Contrasting Leaf Trait Responses of Conifer and Broadleaved Seedlings to Altered Resource Availability Are Linked to Resource Strategies.

Yan-Li Zhang,Barbara Moser,Mai-He Li,Christoph Bachofen,Jing-Pin Lei,Thomas Wohlgemuth

doi:10.3390/plants9050621

Abstract

(1) Understanding tree seedling responses to water, nutrient, and light availability is crucial to precisely predict potential shifts in composition and structure of forest communities under future climatic conditions. (2) We exposed seedlings of widespread Central European tree species with contrasting leaf habit, deciduous broadleaves (DB) and evergreen conifers (EC), to factorial combinations of manipulated precipitation (100% and 50% of ambient), shade (40% and 60% of full sunlight), and nutrient availability (low and high NPK), and measured specific leaf area, C/N ratio, soluble sugars, starch and non-structural carbohydrate concentration, and δ13C of the leaves. (3) We found contrasting effects of water and nutrient availability on foliar traits of the two species groups: EC exhibited higher tolerance to low resource availability but also less plasticity in foliar traits, which is congruent with a “slow” resource strategy. In contrast, foliage of DB reacted particularly to altered nutrient availability, corresponding to a “fast” resource strategy with high foliar plasticity and rapid adjustments to resource fluctuations, commonly adopted by species with high growth rates. (4) We conclude that DB will respond to environmental change with foliar acclimation, while EC will either tolerate, to some extent, or shift their distribution range in response to environmental change.

Highlights

Changes in water availability are expected to shape the future distribution of tree species in Europe [1,2,3]
The specific leaf area (SLA) of evergreen conifers (EC) was affected by both precipitation nutrients, but the seedlings responses depended on light availability (Table 1)
Photosynthetically active radiation (PAR), seedlings grown at reduced precipitation (L60 × P50 ) showed showed higher SLA compared to seedlings grown at ambient precipitation (L60 × P100), while seedlings higher SLA compared to seedlings grown at ambient precipitation (L60 × P100 ), while seedlings in in mesocosms with reduced nutrient availability (L60 × N) formed needles with lower SLA than those mesocosms with reduced nutrient availability (L60 × N) formed needles with lower SLA than those in high nutrient ones (L60 × Nhi, Figure 1)

Summary

Introduction

Changes in water availability are expected to shape the future distribution of tree species in Europe [1,2,3]. Since soil nutrient availability affects plant growth and biomass allocation, it is likely to influence plant performance under drought [11]. Vice-versa, water availability alters soil nutrient status by changing ion mobility and microbial activity [12]. It is, still unclear whether high levels of soil nutrients aggravate or mitigate drought stress for trees [11,13]. Still unclear whether high levels of soil nutrients aggravate or mitigate drought stress for trees [11,13]

Methods

Results

Discussion

Conclusion