Dominant Species in Subtropical Forests Could Decrease Photosynthetic N Allocation to Carboxylation and Bioenergetics and Enhance Leaf Construction Costs during Forest Succession.

Yihua Xiao,Shirong Liu,Yuanwen Kuang,Fuchun Tong,Bufeng Chen

doi:10.3389/fpls.2018.00117

Abstract

It is important to understand how eco-physiological characteristics shift in forests when elucidating the mechanisms underlying species replacement and the process of succession and stabilization. In this study, the dominant species at three typical successional stages (early-, mid-, and late-succession) in the subtropical forests of China were selected. At each stage, we compared the leaf construction costs (CC), payback time (PBT), leaf area based N content (NA), maximum CO2 assimilation rate (Pmax), specific leaf area (SLA), photosynthetic nitrogen use efficiency (PNUE), and leaf N allocated to carboxylation (NC), and to bioenergetics (NB). The relationships between these leaf functional traits were also determined. The results showed that the early-succession forest is characterized with significantly lower leaf CC, PBT, NA, but higher Pmax, SLA, PNUE, NC, and NB, in relation to the late-succession forest. From the early- to the late-succession forests, the relationship between Pmax and leaf CC strengthened, whereas the relationships between NB, NC, PNUE, and leaf CC weakened. Thus, the dominant species are able to decrease the allocation of the photosynthetic N fraction to carboxylation and bioenergetics during forest succession. The shift in these leaf functional traits and their linkages might represent a fundamental physiological mechanism that occurs during forest succession and stabilization.

Highlights

Understanding plant community succession is a fundamental objective of ecology (Buma et al, 2017)
Leaf construction costs (CC) increased with the forest succession, with the highest mean being recorded for the late-succession forest (BF, Figure 1A)
Like leaf CC, leaf payback time (PBT) increased along the successional stages, from 42.76 h in the early-successional forest (PF) to 332.05 h in the late-successional forest (BF, Figure 1B)

Summary

Introduction

Understanding plant community succession is a fundamental objective of ecology (Buma et al, 2017). Many of the functional traits could, individually or in combination, indicate how plants respond to environmental change (Pratt and Mooney, 2013; Rillig et al, 2015) Examples of such traits include leaf construction costs (hereafter, leaf CC; Poorter and Evans, 1998; Pýankov et al, 2011; Falcão et al, 2015, 2017; Kunstler et al, 2016), leaf morphology, stoichiometry, and physiology (Raevel et al, 2012; Böhnke et al, 2014; Chai et al, 2016), and leaf photosynthetic characteristics (Feng et al, 2007; Hikosaka, 2014). These traits could be used to explore the dynamics of plant communities and the processes of forest ecosystems (Picotte et al, 2009; Navas et al, 2010; Pýankov et al, 2011; Raevel et al, 2012; Boukili and Chazdon, 2017)

Methods

Results

Discussion

Conclusion