Trolox-equivalent antioxidant capacity and composition of five alpine plant species growing at different elevations on the Qinghai–Tibetan Plateau

Abstract

Background: Alpine plants on the Qinghai–Tibetan Plateau are exposed to an extremely harsh environment, namely severe cold, strong ultraviolet radiation, hypoxia and low CO₂ partial pressure. These conditions are sources of oxidative stress, which increase in severity with increasing elevation.

Aims: To examine whether antioxidant capacity and chemical composition of alpine plants change with increasing elevation.

Methods: We measured the Trolox-equivalent antioxidant capacity (TEAC) and chemical composition of five alpine plant species at 3016, 3814 and 4621 m a.s.l.

Results: With increasing elevation: (1) the TEAC increased and total phenols and tannins tended to increase in two forb and two shrub species but not in a sedge species; (2) concentrations of protein and fat increased in all five plant species; (3) polyunsaturated fatty acids (PUFA) increased and (4) mineral concentrations tended to decrease, but trends were inconsistent.

Conclusions: We conclude that with increasing elevation, TEAC and total phenols and tannins increased which we interpreted as an adaptation to higher oxidative stress; and protein and fat contents increased to support high metabolic activity. The increase in PUFA and the trend for minerals to decrease with increasing elevation require further investigation.

Keywords:

• antioxidant capacity
• elevation
• environmental stress
• oxidative stress
• plant adaptation
• polyunsaturated fatty acids
• Qinghai–Tibetan Plateau
• tannins

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Corrigendum

Acknowledgements

We thank two anonymous reviewers and Laslo Nagy for their helpful suggestions on earlier drafts of this manuscript.

Disclosure statement

The authors declare that they have no conflict of interest.

Additional information

Funding

The study was supported financially by the Chinese National Natural Science Foundation project (31560663), “Studies on signal transduction mechanism of regulating dry resistance of Medicago sativa”, and the project (31372368) “research on inter-annual dynamic variation of carbon storage and sequestrating mechanism of alfalfa in the Loess Plateau”.

Notes on contributors

Guangxin Cui

Guangxin Cui is a researcher who studies alpine plants and their effect on milk composition.

Xiaohong Wei

Xiaohong Wei is a researcher specialising in plant biology.

A. Allan Degen

A. Allan Degen is a professor of environmental physiology and does research on plant–animal relations.

Xiaoxing Wei

Xiaohong Wei is a researcher specialising in plant biology.

Jianwei Zhou

Jianwei Zhou is a researcher who studies forages, in particular alpine forages, for livestock use.

Luming Ding

Luming Ding is a researcher who studies forages for livestock, in particular, yaks and sheep.

Zhanhuan Shang

Zhanhuan Shang is a professor who does research on landscape ecology, in particular, the Qinghai–Tibetan Plateau.

Shimin Liu

Shimin Liu does research on the nutrition of forages for livestock.

Ruijun Long

Ruijun Long is a professor who does research on high altitude plants and animals.