Leaf Anatomy, Morphology and Photosynthesis of Three Tundra Shrubs after 7-Year Experimental Warming on Changbai Mountain.

Yumei Zhou,Zhijuan Tai,Gelei Meng,Mai-He Li,Lifen Jiang,Jianqiu Han,Jifeng Deng

doi:10.3390/plants8080271

Abstract

Tundra is one of the most sensitive biomes to climate warming. Understanding plant eco-physiological responses to warming is critical because these traits can give feedback on the effects of climate-warming on tundra ecosystem. We used open-top chambers following the criteria of the International Tundra Experiment to passively warm air and soil temperatures year round in alpine tundra. Leaf size, photosynthesis and anatomy of three dominant species were investigated during the growing seasons after 7 years of continuous warming. Warming increased the maximal light-saturated photosynthetic rate (Pmax) by 43.6% for Dryas. octopetala var. asiatica and by 26.7% for Rhododendron confertissimum across the whole growing season, while warming did not significantly affect the Pmax of V. uliginosum. The leaf size of Dr. octopetala var. asiatica and Rh. confertissimum was increased by warming. No marked effects of warming on anatomical traits of Dr. octopetala var. asiatica were observed. Warming decreased the leaf thickness of Rh. confertissimum and Vaccinium uliginosum. This study highlights the species-specific responses to climate warming. Our results imply that Dr. octopetala var. asiatica could be more dominant because it, mainly in terms of leaf photosynthetic capacity and size, seems to have advantages over the other two species in a warming world.

Highlights

Global climate change causes non-uniform warming, with faster and stronger warming in high latitudes and altitudes where tundra exists [1]
To better understand and predict tundra species and ecosystem responses to future warming, we studied leaf photosynthesis, morphology and anatomy of three dominant tundra shrubs (Dryas octopetala var. asiatica, Vaccinium uliginosum and Rhododendron confertissimum) which have been artificially warmed by OTCs in situ on the Changbai Mountain tundra for 7 years
The daytime soil temperature was markedly increased by 2.9 ◦ C in 2016 and 3.3 ◦ C in 2017, but the nighttime soil temperature did not change as compared to the control (Table 1)

Summary

Introduction

Global climate change causes non-uniform warming, with faster and stronger warming in high latitudes and altitudes where tundra exists [1]. Many studies have reported phenology [5], shrub expansion [6], growth [7,8], gas exchange [9], morphological changes [10], and anatomical changes [11] in tundra plants in response to warming. Among these changes, the photosynthetic adjustment was found to be relatively rapid and sensitive to warming, while alterations in leaf morphology and anatomy showed adaptive responses to long-term warming

Methods

Results

Conclusion