植物生态学报

• •    

极端干旱对草甸草原优势植物非结构性碳水化合物的影响

宋琳1,雒文涛1,马望1,何鹏2,梁潇洒1,王正文1   

  1. 1. 中国科学院沈阳应用生态研究所
    2. 天津师范大学生命科学学院
  • 收稿日期:2019-11-30 修回日期:2020-03-23 发布日期:2020-03-26
  • 通讯作者: 雒文涛
  • 基金资助:
    国家自然科学基金;国家自然科学基金;美丽中国生态文明建设科技工程专项

Extreme drought effects on nonstructural carbohydrates of dominant plant species in a meadow grassland

lin song1, 2,wang ma1,peng he3,xiao saliang1,Zhengwen Wang1   

  1. 1. Institute of Applied Ecology, Chinese Academy of Sciences
    2.
    3. College of Life Sciences, Tianjin Normal University
  • Received:2019-11-30 Revised:2020-03-23 Published:2020-03-26

摘要: 植物光合作用产生的非结构性碳水化合物(NSCs)水平可以反映植物和生态系统对环境变化的响应程度。近年来,草原极端干旱事件的发生频率和持续时间增加趋势明显,对生态系统结构和功能产生深远影响。本研究以内蒙古呼伦贝尔草甸草原为研究对象,通过连续4年减少66%生长季降水量的控制实验来模拟极端干旱事件,分析草原6种优势物种和植物功能群NSCs各组分对极端干旱的响应规律与机制。结果显示,由于植物生物学、光合特性以及生理生态等特性的差异,不同物种对干旱胁迫的响应具有明显差异。这表明草地植物NSCs组分及其利用策略对干旱胁迫的响应具有物种特异性,从而导致其生物量的不同响应。将6种植物分为禾草和非禾草两类,进一步分析发现干旱显著增加了禾草的淀粉含量,但对其可溶性糖含量无显著影响;相反,干旱显著增加了非禾草功能群的可溶性糖含量,对其淀粉含量无显著影响,表明不同功能群采取了不一致的干旱应对策略。禾草选择将光合作用固定的能量进行储存以应对干旱胁迫,其生物量对干旱响应不敏感;而非禾草选择将能量以可溶性糖的形式直接供植物生长利用以及抵御干旱胁迫,其生物量对干旱响应较为敏感。这一发现可为预测在全球气候变化背景下草甸草原生态系统结构与功能对极端干旱的响应提供科学参考。

关键词: 关键词 极端干旱, 非结构性碳水化合物, 草原植物, 功能群, 生物量, 响应比

Abstract:
Aims Plant nonstructural carbohydrates (NSCs) produced by photosynthesis can reflect the responses of plant and/or ecosystem to environmental changes. Recently, climate change was predicted to increase the frequency and duration of extreme drought events in grasslands, exerting a profound impact on ecosystem structure and functions. Methods To explore the effects of extreme drought on the NSCs of dominant species and different functional groups in grasslands, we experimentally reduced precipitation amounts by 66% during four consecutive growing seasons in a meadow steppe in Hulunbier of China. Important findings Our results showed that different species responded differently to drought, due to their differences in plant biological characteristics, photosynthetic characteristics and physiological ecology. This result implied that different species used different NSC-use strategies to cope with drought stress, resulting in different responses of their biomass to extreme drought. The six plants are divided into two functional groups (i.e., grasses and non-grasses). For grasses, extreme drought significantly increased the starch concentrations, and had non-significant effect on the soluble sugar concentrations. For non-grasses, however, extreme drought significantly increased the soluble sugar concentrations, and had non-significant effects on the starch concentrations. The grasses preferred to store photosynthate to cope with drought stress, thus the biomass of this functional group was less sensitive, while the non-grasses preferred to directly use soluble sugar for plant growth, defense and reproduction, so the biomass of this functional group was more sensitive. This study could provide scientific data for predicting future ecosystem responses to extreme drought in the context of global climate change.

Key words: Key words extreme drought, nonstructural carbohydrates, grassland plants, functional groups, biomass, response ratio