).

AB - Climate and atmospheric changes affect forest ecosystems worldwide, but little is known about the interactive effects of global change drivers on tree growth. In the present study, we analyzed single and combined effects of nitrogen (N) fertilization and drought events (D) on the growth of European beech (Fagus sylvatica L.) saplings in a greenhouse experiment. We quantified morphological and physiological responses to treatments for one- and two-year-old plants. N fertilization increased the saplings' aboveground biomass investments, making them more susceptible to D treatments. This was reflected by the highest tissue dieback in combined N and D treatments and a significant N × D interaction for leaf δ 13C signatures. Thus, atmospheric N deposition can strengthen the drought sensitivity of beech saplings. One-year-old plants reacted more sensitively to D treatments than two-year-old plants (indicated by D-induced shifts in leaf δ 13C signatures of one-year-old and two-year-old plants by +0.5% and -0.2%, respectively), attributable to their higher shoot:root-ratios (1.8 and 1.2, respectively). In summary, the saplings' treatment responses were determined by their phenotypic plasticity (shifts in shoot:root-ratios), which in turn was a function of both the saplings' age (effects of allometric growth trajectories = apparent plasticity) and environmental impacts (effects of N fertilization = plastic allometry).

KW - Sustainability Science

KW - Allometric growth

KW - Apparent plasticity

KW - Global change

KW - Plastic allometry

KW - Shoot:root ratio

KW - δ13C

KW - Ecosystems Research

KW - allometric growth

KW - apparent plasticity

KW - δ13C

KW - global change

KW - plastic allometry

KW - shoot:root ratio

UR - http://www.scopus.com/inward/record.url?scp=85016134728&partnerID=8YFLogxK

U2 - 10.3390/f8030091

DO - 10.3390/f8030091

M3 - Journal articles

VL - 8

SP - 1

EP - 11

JO - Forests

JF - Forests

SN - 1999-4907

IS - 3

M1 - 91

ER -