Effects of light acclimation on shoot morphology, structure, and biomass allocation of two Taxus species in southwestern China.

Wande Liu,Jianrong Su

doi:10.1038/srep35384

Wande Liu, Jianrong Su

Open Access

https://doi.org/10.1038/srep35384

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Abstract

Acclimation to changing light conditions plays a crucial role in determining the competitive capability of tree species. There is currently limited information about acclimation to natural light gradient and its effect on shoot structure and biomass in Taxus species. We examined the acclimation of the leaf and shoot axis morphology, structure and biomass allocation of Taxus yunnanensis and T. chinensis var. mairei under three different natural light environments, full daylight, 40–60% full daylight and <10% full daylight. The leaf biomass, nitrogen content per unit area, leaf carbon content per dry mass and leaf dry mass to fresh mass ratio increased with light in both species, demonstrating an enhanced investment of photosynthetic biomass and structural investment under high light. The number of leaves per unit shoot axis length and the leaf dry mass per unit shoot axis length increased with light in both species. However, the light increase did not result in the increase of the total shoot mass. T. yunnanensis produced larger leaves under low light and a higher shoot axis length per unit dry mass under high light, whereas the leaf size and biomass yield of T. chinensis var. mairei were not sensitive to light.

Highlights

Acclimation to changing light conditions typically plays a crucial role in determining the competitive capacity of forest tree species[1,2]
T. yunnanensis had a higher AL in low light and leaf dry mass per unit area (LMA) in middle and high light compared with T. chinensis var. mairei (P < 0.05)
T. yunnanensis had larger leaves under low light, greater LMA under moderate and high levels of light, higher leaf carbon content per unit dry mass under all light conditions, and lower leaf nitrogen content per unit dry mass (Nmass) under high light compared with T. chinensis var. mairei

Summary

Introduction

Acclimation to changing light conditions typically plays a crucial role in determining the competitive capacity of forest tree species[1,2]. Leaf adaptations to light include changes in leaf morphology, physiology and structure such as sun leaves. Sun leaves, which grow in exposed conditions of the canopy, are thicker, smaller or more slender and have a greater mass per area[8], a higher volume of photosynthetic machinery per unit leaf area[9] and higher growth rates[10] than shade leaves. Acclimation to changing light conditions can be achieved through adjustments in biomass allocation to various organs, such as leaves and the shoot axis[14,17]. Plants enhance the interception of light with a large leaf area per unit leaf biomass[3] and shade leaves enhance the potential relative growth rates through little physiological activity (slow respiration and light-saturated photosynthetic rates). A quantitative understanding of biomass allocation patterns is of fundamental importance to plant ecology and evolution and is useful for agricultural and forest practices and implementation[20]

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