J Plant Ecol ›› 2020, Vol. 13 ›› Issue (3): 295-303.DOI: 10.1093/jpe/rtaa014

• Research Articles • Previous Articles     Next Articles

Tallow tree allocates contrasting secondary chemicals in response to varying environments along elevational gradients

Li Xiao1,2,3,†, Jialiang Zhang1,2,3,†, Wei Huang1,3, Juli Carrillo4, Evan Siemann5 and Jianqing Ding6,*   

  1. 1 CAS Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, Hubei 430074, China, 2 University of Chinese Academy of Sciences, Beijing 100049, China, 3 Core Botanical Garden, Chinese Academy of Sciences, Wuhan, Hubei 430074, China, 4 Faculty of Land and Food Systems, Centre for Sustainable Food Systems, Biodiversity Research Centre, University of British Columbia, Vancouver, BC V6T 1Z4, Canada, 5 Biosciences Department, Rice University, Houston, TX 77005, USA, 6 State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, Henan 475004, China

    *Corresponding author. E-mail: jding@henu.edu.cn
  • Received:2020-01-06 Revised:2020-03-10 Accepted:2020-04-02 Online:2020-04-03 Published:2020-06-01

Abstract:

Aims

Understanding how tree species regulate multiple types of secondary chemicals along elevational gradients is critical for elucidating the physiological and ecological strategies of plants in response to varying biotic and/or abiotic environments. This study aims to examine how Chinese tallow tree (Triadica sebifera) allocates resources to the production of different secondary chemicals in response to varying environments across elevational gradients.

Methods

We conducted field surveys of different herbivore feeding guilds and their damage rates on Chinese tallow trees along an elevational gradient in China and measured secondary chemicals (tannins and flavonoids) in damaged and undamaged leaves.

Important Findings

The odds of a leaf being damaged (chewing or scarring) decreased with elevation. Flavonoid concentrations increased with elevation in undamaged leaves but decreased with elevation in damaged leaves, with quercitrin contributing most strongly to this pattern, likely as results of plant responding to changing biotic or abiotic stresses along elevational gradients. Tannin concentrations did not vary with elevation, so undamaged leaves had relatively lower tannin to flavonoid ratios at high elevation than at low elevation. Our study reveals variation in herbivory and contrasting trends in plant secondary metabolism along an elevation gradient and highlights the importance of simultaneously considering multiple types of secondary chemicals in plant physiological and ecological strategies.

Key words: herbivory, climate, elevation, defence strategies, secondary metabolites, Chinese tallow tree

摘要:
了解树木如何沿海拔梯度调节多种类型的次生代谢产物对于阐明植物如何采用生理和生态策略来应对各种生物及非生物环境变化至关重要。本研究旨在探索乌桕如何分配不同的次生代谢产物来响应海拔梯度上的环境变化。我们在中国沿海拔梯度对乌桕不同取食类型的植食性昆虫及其对乌桕叶片的危害率进行了野外实地调查,并对健康叶片和虫害叶片中的次生代谢产物(单宁和黄酮类)进行了测定分析。研究结果表明,乌桕叶片被危害(咀嚼或潜叶式危害)的可能性随海拔的升高而减小。遭受虫害叶片和未遭受虫害的健康叶片中黄酮类化合物的浓度随海拔梯度变化呈现相反的趋势,即随着海拔的升高,健康叶片和遭受虫害叶片受不同的生物和非生物因素驱动,健康叶片中黄酮类化合物浓度增加,而遭受虫害叶片中黄酮类化合物浓度下降,其中槲皮苷对黄酮类化合物随海拔梯度变化的贡献最大。单宁浓度随海拔梯度的变化未发生显著变化,高海拔地区乌桕健康叶片中单宁与黄酮类化合物的比例与低海拔相比相对较低。我们的研究揭示了沿海拔梯度昆虫植食性以及不同植物次生代谢产物的变化趋势,并强调了在理解植物的生理和生态策略中同时考虑多种次生代谢物质的重要性。

关键词: 植食性, 气候, 海拔, 防御策略, 次生代谢产物, 乌桕