植物生态学报 ›› 2015, Vol. 39 ›› Issue (1): 32-42.DOI: 10.17521/cjpe.2015.0004

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糙隐子草功能性状对氮添加和干旱的响应

杨浩1,*(), 罗亚晨1,2   

  1. 1中国科学院地理科学与资源研究所, 生态系统观测与模拟重点实验室, 北京 100101
    2西南大学地理科学学院, 重庆 400715
  • 收稿日期:2014-08-04 接受日期:2014-12-09 出版日期:2015-01-10 发布日期:2015-01-22
  • 通讯作者: 杨浩
  • 作者简介:

    # 共同第一作者

  • 基金资助:
    基金项目 国家自然科学基金(31100336和31290221)

Responses of the functional traits in Cleistogenes squarrosa to nitrogen addition and drought

YANG Hao1,*(), LUO Ya-Chen1,2   

  1. 1Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
    and 2School of Geographical Sciences, Southwest University, Chongqing 400715, China
  • Received:2014-08-04 Accepted:2014-12-09 Online:2015-01-10 Published:2015-01-22
  • Contact: Hao YANG
  • About author:

    # Co-first authors

摘要:

植物功能性状被广泛地用于研究植物对环境变化的响应。糙隐子草(Cleistogenes squarrosa)是内蒙古草原重要的C4物种, 其功能性状是如何对水氮环境的变化做出响应的, 还不十分清楚。该文采用盆栽实验的方法, 进行氮添加(0, 10.5, 35.0和56.0 g·m-2·a-1)和降水(自然降水和70%平均月降水量)处理, 研究糙隐子草整株性状、叶形态性状和叶生理性状对氮添加和干旱的响应。结果表明, 氮添加显著影响了糙隐子草的整株性状, 氮、水处理及它们的交互作用显著影响了糙隐子草的叶形态性状和叶生理性状。各功能性状对氮添加的响应格局在自然降水和干旱处理下是不同的。根深、茎生物量和茎叶比在干旱条件下低和中氮添加处理中较高, 而在自然降水下无明显变化; 比叶面积在干旱条件下随氮添加量的增加而增加, 而在自然降水下无增加趋势; 自然降水下, 高氮添加显著刺激了光合速率和蒸腾速率, 增加了水分利用效率, 而在干旱条件下氮添加对它们没有显著影响; 叶片单位面积的氮含量在自然降水下随氮添加量的增加有增加趋势, 而在干旱条件下显著降低。在自然降水下, 氮添加主要影响糙隐子草的叶形态和生理性状, 而在干旱条件下, 氮添加主要影响糙隐子草的整株性状和形态性状。总之, 糙隐子草的功能性状对氮添加表现出明显的响应, 响应格局在不同的水分条件下不同, 反映了其对氮水环境变化的弹性适应。

关键词: C4植物, 叶氮含量, 形态性状, 内蒙古草原, 光合速率, 生理性状

Abstract: Aims

Plant functional traits have been widely used to study the responses of plant to environmental change. Cleistogenes squarrosa is an important C4 species in Nei Mongol grassland. How its functional traits would respond to varied nitrogen and water conditions have rarely been studied. Our subject was to examine the responses of the whole-plant traits and leaf morphological and physiological traits to nitrogen addition and drought in this species.

Methods

We conducted a pot experiment with a gradient of N addition (0, 10.5, 35.0, and 56.0 g·m-2·a-1) and water treatments (natural precipitation vs. 70% of mean monthly precipitation) in 2013. The whole-plant traits (e.g., root depth and stem-leaf biomass ratio), leaf morphological (e.g., leaf area and specific leaf area) and physiological traits (e.g., photosynthetic rate, water use efficiency, and leaf N content) were investigated.

<i>Important findings </i>

N addition had a significant effect on the whole-plant traits in C. squarrosa. The effects of N addition, water treatments, and an interaction between N addition and water treatments on leaf morphological and physiological traits were highly significant in most cases. The patterns of functional traits in response to N addition differed between plants under natural precipitation and with reduced mean monthly precipitation. Root depth, stem biomass, and stem-leaf biomass ratio were increased in treatments with low and intermediate N additions under reduced precipitation, but not changed under natural precipitation. Specific leaf area increased along the N addition gradient under drought, but did not change under natural precipitation. High N addition stimulated photosynthetic rate and transpiration rate and increased water use efficiency under natural precipitation, but had no effect on under reduced precipitation. Leaf N content on area basis increased slightly with the increases in N addition under natural precipitation, but decreased significantly under reduced precipitation. N addition influenced mainly the leaf morphological and physiological traits under natural precipitation and the whole-plant traits and leaf morphological traits under reduced precipitation. In conclusion, our results indicate that the functional traits in C. squarrosa respond to N addition and the patterns of responses differ under different water conditions, reflecting the adaptation to changes in N and water availability.

Key words: C4 plant, leaf nitrogen content, morphological traits, Nei Mongol grassland, photosynthetic rate, physiological traits